Removes gratuitous (double)x.yF casts (#632)

* Committing clang-format changes

* Removes gratuitous (double)x.yF casts

* Committing clang-format changes

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

43 files changed, 291 insertions, 300 deletions

diff --git a/c++/test/dsets.cpp b/c++/test/dsets.cpp
index 356112e..0363bba 100644
--- a/c++/test/dsets.cpp
+++ b/c++/test/dsets.cpp
@@ -1157,7 +1157,7 @@ test_chunk_cache(const FileAccPropList &fapl)
         // Verify that chunk cache parameters are the same
         int    mdc_nelmts = 0;
         size_t nslots_1 = 0, nslots_4 = 0, nbytes_1 = 0, nbytes_4 = 0;
-        double w0_1 = 0.0F, w0_4 = 0.0F;
+        double w0_1 = 0.0, w0_4 = 0.0;
         fapl_def.getCache(mdc_nelmts, nslots_1, nbytes_1, w0_1);
         dapl.getChunkCache(nslots_4, nbytes_4, w0_4);
         verify_val(nslots_1, nslots_4, "DSetAccPropList::getChunkCache", __LINE__, __FILE__);
@@ -1175,7 +1175,7 @@ test_chunk_cache(const FileAccPropList &fapl)
         // Set new rdcc settings on fapl local
         size_t nslots_2 = nslots_1 * 2;
         size_t nbytes_2 = nbytes_1 * 2;
-        double w0_2     = w0_1 / (double)2.0F;
+        double w0_2     = w0_1 / 2.0;
         fapl_local.getCache(mdc_nelmts, nslots_2, nbytes_2, w0_2);
 
         // Create a new file using default fcpl and the passed-in fapl
diff --git a/hl/src/H5LT.c b/hl/src/H5LT.c
index fbd2be0..fb507e7 100644
--- a/hl/src/H5LT.c
+++ b/hl/src/H5LT.c
@@ -822,7 +822,7 @@ H5LTopen_file_image(void *buf_ptr, size_t buf_size, unsigned flags)
     char     file_name[64];           /* Filename buffer */
     size_t   alloc_incr;              /* Buffer allocation increment */
     size_t   min_incr  = 65536;       /* Minimum buffer increment */
-    double   buf_prcnt = 0.1f;        /* Percentage of buffer size to set
+    double   buf_prcnt = 0.1;         /* Percentage of buffer size to set
                                           as increment */
     static long                 file_name_counter;
     H5FD_file_image_callbacks_t callbacks = {&image_malloc, &image_memcpy, &image_realloc, &image_free,
diff --git a/src/H5C.c b/src/H5C.c
index 1b885e3..7853933 100644
--- a/src/H5C.c
+++ b/src/H5C.c
@@ -445,17 +445,17 @@ H5C_create(size_t max_cache_size, size_t min_clean_size, int max_type_id,
     (cache_ptr->resize_ctl).max_increment       = H5C__DEF_AR_MAX_INCREMENT;
 
     (cache_ptr->resize_ctl).flash_incr_mode = H5C_flash_incr__off;
-    (cache_ptr->resize_ctl).flash_multiple  = (double)1.0f;
-    (cache_ptr->resize_ctl).flash_threshold = (double)0.25f;
+    (cache_ptr->resize_ctl).flash_multiple  = 1.0;
+    (cache_ptr->resize_ctl).flash_threshold = 0.25;
 
     (cache_ptr->resize_ctl).decr_mode              = H5C_decr__off;
-    (cache_ptr->resize_ctl).upper_hr_threshold     = (double)H5C__DEF_AR_UPPER_THRESHHOLD;
-    (cache_ptr->resize_ctl).decrement              = (double)H5C__DEF_AR_DECREMENT;
+    (cache_ptr->resize_ctl).upper_hr_threshold     = H5C__DEF_AR_UPPER_THRESHHOLD;
+    (cache_ptr->resize_ctl).decrement              = H5C__DEF_AR_DECREMENT;
     (cache_ptr->resize_ctl).apply_max_decrement    = TRUE;
     (cache_ptr->resize_ctl).max_decrement          = H5C__DEF_AR_MAX_DECREMENT;
     (cache_ptr->resize_ctl).epochs_before_eviction = H5C__DEF_AR_EPCHS_B4_EVICT;
     (cache_ptr->resize_ctl).apply_empty_reserve    = TRUE;
-    (cache_ptr->resize_ctl).empty_reserve          = (double)H5C__DEF_AR_EMPTY_RESERVE;
+    (cache_ptr->resize_ctl).empty_reserve          = H5C__DEF_AR_EMPTY_RESERVE;
 
     cache_ptr->epoch_markers_active = 0;
 
@@ -2705,7 +2705,7 @@ H5C_set_cache_auto_resize_config(H5C_t *cache_ptr, H5C_auto_size_ctl_t *config_p
             break;
 
         case H5C_incr__threshold:
-            if ((config_ptr->lower_hr_threshold <= (double)0.0f) || (config_ptr->increment <= (double)1.0f) ||
+            if ((config_ptr->lower_hr_threshold <= 0.0) || (config_ptr->increment <= 1.0) ||
                 ((config_ptr->apply_max_increment) && (config_ptr->max_increment <= 0)))
                 cache_ptr->size_increase_possible = FALSE;
             break;
@@ -2725,21 +2725,21 @@ H5C_set_cache_auto_resize_config(H5C_t *cache_ptr, H5C_auto_size_ctl_t *config_p
             break;
 
         case H5C_decr__threshold:
-            if ((config_ptr->upper_hr_threshold >= (double)1.0f) || (config_ptr->decrement >= (double)1.0f) ||
+            if ((config_ptr->upper_hr_threshold >= 1.0) || (config_ptr->decrement >= 1.0) ||
                 ((config_ptr->apply_max_decrement) && (config_ptr->max_decrement <= 0)))
                 cache_ptr->size_decrease_possible = FALSE;
             break;
 
         case H5C_decr__age_out:
-            if (((config_ptr->apply_empty_reserve) && (config_ptr->empty_reserve >= (double)1.0f)) ||
+            if (((config_ptr->apply_empty_reserve) && (config_ptr->empty_reserve >= 1.0)) ||
                 ((config_ptr->apply_max_decrement) && (config_ptr->max_decrement <= 0)))
                 cache_ptr->size_decrease_possible = FALSE;
             break;
 
         case H5C_decr__age_out_with_threshold:
-            if (((config_ptr->apply_empty_reserve) && (config_ptr->empty_reserve >= (double)1.0f)) ||
+            if (((config_ptr->apply_empty_reserve) && (config_ptr->empty_reserve >= 1.0)) ||
                 ((config_ptr->apply_max_decrement) && (config_ptr->max_decrement <= 0)) ||
-                (config_ptr->upper_hr_threshold >= (double)1.0f))
+                (config_ptr->upper_hr_threshold >= 1.0))
                 cache_ptr->size_decrease_possible = FALSE;
             break;
 
@@ -3720,8 +3720,7 @@ H5C_validate_resize_config(H5C_auto_size_ctl_t *config_ptr, unsigned int tests)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL,
                         "initial_size must be in the interval [min_size, max_size]")
 
-        if ((config_ptr->min_clean_fraction < (double)0.0f) ||
-            (config_ptr->min_clean_fraction > (double)1.0f))
+        if ((config_ptr->min_clean_fraction < 0.0) || (config_ptr->min_clean_fraction > 1.0))
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "min_clean_fraction must be in the interval [0.0, 1.0]")
 
         if (config_ptr->epoch_length < H5C__MIN_AR_EPOCH_LENGTH)
@@ -3736,12 +3735,11 @@ H5C_validate_resize_config(H5C_auto_size_ctl_t *config_ptr, unsigned int tests)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Invalid incr_mode")
 
         if (config_ptr->incr_mode == H5C_incr__threshold) {
-            if ((config_ptr->lower_hr_threshold < (double)0.0f) ||
-                (config_ptr->lower_hr_threshold > (double)1.0f))
+            if ((config_ptr->lower_hr_threshold < 0.0) || (config_ptr->lower_hr_threshold > 1.0))
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL,
                             "lower_hr_threshold must be in the range [0.0, 1.0]")
 
-            if (config_ptr->increment < (double)1.0f)
+            if (config_ptr->increment < 1.0)
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "increment must be greater than or equal to 1.0")
 
             /* no need to check max_increment, as it is a size_t,
@@ -3755,12 +3753,10 @@ H5C_validate_resize_config(H5C_auto_size_ctl_t *config_ptr, unsigned int tests)
                 break;
 
             case H5C_flash_incr__add_space:
-                if ((config_ptr->flash_multiple < (double)0.1f) ||
-                    (config_ptr->flash_multiple > (double)10.0f))
+                if ((config_ptr->flash_multiple < 0.1) || (config_ptr->flash_multiple > 10.0))
                     HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL,
                                 "flash_multiple must be in the range [0.1, 10.0]")
-                if ((config_ptr->flash_threshold < (double)0.1f) ||
-                    (config_ptr->flash_threshold > (double)1.0f))
+                if ((config_ptr->flash_threshold < 0.1) || (config_ptr->flash_threshold > 1.0))
                     HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL,
                                 "flash_threshold must be in the range [0.1, 1.0]")
                 break;
@@ -3781,10 +3777,10 @@ H5C_validate_resize_config(H5C_auto_size_ctl_t *config_ptr, unsigned int tests)
         }
 
         if (config_ptr->decr_mode == H5C_decr__threshold) {
-            if (config_ptr->upper_hr_threshold > (double)1.0f)
+            if (config_ptr->upper_hr_threshold > 1.0)
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "upper_hr_threshold must be <= 1.0")
 
-            if ((config_ptr->decrement > (double)1.0f) || (config_ptr->decrement < (double)0.0f))
+            if ((config_ptr->decrement > 1.0) || (config_ptr->decrement < 0.0))
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "decrement must be in the interval [0.0, 1.0]")
 
             /* no need to check max_decrement as it is a size_t
@@ -3801,7 +3797,7 @@ H5C_validate_resize_config(H5C_auto_size_ctl_t *config_ptr, unsigned int tests)
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "epochs_before_eviction too big")
 
             if ((config_ptr->apply_empty_reserve) &&
-                ((config_ptr->empty_reserve > (double)1.0f) || (config_ptr->empty_reserve < (double)0.0f)))
+                ((config_ptr->empty_reserve > 1.0) || (config_ptr->empty_reserve < 0.0)))
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "empty_reserve must be in the interval [0.0, 1.0]")
 
             /* no need to check max_decrement as it is a size_t
@@ -3810,8 +3806,7 @@ H5C_validate_resize_config(H5C_auto_size_ctl_t *config_ptr, unsigned int tests)
         } /* H5C_decr__age_out || H5C_decr__age_out_with_threshold */
 
         if (config_ptr->decr_mode == H5C_decr__age_out_with_threshold) {
-            if ((config_ptr->upper_hr_threshold > (double)1.0f) ||
-                (config_ptr->upper_hr_threshold < (double)0.0f))
+            if ((config_ptr->upper_hr_threshold > 1.0) || (config_ptr->upper_hr_threshold < 0.0))
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL,
                             "upper_hr_threshold must be in the interval [0.0, 1.0]")
         } /* H5C_decr__age_out_with_threshold */
@@ -4279,8 +4274,8 @@ H5C__auto_adjust_cache_size(H5F_t *f, hbool_t write_permitted)
     HDassert(cache_ptr);
     HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
     HDassert(cache_ptr->cache_accesses >= (cache_ptr->resize_ctl).epoch_length);
-    HDassert((double)0.0f <= (cache_ptr->resize_ctl).min_clean_fraction);
-    HDassert((cache_ptr->resize_ctl).min_clean_fraction <= (double)100.0f);
+    HDassert(0.0 <= (cache_ptr->resize_ctl).min_clean_fraction);
+    HDassert((cache_ptr->resize_ctl).min_clean_fraction <= 100.0);
 
     /* check to see if cache_ptr->resize_in_progress is TRUE.  If it, this
      * is a re-entrant call via a client callback called in the resize
@@ -4303,7 +4298,7 @@ H5C__auto_adjust_cache_size(H5F_t *f, hbool_t write_permitted)
     if (H5C_get_cache_hit_rate(cache_ptr, &hit_rate) != SUCCEED)
         HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't get hit rate")
 
-    HDassert(((double)0.0f <= hit_rate) && (hit_rate <= (double)1.0f));
+    HDassert((0.0 <= hit_rate) && (hit_rate <= 1.0));
 
     switch ((cache_ptr->resize_ctl).incr_mode) {
         case H5C_incr__off:
diff --git a/src/H5Cdbg.c b/src/H5Cdbg.c
index e59012c..104f1af 100644
--- a/src/H5Cdbg.c
+++ b/src/H5Cdbg.c
@@ -429,11 +429,11 @@ H5C_stats(H5C_t *cache_ptr, const char *cache_name,
     int32_t aggregate_max_pins             = 0;
     double  hit_rate;
     double  prefetch_use_rate;
-    double  average_successful_search_depth                   = 0.0f;
-    double  average_failed_search_depth                       = 0.0f;
-    double  average_entries_skipped_per_calls_to_msic         = 0.0f;
-    double  average_dirty_pf_entries_skipped_per_call_to_msic = 0.0f;
-    double  average_entries_scanned_per_calls_to_msic         = 0.0f;
+    double  average_successful_search_depth                   = 0.0;
+    double  average_failed_search_depth                       = 0.0;
+    double  average_entries_skipped_per_calls_to_msic         = 0.0;
+    double  average_dirty_pf_entries_skipped_per_call_to_msic = 0.0;
+    double  average_entries_scanned_per_calls_to_msic         = 0.0;
 #endif                          /* H5C_COLLECT_CACHE_STATS */
     herr_t ret_value = SUCCEED; /* Return value */
 
@@ -492,9 +492,9 @@ H5C_stats(H5C_t *cache_ptr, const char *cache_name,
     }  /* end for */
 
     if ((total_hits > 0) || (total_misses > 0))
-        hit_rate = (double)100.0f * ((double)(total_hits)) / ((double)(total_hits + total_misses));
+        hit_rate = 100.0 * ((double)(total_hits)) / ((double)(total_hits + total_misses));
     else
-        hit_rate = 0.0f;
+        hit_rate = 0.0;
 
     if (cache_ptr->successful_ht_searches > 0)
         average_successful_search_depth = ((double)(cache_ptr->total_successful_ht_search_depth)) /
@@ -630,10 +630,9 @@ H5C_stats(H5C_t *cache_ptr, const char *cache_name,
               (long long)(cache_ptr->evictions[H5AC_PREFETCHED_ENTRY_ID]));
 
     if (cache_ptr->prefetches > 0)
-        prefetch_use_rate =
-            (double)100.0f * ((double)(cache_ptr->prefetch_hits)) / ((double)(cache_ptr->prefetches));
+        prefetch_use_rate = 100.0 * ((double)(cache_ptr->prefetch_hits)) / ((double)(cache_ptr->prefetches));
     else
-        prefetch_use_rate = 0.0f;
+        prefetch_use_rate = 0.0;
 
     HDfprintf(stdout, "%s  prefetched entry use rate          = %lf\n", cache_ptr->prefix, prefetch_use_rate);
 
@@ -658,10 +657,10 @@ H5C_stats(H5C_t *cache_ptr, const char *cache_name,
                       ((cache_ptr->class_table_ptr))[i]->name);
 
             if ((cache_ptr->hits[i] > 0) || (cache_ptr->misses[i] > 0))
-                hit_rate = (double)100.0f * ((double)(cache_ptr->hits[i])) /
+                hit_rate = 100.0 * ((double)(cache_ptr->hits[i])) /
                            ((double)(cache_ptr->hits[i] + cache_ptr->misses[i]));
             else
-                hit_rate = 0.0f;
+                hit_rate = 0.0;
 
             HDfprintf(stdout, "%s    hits / misses / hit_rate       = %ld / %ld / %f\n", cache_ptr->prefix,
                       (long)(cache_ptr->hits[i]), (long)(cache_ptr->misses[i]), hit_rate);
diff --git a/src/H5Cimage.c b/src/H5Cimage.c
index 20d3b4d..f17ff48 100644
--- a/src/H5Cimage.c
+++ b/src/H5Cimage.c
@@ -933,15 +933,14 @@ H5C_image_stats(H5C_t *cache_ptr, hbool_t H5_ATTR_UNUSED print_header)
     } /* end for */
 
     if ((total_hits > 0) || (total_misses > 0))
-        hit_rate = (double)100.0f * ((double)(total_hits)) / ((double)(total_hits + total_misses));
+        hit_rate = 100.0 * ((double)(total_hits)) / ((double)(total_hits + total_misses));
     else
-        hit_rate = 0.0f;
+        hit_rate = 0.0;
 
     if (cache_ptr->prefetches > 0)
-        prefetch_use_rate =
-            (double)100.0f * ((double)(cache_ptr->prefetch_hits)) / ((double)(cache_ptr->prefetches));
+        prefetch_use_rate = 100.0 * ((double)(cache_ptr->prefetch_hits)) / ((double)(cache_ptr->prefetches));
     else
-        prefetch_use_rate = 0.0f;
+        prefetch_use_rate = 0.0;
 
     if (print_header) {
         HDfprintf(stdout, "\nhit     prefetches      prefetch              image  pf hit\n");
diff --git a/src/H5Cprivate.h b/src/H5Cprivate.h
index fb5c3ea..27a24c4 100644
--- a/src/H5Cprivate.h
+++ b/src/H5Cprivate.h
@@ -115,20 +115,20 @@
 #define H5C__CURR_CACHE_IMAGE_CTL_VER     1
 
 /* Default configuration settings */
-#define H5C__DEF_AR_UPPER_THRESHHOLD 0.9999f
-#define H5C__DEF_AR_LOWER_THRESHHOLD 0.9f
+#define H5C__DEF_AR_UPPER_THRESHHOLD 0.9999
+#define H5C__DEF_AR_LOWER_THRESHHOLD 0.9
 #define H5C__DEF_AR_MAX_SIZE         ((size_t)(16 * 1024 * 1024))
 #define H5C__DEF_AR_INIT_SIZE        ((size_t)(1 * 1024 * 1024))
 #define H5C__DEF_AR_MIN_SIZE         ((size_t)(1 * 1024 * 1024))
-#define H5C__DEF_AR_MIN_CLEAN_FRAC   0.5f
-#define H5C__DEF_AR_INCREMENT        2.0f
+#define H5C__DEF_AR_MIN_CLEAN_FRAC   0.5
+#define H5C__DEF_AR_INCREMENT        2.0
 #define H5C__DEF_AR_MAX_INCREMENT    ((size_t)(2 * 1024 * 1024))
-#define H5C__DEF_AR_FLASH_MULTIPLE   1.0f
-#define H5C__DEV_AR_FLASH_THRESHOLD  0.25f
-#define H5C__DEF_AR_DECREMENT        0.9f
+#define H5C__DEF_AR_FLASH_MULTIPLE   1.0
+#define H5C__DEV_AR_FLASH_THRESHOLD  0.25
+#define H5C__DEF_AR_DECREMENT        0.9
 #define H5C__DEF_AR_MAX_DECREMENT    ((size_t)(1 * 1024 * 1024))
 #define H5C__DEF_AR_EPCHS_B4_EVICT   3
-#define H5C__DEF_AR_EMPTY_RESERVE    0.05f
+#define H5C__DEF_AR_EMPTY_RESERVE    0.05
 #define H5C__MIN_AR_EPOCH_LENGTH     100
 #define H5C__DEF_AR_EPOCH_LENGTH     50000
 #define H5C__MAX_AR_EPOCH_LENGTH     1000000
diff --git a/src/H5HFdbg.c b/src/H5HFdbg.c
index cc61aa1..a244035 100644
--- a/src/H5HFdbg.c
+++ b/src/H5HFdbg.c
@@ -543,7 +543,7 @@ H5HF_dblock_debug(H5F_t *f, haddr_t addr, FILE *stream, int indent, int fwidth,
         amount_free = 0;
 
     HDfprintf(stream, "%*s%-*s %.2f%%\n", indent, "", fwidth, "Percent of available space for data used:",
-              ((double)100.0f * (double)((dblock->size - blk_prefix_size) - amount_free) /
+              (100.0 * (double)((dblock->size - blk_prefix_size) - amount_free) /
                (double)(dblock->size - blk_prefix_size)));
 
     /*
diff --git a/src/H5HLdbg.c b/src/H5HLdbg.c
index d0cfa96..76e4ec0 100644
--- a/src/H5HLdbg.c
+++ b/src/H5HLdbg.c
@@ -102,7 +102,7 @@ BEGIN_FUNC(PRIV, ERR, herr_t, SUCCEED, FAIL,
 
     if (h->dblk_size)
         HDfprintf(stream, "%*s%-*s %.2f%%\n", indent, "", fwidth, "Percent of heap used:",
-                  ((double)100.0f * (double)(h->dblk_size - amount_free) / (double)h->dblk_size));
+                  (100.0 * (double)(h->dblk_size - amount_free) / (double)h->dblk_size));
 
     /* Print the data in a VMS-style octal dump */
     H5_buffer_dump(stream, indent, h->dblk_image, marker, (size_t)0, h->dblk_size);
diff --git a/src/H5Pdapl.c b/src/H5Pdapl.c
index c8a97c2..2ebdbe3 100644
--- a/src/H5Pdapl.c
+++ b/src/H5Pdapl.c
@@ -768,7 +768,7 @@ H5Pset_chunk_cache(hid_t dapl_id, size_t rdcc_nslots, size_t rdcc_nbytes, double
 
     /* Check arguments.  Note that we allow negative values - they are
      * considered to "unset" the property. */
-    if (rdcc_w0 > (double)1.0f)
+    if (rdcc_w0 > 1.0)
         HGOTO_ERROR(
             H5E_ARGS, H5E_BADVALUE, FAIL,
             "raw data cache w0 value must be between 0.0 and 1.0 inclusive, or H5D_CHUNK_CACHE_W0_DEFAULT");
diff --git a/src/H5Pdxpl.c b/src/H5Pdxpl.c
index 70fc982..de67dfd 100644
--- a/src/H5Pdxpl.c
+++ b/src/H5Pdxpl.c
@@ -1486,9 +1486,8 @@ H5Pset_btree_ratios(hid_t plist_id, double left, double middle, double right)
     H5TRACE4("e", "iddd", plist_id, left, middle, right);
 
     /* Check arguments */
-    if (left < (double)0.0f || left > (double)1.0f || middle < (double)0.0f || middle > (double)1.0f ||
-        right < (double)0.0f || right > (double)1.0f)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "split ratio must satisfy 0.0<=X<=1.0")
+    if (left < 0.0 || left > 1.0 || middle < 0.0 || middle > 1.0 || right < 0.0 || right > 1.0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "split ratio must satisfy 0.0 <= X <= 1.0")
 
     /* Get the plist structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_DATASET_XFER)))
diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index fb7b195..49cc27e 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -1686,7 +1686,7 @@ H5Pset_cache(hid_t plist_id, int H5_ATTR_UNUSED mdc_nelmts, size_t rdcc_nslots,
     H5TRACE5("e", "iIszzd", plist_id, mdc_nelmts, rdcc_nslots, rdcc_nbytes, rdcc_w0);
 
     /* Check arguments */
-    if (rdcc_w0 < (double)0.0f || rdcc_w0 > (double)1.0f)
+    if (rdcc_w0 < 0.0 || rdcc_w0 > 1.0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL,
                     "raw data cache w0 value must be between 0.0 and 1.0 inclusive")
 
diff --git a/src/H5T.c b/src/H5T.c
index 666c33d..532feac 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -562,8 +562,8 @@ size_t H5T_NATIVE_UINT_FAST64_ALIGN_g  = 0;
 /* (+/- Inf for all floating-point types) */
 float  H5T_NATIVE_FLOAT_POS_INF_g  = 0.0f;
 float  H5T_NATIVE_FLOAT_NEG_INF_g  = 0.0f;
-double H5T_NATIVE_DOUBLE_POS_INF_g = (double)0.0f;
-double H5T_NATIVE_DOUBLE_NEG_INF_g = (double)0.0f;
+double H5T_NATIVE_DOUBLE_POS_INF_g = 0.0;
+double H5T_NATIVE_DOUBLE_NEG_INF_g = 0.0;
 
 /* Declare the free list for H5T_t's and H5T_shared_t's */
 H5FL_DEFINE(H5T_t);
diff --git a/src/H5Zdeflate.c b/src/H5Zdeflate.c
index d8fed41..d29d8e5 100644
--- a/src/H5Zdeflate.c
+++ b/src/H5Zdeflate.c
@@ -48,7 +48,7 @@ const H5Z_class2_t H5Z_DEFLATE[1] = {{
     H5Z__filter_deflate, /* The actual filter function	*/
 }};
 
-#define H5Z_DEFLATE_SIZE_ADJUST(s) (HDceil(((double)(s)) * (double)1.001f) + 12)
+#define H5Z_DEFLATE_SIZE_ADJUST(s) (HDceil(((double)(s)) * 1.001) + 12)
 
 /*-------------------------------------------------------------------------
  * Function:	H5Z__filter_deflate
diff --git a/src/H5Zscaleoffset.c b/src/H5Zscaleoffset.c
index 5310f7d..2e1a474 100644
--- a/src/H5Zscaleoffset.c
+++ b/src/H5Zscaleoffset.c
@@ -1116,7 +1116,7 @@ H5Z__filter_scaleoffset(unsigned flags, size_t cd_nelmts, const unsigned cd_valu
     unsigned               filavail;      /* flag indicating if fill value is defined or not */
     H5Z_SO_scale_type_t    scale_type   = H5Z_SO_FLOAT_DSCALE; /* scale type */
     int                    scale_factor = 0;                   /* scale factor */
-    double                 D_val        = 0.0f;                /* decimal scale factor */
+    double                 D_val        = 0.0;                 /* decimal scale factor */
     uint32_t               minbits      = 0;                   /* minimum number of bits to store values */
     unsigned long long     minval       = 0;                   /* minimum value of input buffer */
     enum H5Z_scaleoffset_t type;                 /* memory type corresponding to dataset datatype */
diff --git a/src/H5timer.c b/src/H5timer.c
index 54a3365..b2cc5f0 100644
--- a/src/H5timer.c
+++ b/src/H5timer.c
@@ -42,9 +42,9 @@
 #define H5TIMER_TIME_STRING_LEN 1536
 
 /* Conversion factors */
-#define H5_SEC_PER_DAY  (double)(24.0F * 60.0F * 60.0F)
-#define H5_SEC_PER_HOUR (double)(60.0F * 60.0F)
-#define H5_SEC_PER_MIN  (double)(60.0F)
+#define H5_SEC_PER_DAY  (24.0 * 60.0 * 60.0)
+#define H5_SEC_PER_HOUR (60.0 * 60.0)
+#define H5_SEC_PER_MIN  (60.0)
 
 /******************/
 /* Local Typedefs */
@@ -100,13 +100,13 @@ H5_bandwidth(char *buf /*out*/, double nbytes, double nseconds)
 {
     double bw;
 
-    if (nseconds <= (double)0.0F)
+    if (nseconds <= 0.0)
         HDstrcpy(buf, "       NaN");
     else {
         bw = nbytes / nseconds;
-        if (H5_DBL_ABS_EQUAL(bw, (double)0.0F))
+        if (H5_DBL_ABS_EQUAL(bw, 0.0))
             HDstrcpy(buf, "0.000  B/s");
-        else if (bw < (double)1.0F)
+        else if (bw < 1.0)
             HDsprintf(buf, "%10.4e", bw);
         else if (bw < (double)H5_KB) {
             HDsprintf(buf, "%05.4f", bw);
@@ -224,7 +224,7 @@ H5_now_usec(void)
 double
 H5_get_time(void)
 {
-    double ret_value = (double)0.0f;
+    double ret_value = 0.0;
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
@@ -233,14 +233,14 @@ H5_get_time(void)
         struct timespec ts;
 
         HDclock_gettime(CLOCK_MONOTONIC, &ts);
-        ret_value = (double)ts.tv_sec + ((double)ts.tv_nsec / (double)1000000000.0f);
+        ret_value = (double)ts.tv_sec + ((double)ts.tv_nsec / 1000000000.0);
     }
 #elif defined(H5_HAVE_GETTIMEOFDAY)
     {
         struct timeval now_tv;
 
         HDgettimeofday(&now_tv, NULL);
-        ret_value = (double)now_tv.tv_sec + ((double)now_tv.tv_usec / (double)1000000.0f);
+        ret_value = (double)now_tv.tv_sec + ((double)now_tv.tv_usec / 1000000.0);
     }
 #else
     ret_value = (double)HDtime(NULL);
@@ -289,8 +289,8 @@ H5__timer_get_timevals(H5_timevals_t *times /*in,out*/)
 
         if (HDgetrusage(RUSAGE_SELF, &res) < 0)
             return -1;
-        times->system = (double)res.ru_stime.tv_sec + ((double)res.ru_stime.tv_usec / (double)1.0E6F);
-        times->user   = (double)res.ru_utime.tv_sec + ((double)res.ru_utime.tv_usec / (double)1.0E6F);
+        times->system = (double)res.ru_stime.tv_sec + ((double)res.ru_stime.tv_usec / 1.0E6);
+        times->user   = (double)res.ru_utime.tv_sec + ((double)res.ru_utime.tv_usec / 1.0E6);
     }
 #else
     /* No suitable way to get system/user times */
@@ -589,7 +589,7 @@ H5_timer_get_time_string(double seconds)
     double remainder_sec = 0.0;
 
     /* Extract larger time units from count of seconds */
-    if (seconds > (double)60.0F) {
+    if (seconds > 60.0) {
         /* Set initial # of seconds */
         remainder_sec = seconds;
 
@@ -617,19 +617,19 @@ H5_timer_get_time_string(double seconds)
      * time unit.  Perhaps this could be passed as an integer.
      * (name? round_up_size? ?)
      */
-    if (seconds < (double)0.0F)
+    if (seconds < 0.0)
         HDsprintf(s, "N/A");
-    else if (H5_DBL_ABS_EQUAL((double)0.0F, seconds))
+    else if (H5_DBL_ABS_EQUAL(0.0, seconds))
         HDsprintf(s, "0.0 s");
-    else if (seconds < (double)1.0E-6F)
+    else if (seconds < 1.0E-6)
         /* t < 1 us, Print time in ns */
-        HDsprintf(s, "%.f ns", seconds * (double)1.0E9F);
-    else if (seconds < (double)1.0E-3F)
+        HDsprintf(s, "%.f ns", seconds * 1.0E9);
+    else if (seconds < 1.0E-3)
         /* t < 1 ms, Print time in us */
-        HDsprintf(s, "%.1f us", seconds * (double)1.0E6F);
-    else if (seconds < (double)1.0F)
+        HDsprintf(s, "%.1f us", seconds * 1.0E6);
+    else if (seconds < 1.0)
         /* t < 1 s, Print time in ms */
-        HDsprintf(s, "%.1f ms", seconds * (double)1.0E3F);
+        HDsprintf(s, "%.1f ms", seconds * 1.0E3);
     else if (seconds < H5_SEC_PER_MIN)
         /* t < 1 m, Print time in s */
         HDsprintf(s, "%.2f s", seconds);
diff --git a/src/H5trace.c b/src/H5trace.c
index d587853..ecb2705 100644
--- a/src/H5trace.c
+++ b/src/H5trace.c
@@ -3903,14 +3903,14 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
         if (returning) {
             if (current_depth > 1) {
                 --current_depth;
-                return (double)0.0F;
+                return 0.0;
             }
         }
         else {
             if (current_depth > 0) {
                 /* Do not update last_call_depth */
                 current_depth++;
-                return (double)0.0F;
+                return 0.0;
             }
         }
     }
@@ -3997,5 +3997,5 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
     if (H5_debug_g.ttimes)
         return function_times.elapsed;
     else
-        return (double)0.0F;
+        return 0.0;
 } /* end H5_trace() */
diff --git a/test/cache.c b/test/cache.c
index 3f2a404..0081830 100644
--- a/test/cache.c
+++ b/test/cache.c
@@ -26482,7 +26482,7 @@ check_auto_cache_resize_aux_fcns(unsigned paged)
             pass         = FALSE;
             failure_mssg = "H5C_get_cache_hit_rate failed.\n";
         }
-        else if (!H5_DBL_ABS_EQUAL(hit_rate, (double)0.0f)) { /* i.e. hit_rate != 0.0 */
+        else if (!H5_DBL_ABS_EQUAL(hit_rate, 0.0)) { /* i.e. hit_rate != 0.0 */
 
             pass         = FALSE;
             failure_mssg = "H5C_get_cache_hit_rate returned unexpected hit rate 1.\n";
@@ -26513,7 +26513,7 @@ check_auto_cache_resize_aux_fcns(unsigned paged)
             pass         = FALSE;
             failure_mssg = "H5C_get_cache_hit_rate failed.\n";
         }
-        else if (!H5_DBL_ABS_EQUAL(hit_rate, (double)0.0f)) { /* i.e. hit_rate != 0.0 */
+        else if (!H5_DBL_ABS_EQUAL(hit_rate, 0.0)) { /* i.e. hit_rate != 0.0 */
 
             pass         = FALSE;
             failure_mssg = "H5C_get_cache_hit_rate returned unexpected hit rate 2.\n";
@@ -26554,7 +26554,7 @@ check_auto_cache_resize_aux_fcns(unsigned paged)
             pass         = FALSE;
             failure_mssg = "H5C_get_cache_hit_rate failed.\n";
         }
-        else if (!H5_DBL_ABS_EQUAL(hit_rate, (double)0.5f)) { /* i.e. hit_rate != 0.5 */
+        else if (!H5_DBL_ABS_EQUAL(hit_rate, 0.5)) { /* i.e. hit_rate != 0.5 */
 
             pass         = FALSE;
             failure_mssg = "H5C_get_cache_hit_rate returned unexpected hit rate 3.\n";
@@ -26627,7 +26627,7 @@ check_auto_cache_resize_aux_fcns(unsigned paged)
             pass         = FALSE;
             failure_mssg = "H5C_get_cache_hit_rate failed.\n";
         }
-        else if (!H5_DBL_ABS_EQUAL(hit_rate, (double)0.5F)) { /* i.e. hit_rate != 0.5 */
+        else if (!H5_DBL_ABS_EQUAL(hit_rate, 0.5)) { /* i.e. hit_rate != 0.5 */
 
             pass         = FALSE;
             failure_mssg = "H5C_get_cache_hit_rate returned unexpected hit rate 4.\n";
diff --git a/test/cache_api.c b/test/cache_api.c
index 75e1b9d..5d0f395 100644
--- a/test/cache_api.c
+++ b/test/cache_api.c
@@ -81,27 +81,27 @@ check_fapl_mdc_api_calls(unsigned paged, hid_t fcpl_id)
         /* hbool_t     evictions_enabled      = */ TRUE,
         /* hbool_t     set_initial_size       = */ TRUE,
         /* size_t      initial_size           = */ (1 * 1024 * 1024 + 1),
-        /* double      min_clean_fraction     = */ 0.2f,
+        /* double      min_clean_fraction     = */ 0.2,
         /* size_t      max_size               = */ (16 * 1024 * 1024 + 1),
         /* size_t      min_size               = */ (1 * 1024 * 1024 + 1),
         /* long int    epoch_length           = */ 50001,
         /* enum H5C_cache_incr_mode incr_mode = */ H5C_incr__threshold,
-        /* double      lower_hr_threshold     = */ 0.91f,
-        /* double      increment              = */ 2.1f,
+        /* double      lower_hr_threshold     = */ 0.91,
+        /* double      increment              = */ 2.1,
         /* hbool_t     apply_max_increment    = */ TRUE,
         /* size_t      max_increment          = */ (4 * 1024 * 1024 + 1),
         /* enum H5C_cache_flash_incr_mode       */
         /*                    flash_incr_mode = */ H5C_flash_incr__off,
-        /* double      flash_multiple         = */ 2.0f,
-        /* double      flash_threshold        = */ 0.5f,
+        /* double      flash_multiple         = */ 2.0,
+        /* double      flash_threshold        = */ 0.5,
         /* enum H5C_cache_decr_mode decr_mode = */ H5C_decr__age_out,
-        /* double      upper_hr_threshold     = */ 0.998f,
-        /* double      decrement              = */ 0.91f,
+        /* double      upper_hr_threshold     = */ 0.998,
+        /* double      decrement              = */ 0.91,
         /* hbool_t     apply_max_decrement    = */ TRUE,
         /* size_t      max_decrement          = */ (1 * 1024 * 1024 - 1),
         /* int         epochs_before_eviction = */ 4,
         /* hbool_t     apply_empty_reserve    = */ TRUE,
-        /* double      empty_reserve          = */ 0.05f,
+        /* double      empty_reserve          = */ 0.05,
         /* int         dirty_bytes_threshold  = */ (256 * 1024),
         /* int        metadata_write_strategy = */
         H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
@@ -526,22 +526,22 @@ check_file_mdc_api_calls(unsigned paged, hid_t fcpl_id)
         /* hbool_t     evictions_enabled      = */ TRUE,
         /* hbool_t     set_initial_size       = */ TRUE,
         /* size_t      initial_size           = */ (1 * 1024 * 1024 + 1),
-        /* double      min_clean_fraction     = */ 0.2f,
+        /* double      min_clean_fraction     = */ 0.2,
         /* size_t      max_size               = */ (16 * 1024 * 1024 + 1),
         /* size_t      min_size               = */ (1 * 1024 * 1024 + 1),
         /* long int    epoch_length           = */ 50001,
         /* enum H5C_cache_incr_mode incr_mode = */ H5C_incr__threshold,
-        /* double      lower_hr_threshold     = */ 0.91f,
-        /* double      increment              = */ 2.1f,
+        /* double      lower_hr_threshold     = */ 0.91,
+        /* double      increment              = */ 2.1,
         /* hbool_t     apply_max_increment    = */ TRUE,
         /* size_t      max_increment          = */ (4 * 1024 * 1024 + 1),
         /* enum H5C_cache_flash_incr_mode       */
         /*                    flash_incr_mode = */ H5C_flash_incr__off,
-        /* double      flash_multiple         = */ 2.0f,
-        /* double      flash_threshold        = */ 0.5f,
+        /* double      flash_multiple         = */ 2.0,
+        /* double      flash_threshold        = */ 0.5,
         /* enum H5C_cache_decr_mode decr_mode = */ H5C_decr__age_out,
-        /* double      upper_hr_threshold     = */ 0.998f,
-        /* double      decrement              = */ 0.91f,
+        /* double      upper_hr_threshold     = */ 0.998,
+        /* double      decrement              = */ 0.91,
         /* hbool_t     apply_max_decrement    = */ TRUE,
         /* size_t      max_decrement          = */ (1 * 1024 * 1024 - 1),
         /* int         epochs_before_eviction = */ 4,
@@ -559,27 +559,27 @@ check_file_mdc_api_calls(unsigned paged, hid_t fcpl_id)
         /* hbool_t     evictions_enabled      = */ TRUE,
         /* hbool_t     set_initial_size       = */ TRUE,
         /* size_t      initial_size           = */ (512 * 1024),
-        /* double      min_clean_fraction     = */ 0.1f,
+        /* double      min_clean_fraction     = */ 0.1,
         /* size_t      max_size               = */ (8 * 1024 * 1024),
         /* size_t      min_size               = */ (512 * 1024),
         /* long int    epoch_length           = */ 25000,
         /* enum H5C_cache_incr_mode incr_mode = */ H5C_incr__threshold,
-        /* double      lower_hr_threshold     = */ 0.9f,
-        /* double      increment              = */ 2.0f,
+        /* double      lower_hr_threshold     = */ 0.9,
+        /* double      increment              = */ 2.0,
         /* hbool_t     apply_max_increment    = */ TRUE,
         /* size_t      max_increment          = */ (2 * 1024 * 1024),
         /* enum H5C_cache_flash_incr_mode       */
         /*                    flash_incr_mode = */ H5C_flash_incr__off,
-        /* double      flash_multiple         = */ 1.5f,
-        /* double      flash_threshold        = */ 0.4f,
+        /* double      flash_multiple         = */ 1.5,
+        /* double      flash_threshold        = */ 0.4,
         /* enum H5C_cache_decr_mode decr_mode = */ H5C_decr__threshold,
-        /* double      upper_hr_threshold     = */ 0.9995f,
-        /* double      decrement              = */ 0.95f,
+        /* double      upper_hr_threshold     = */ 0.9995,
+        /* double      decrement              = */ 0.95,
         /* hbool_t     apply_max_decrement    = */ TRUE,
         /* size_t      max_decrement          = */ (512 * 1024),
         /* int         epochs_before_eviction = */ 4,
         /* hbool_t     apply_empty_reserve    = */ TRUE,
-        /* double      empty_reserve          = */ 0.05f,
+        /* double      empty_reserve          = */ 0.05,
         /* int         dirty_bytes_threshold  = */ (256 * 1024),
         /* int        metadata_write_strategy = */
         H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
@@ -592,27 +592,27 @@ check_file_mdc_api_calls(unsigned paged, hid_t fcpl_id)
         /* hbool_t     evictions_enabled      = */ TRUE,
         /* hbool_t     set_initial_size       = */ TRUE,
         /* size_t      initial_size           = */ (1 * 1024 * 1024),
-        /* double      min_clean_fraction     = */ 0.2f,
+        /* double      min_clean_fraction     = */ 0.2,
         /* size_t      max_size               = */ (16 * 1024 * 1024),
         /* size_t      min_size               = */ (1 * 1024 * 1024),
         /* long int    epoch_length           = */ 50000,
         /* enum H5C_cache_incr_mode incr_mode = */ H5C_incr__off,
-        /* double      lower_hr_threshold     = */ 0.90f,
-        /* double      increment              = */ 2.0f,
+        /* double      lower_hr_threshold     = */ 0.90,
+        /* double      increment              = */ 2.0,
         /* hbool_t     apply_max_increment    = */ TRUE,
         /* size_t      max_increment          = */ (4 * 1024 * 1024),
         /* enum H5C_cache_flash_incr_mode       */
         /*                    flash_incr_mode = */ H5C_flash_incr__off,
-        /* double      flash_multiple         = */ 2.1f,
-        /* double      flash_threshold        = */ 0.6f,
+        /* double      flash_multiple         = */ 2.1,
+        /* double      flash_threshold        = */ 0.6,
         /* enum H5C_cache_decr_mode decr_mode = */ H5C_decr__off,
-        /* double      upper_hr_threshold     = */ 0.999f,
-        /* double      decrement              = */ 0.9f,
+        /* double      upper_hr_threshold     = */ 0.999,
+        /* double      decrement              = */ 0.9,
         /* hbool_t     apply_max_decrement    = */ FALSE,
         /* size_t      max_decrement          = */ (1 * 1024 * 1024 - 1),
         /* int         epochs_before_eviction = */ 3,
         /* hbool_t     apply_empty_reserve    = */ FALSE,
-        /* double      empty_reserve          = */ 0.05f,
+        /* double      empty_reserve          = */ 0.05,
         /* int         dirty_bytes_threshold  = */ (256 * 1024),
         /* int        metadata_write_strategy = */
         H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
@@ -625,28 +625,28 @@ check_file_mdc_api_calls(unsigned paged, hid_t fcpl_id)
         /* hbool_t     evictions_enabled      = */ TRUE,
         /* hbool_t     set_initial_size       = */ TRUE,
         /* size_t      initial_size           = */ (1 * 1024 * 1024),
-        /* double      min_clean_fraction     = */ 0.15f,
+        /* double      min_clean_fraction     = */ 0.15,
         /* size_t      max_size               = */ (20 * 1024 * 1024),
         /* size_t      min_size               = */ (1 * 1024 * 1024),
         /* long int    epoch_length           = */ 75000,
         /* enum H5C_cache_incr_mode incr_mode = */ H5C_incr__threshold,
-        /* double      lower_hr_threshold     = */ 0.9f,
-        /* double      increment              = */ 2.0f,
+        /* double      lower_hr_threshold     = */ 0.9,
+        /* double      increment              = */ 2.0,
         /* hbool_t     apply_max_increment    = */ TRUE,
         /* size_t      max_increment          = */ (2 * 1024 * 1024),
         /* enum H5C_cache_flash_incr_mode       */
         /*                    flash_incr_mode = */ H5C_flash_incr__off,
-        /* double      flash_multiple         = */ 1.1f,
-        /* double      flash_threshold        = */ 0.3f,
+        /* double      flash_multiple         = */ 1.1,
+        /* double      flash_threshold        = */ 0.3,
         /* enum H5C_cache_decr_mode decr_mode = */
         H5C_decr__age_out_with_threshold,
-        /* double      upper_hr_threshold     = */ 0.999f,
-        /* double      decrement              = */ 0.9f,
+        /* double      upper_hr_threshold     = */ 0.999,
+        /* double      decrement              = */ 0.9,
         /* hbool_t     apply_max_decrement    = */ TRUE,
         /* size_t      max_decrement          = */ (1 * 1024 * 1024),
         /* int         epochs_before_eviction = */ 3,
         /* hbool_t     apply_empty_reserve    = */ TRUE,
-        /* double      empty_reserve          = */ 0.1f,
+        /* double      empty_reserve          = */ 0.1,
         /* int         dirty_bytes_threshold  = */ (256 * 1024),
         /* int        metadata_write_strategy = */
         H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
@@ -755,7 +755,7 @@ check_file_mdc_api_calls(unsigned paged, hid_t fcpl_id)
             pass         = FALSE;
             failure_mssg = "H5Fget_mdc_hit_rate() failed 1.\n";
         }
-        else if (!H5_DBL_ABS_EQUAL(hit_rate, (double)0.0f)) {
+        else if (!H5_DBL_ABS_EQUAL(hit_rate, 0.0)) {
 
             pass         = FALSE;
             failure_mssg = "H5Fget_mdc_hit_rate() returned unexpected hit rate.\n";
@@ -857,7 +857,7 @@ mdc_api_call_smoke_check(int express_test, unsigned paged, hid_t fcpl_id)
     hbool_t             valid_chunk;
     hbool_t             dump_hit_rate   = FALSE;
     int64_t             min_accesses    = 1000;
-    double              min_hit_rate    = 0.90f;
+    double              min_hit_rate    = 0.90;
     hbool_t             dump_cache_size = FALSE;
     hid_t               file_id         = -1;
     hid_t               dataspace_id    = -1;
@@ -883,27 +883,27 @@ mdc_api_call_smoke_check(int express_test, unsigned paged, hid_t fcpl_id)
         /* hbool_t     evictions_enabled      = */ TRUE,
         /* hbool_t     set_initial_size       = */ TRUE,
         /* size_t      initial_size           = */ 500000,
-        /* double      min_clean_fraction     = */ 0.1f,
+        /* double      min_clean_fraction     = */ 0.1,
         /* size_t      max_size               = */ 16000000,
         /* size_t      min_size               = */ 250000,
         /* long int    epoch_length           = */ 50000,
         /* enum H5C_cache_incr_mode incr_mode = */ H5C_incr__off,
-        /* double      lower_hr_threshold     = */ 0.95f,
-        /* double      increment              = */ 2.0f,
+        /* double      lower_hr_threshold     = */ 0.95,
+        /* double      increment              = */ 2.0,
         /* hbool_t     apply_max_increment    = */ FALSE,
         /* size_t      max_increment          = */ 4000000,
         /* enum H5C_cache_flash_incr_mode       */
         /*                    flash_incr_mode = */ H5C_flash_incr__off,
-        /* double      flash_multiple         = */ 2.0f,
-        /* double      flash_threshold        = */ 0.5f,
+        /* double      flash_multiple         = */ 2.0,
+        /* double      flash_threshold        = */ 0.5,
         /* enum H5C_cache_decr_mode decr_mode = */ H5C_decr__off,
-        /* double      upper_hr_threshold     = */ 0.999f,
-        /* double      decrement              = */ 0.9f,
+        /* double      upper_hr_threshold     = */ 0.999,
+        /* double      decrement              = */ 0.9,
         /* hbool_t     apply_max_decrement    = */ FALSE,
         /* size_t      max_decrement          = */ 1000000,
         /* int         epochs_before_eviction = */ 2,
         /* hbool_t     apply_empty_reserve    = */ TRUE,
-        /* double      empty_reserve          = */ 0.05f,
+        /* double      empty_reserve          = */ 0.05,
         /* int         dirty_bytes_threshold  = */ (256 * 1024),
         /* int        metadata_write_strategy = */
         H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
@@ -916,27 +916,27 @@ mdc_api_call_smoke_check(int express_test, unsigned paged, hid_t fcpl_id)
         /* hbool_t     evictions_enabled      = */ TRUE,
         /* hbool_t     set_initial_size       = */ TRUE,
         /* size_t      initial_size           = */ 12000000,
-        /* double      min_clean_fraction     = */ 0.1f,
+        /* double      min_clean_fraction     = */ 0.1,
         /* size_t      max_size               = */ 16000000,
         /* size_t      min_size               = */ 250000,
         /* long int    epoch_length           = */ 50000,
         /* enum H5C_cache_incr_mode incr_mode = */ H5C_incr__off,
-        /* double      lower_hr_threshold     = */ 0.95f,
-        /* double      increment              = */ 2.0f,
+        /* double      lower_hr_threshold     = */ 0.95,
+        /* double      increment              = */ 2.0,
         /* hbool_t     apply_max_increment    = */ FALSE,
         /* size_t      max_increment          = */ 4000000,
         /* enum H5C_cache_flash_incr_mode       */
         /*                    flash_incr_mode = */ H5C_flash_incr__off,
-        /* double      flash_multiple         = */ 2.0f,
-        /* double      flash_threshold        = */ 0.5f,
+        /* double      flash_multiple         = */ 2.0,
+        /* double      flash_threshold        = */ 0.5,
         /* enum H5C_cache_decr_mode decr_mode = */ H5C_decr__off,
-        /* double      upper_hr_threshold     = */ 0.999f,
-        /* double      decrement              = */ 0.9f,
+        /* double      upper_hr_threshold     = */ 0.999,
+        /* double      decrement              = */ 0.9,
         /* hbool_t     apply_max_decrement    = */ FALSE,
         /* size_t      max_decrement          = */ 1000000,
         /* int         epochs_before_eviction = */ 2,
         /* hbool_t     apply_empty_reserve    = */ TRUE,
-        /* double      empty_reserve          = */ 0.05f,
+        /* double      empty_reserve          = */ 0.05,
         /* int         dirty_bytes_threshold  = */ (256 * 1024),
         /* int        metadata_write_strategy = */
         H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
@@ -949,27 +949,27 @@ mdc_api_call_smoke_check(int express_test, unsigned paged, hid_t fcpl_id)
         /* hbool_t     evictions_enabled      = */ TRUE,
         /* hbool_t     set_initial_size       = */ TRUE,
         /* size_t      initial_size           = */ 2000000,
-        /* double      min_clean_fraction     = */ 0.1f,
+        /* double      min_clean_fraction     = */ 0.1,
         /* size_t      max_size               = */ 16000000,
         /* size_t      min_size               = */ 250000,
         /* long int    epoch_length           = */ 50000,
         /* enum H5C_cache_incr_mode incr_mode = */ H5C_incr__off,
-        /* double      lower_hr_threshold     = */ 0.95f,
-        /* double      increment              = */ 2.0f,
+        /* double      lower_hr_threshold     = */ 0.95,
+        /* double      increment              = */ 2.0,
         /* hbool_t     apply_max_increment    = */ FALSE,
         /* size_t      max_increment          = */ 4000000,
         /* enum H5C_cache_flash_incr_mode       */
         /*                    flash_incr_mode = */ H5C_flash_incr__off,
-        /* double      flash_multiple         = */ 2.0f,
-        /* double      flash_threshold        = */ 0.5f,
+        /* double      flash_multiple         = */ 2.0,
+        /* double      flash_threshold        = */ 0.5,
         /* enum H5C_cache_decr_mode decr_mode = */ H5C_decr__off,
-        /* double      upper_hr_threshold     = */ 0.999f,
-        /* double      decrement              = */ 0.9f,
+        /* double      upper_hr_threshold     = */ 0.999,
+        /* double      decrement              = */ 0.9,
         /* hbool_t     apply_max_decrement    = */ FALSE,
         /* size_t      max_decrement          = */ 1000000,
         /* int         epochs_before_eviction = */ 2,
         /* hbool_t     apply_empty_reserve    = */ TRUE,
-        /* double      empty_reserve          = */ 0.05f,
+        /* double      empty_reserve          = */ 0.05,
         /* int         dirty_bytes_threshold  = */ (256 * 1024),
         /* int        metadata_write_strategy = */
         H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
@@ -1517,26 +1517,26 @@ init_invalid_configs(void)
         configs[i].evictions_enabled       = TRUE;
         configs[i].set_initial_size        = TRUE;
         configs[i].initial_size            = (1 * 1024 * 1024);
-        configs[i].min_clean_fraction      = 0.25F;
+        configs[i].min_clean_fraction      = 0.25;
         configs[i].max_size                = (16 * 1024 * 1024);
         configs[i].min_size                = (1 * 1024 * 1024);
         configs[i].epoch_length            = 50000;
         configs[i].incr_mode               = H5C_incr__threshold;
-        configs[i].lower_hr_threshold      = 0.9F;
-        configs[i].increment               = 2.0F;
+        configs[i].lower_hr_threshold      = 0.9;
+        configs[i].increment               = 2.0;
         configs[i].apply_max_increment     = TRUE;
         configs[i].max_increment           = (4 * 1024 * 1024);
         configs[i].flash_incr_mode         = H5C_flash_incr__off;
-        configs[i].flash_multiple          = 2.0F;
-        configs[i].flash_threshold         = 0.5F;
+        configs[i].flash_multiple          = 2.0;
+        configs[i].flash_threshold         = 0.5;
         configs[i].decr_mode               = H5C_decr__age_out_with_threshold;
-        configs[i].upper_hr_threshold      = 0.999F;
-        configs[i].decrement               = 0.9F;
+        configs[i].upper_hr_threshold      = 0.999;
+        configs[i].decrement               = 0.9;
         configs[i].apply_max_decrement     = TRUE;
         configs[i].max_decrement           = (1 * 1024 * 1024);
         configs[i].epochs_before_eviction  = 3;
         configs[i].apply_empty_reserve     = TRUE;
-        configs[i].empty_reserve           = 0.1F;
+        configs[i].empty_reserve           = 0.1;
         configs[i].dirty_bytes_threshold   = (256 * 1024);
         configs[i].metadata_write_strategy = H5AC__DEFAULT_METADATA_WRITE_STRATEGY;
     }
@@ -1567,10 +1567,10 @@ init_invalid_configs(void)
     configs[6].initial_size = (1 * 1024 * 1024 - 1);
 
     /* 7 -- min_clean_fraction too big */
-    configs[7].min_clean_fraction = 1.000001f;
+    configs[7].min_clean_fraction = 1.000001;
 
     /* 8 -- min_clean_fraction too small */
-    configs[8].min_clean_fraction = -0.00000001f;
+    configs[8].min_clean_fraction = -0.00000001;
 
     /* 9 -- epoch_length too small */
     configs[9].epoch_length = H5C__MIN_AR_EPOCH_LENGTH - 1;
@@ -1582,10 +1582,10 @@ init_invalid_configs(void)
     configs[11].incr_mode = (enum H5C_cache_incr_mode) - 1;
 
     /* 12 -- lower_hr_threshold too small */
-    configs[12].lower_hr_threshold = -0.000001f;
+    configs[12].lower_hr_threshold = -0.000001;
 
     /* 13 -- lower_hr_threshold too big */
-    configs[13].lower_hr_threshold = 1.00000001f;
+    configs[13].lower_hr_threshold = 1.00000001;
 
     /* 14 -- increment too small */
     configs[14].increment = 0.999999999999;
@@ -1595,29 +1595,29 @@ init_invalid_configs(void)
 
     /* 16 -- flash_multiple too small */
     configs[16].flash_incr_mode = H5C_flash_incr__add_space;
-    configs[16].flash_multiple  = 0.09f;
+    configs[16].flash_multiple  = 0.09;
 
     /* 17 -- flash_multiple too big */
     configs[17].flash_incr_mode = H5C_flash_incr__add_space;
-    configs[17].flash_multiple  = 10.001f;
+    configs[17].flash_multiple  = 10.001;
 
     /* 18 -- flash_threshold too small */
     configs[18].flash_incr_mode = H5C_flash_incr__add_space;
-    configs[18].flash_threshold = 0.099f;
+    configs[18].flash_threshold = 0.099;
 
     /* 19 -- flash_threshold too big */
     configs[19].flash_incr_mode = H5C_flash_incr__add_space;
-    configs[19].flash_threshold = 1.001f;
+    configs[19].flash_threshold = 1.001;
 
     /* 20 -- bad decr_mode */
     configs[20].decr_mode = (enum H5C_cache_decr_mode) - 1;
 
     /* 21 -- upper_hr_threshold too big */
-    configs[21].upper_hr_threshold = 1.00001f;
+    configs[21].upper_hr_threshold = 1.00001;
 
     /* 22 -- decrement too small */
     configs[22].decr_mode = H5C_decr__threshold;
-    configs[22].decrement = -0.0000000001f;
+    configs[22].decrement = -0.0000000001;
 
     /* 23 -- decrement too big */
     configs[23].decr_mode = H5C_decr__threshold;
@@ -1630,20 +1630,20 @@ init_invalid_configs(void)
     configs[25].epochs_before_eviction = H5C__MAX_EPOCH_MARKERS + 1;
 
     /* 26 -- empty_reserve too small */
-    configs[26].empty_reserve = -0.0000000001f;
+    configs[26].empty_reserve = -0.0000000001;
 
     /* 27 -- empty_reserve too big */
     configs[27].empty_reserve = 1.00000000001;
 
     /* 28 -- upper_hr_threshold too small */
-    configs[28].upper_hr_threshold = -0.000000001f;
+    configs[28].upper_hr_threshold = -0.000000001;
 
     /* 29 -- upper_hr_threshold too big */
     configs[29].upper_hr_threshold = 1.00000001;
 
     /* 30 -- upper_hr_threshold <= lower_hr_threshold */
-    configs[30].lower_hr_threshold = 0.9f;
-    configs[30].upper_hr_threshold = 0.9f;
+    configs[30].lower_hr_threshold = 0.9;
+    configs[30].upper_hr_threshold = 0.9;
 
     /* 31 -- dirty_bytes_threshold too small */
     configs[31].dirty_bytes_threshold = (H5C__MIN_MAX_CACHE_SIZE / 2) - 1;
diff --git a/test/cross_read.c b/test/cross_read.c
index 386c0da..eef814f 100644
--- a/test/cross_read.c
+++ b/test/cross_read.c
@@ -159,9 +159,9 @@ check_data_f(const char *dsetname, hid_t fid)
     /* Input (last row is different) */
     for (i = 0; i < NX; i++)
         for (j = 0; j < NY; j++)
-            data_in[i][j] = ((double)(i + j + 1)) / (double)3.0F;
+            data_in[i][j] = ((double)(i + j + 1)) / 3.0;
     for (i = 0; i < NY; i++)
-        data_in[NX][i] = -2.2F;
+        data_in[NX][i] = -2.2;
     /* Output */
     HDmemset(data_out, 0, (NX + 1) * NY * sizeof(double));
 
@@ -174,7 +174,7 @@ check_data_f(const char *dsetname, hid_t fid)
     /* Check results */
     for (i = 0; i < (NX + 1); i++)
         for (j = 0; j < NY; j++)
-            if (!H5_DBL_REL_EQUAL(data_out[i][j], data_in[i][j], (double)0.001F))
+            if (!H5_DBL_REL_EQUAL(data_out[i][j], data_in[i][j], 0.001))
                 if (!nerrors++) {
                     H5_FAILED();
                     HDprintf("element [%d][%d] is %g but should have been %g\n", (int)i, (int)j,
diff --git a/test/dsets.c b/test/dsets.c
index e38f253..88dcb35 100644
--- a/test/dsets.c
+++ b/test/dsets.c
@@ -6520,7 +6520,7 @@ test_set_local(hid_t fapl)
     for (i = 0; i < DSET_DIM1; i++)
         for (j = 0; j < DSET_DIM2; j++) {
             points[i][j]     = (int)n++;
-            points_dbl[i][j] = (double)1.5F * n++;
+            points_dbl[i][j] = 1.5 * n++;
         }
 
     /* Open file */
@@ -6716,7 +6716,7 @@ test_set_local(hid_t fapl)
         for (j = 0; j < dims[1]; j++) {
             /* If the difference between two values is greater than 0.001%, they're
              * considered not equal. */
-            if (!H5_DBL_REL_EQUAL(points_dbl[i][j], check_dbl[i][j], (double)0.00001F)) {
+            if (!H5_DBL_REL_EQUAL(points_dbl[i][j], check_dbl[i][j], 0.00001)) {
                 H5_FAILED();
                 HDprintf("    Line %d: Read different values than written.\n", __LINE__);
                 HDprintf("    At index %lu,%lu\n", (unsigned long)(i), (unsigned long)(j));
@@ -8803,7 +8803,7 @@ test_chunk_cache(hid_t fapl)
     /* Set new rdcc settings on fapl */
     nslots_2 = nslots_1 * 2;
     nbytes_2 = nbytes_1 * 2;
-    w0_2     = w0_1 / (double)2.0F;
+    w0_2     = w0_1 / 2.0;
     if (H5Pset_cache(fapl_local, 0, nslots_2, nbytes_2, w0_2) < 0)
         FAIL_STACK_ERROR
 
diff --git a/test/dt_arith.c b/test/dt_arith.c
index ddc8814..7b79102 100644
--- a/test/dt_arith.c
+++ b/test/dt_arith.c
@@ -3232,7 +3232,7 @@ test_conv_flt_1(const char *name, int run_test, hid_t src, hid_t dst)
                 int expo_diff = check_expo[0] - check_expo[1];
                 int valid_bits =
                     (int)((dst_ebias + dst_msize) + (size_t)MIN(check_expo[0], check_expo[1])) - 1;
-                double epsilon = 1.0F;
+                double epsilon = 1.0;
 
                 /* Re-scale the mantissas based on any exponent difference */
                 if (expo_diff != 0)
diff --git a/test/dtypes.c b/test/dtypes.c
index 626c58c..52eb0ea 100644
--- a/test/dtypes.c
+++ b/test/dtypes.c
@@ -2284,9 +2284,9 @@ test_compound_11(void)
 
     /* Initialize buffer */
     for (u = 0; u < NTESTELEM; u++) {
-        ((big_t *)buf)[u].d1 = (double)u * (double)1.5f;
-        ((big_t *)buf)[u].d2 = (double)u * (double)2.5f;
-        ((big_t *)buf)[u].d3 = (double)u * (double)3.5f;
+        ((big_t *)buf)[u].d1 = (double)u * 1.5;
+        ((big_t *)buf)[u].d2 = (double)u * 2.5;
+        ((big_t *)buf)[u].d3 = (double)u * 3.5;
         ((big_t *)buf)[u].i1 = (int)(u * 3);
         ((big_t *)buf)[u].i2 = (int)(u * 5);
         ((big_t *)buf)[u].s1 = (char *)HDmalloc((size_t)32);
diff --git a/test/enc_dec_plist.c b/test/enc_dec_plist.c
index 83298c8..9b4879e 100644
--- a/test/enc_dec_plist.c
+++ b/test/enc_dec_plist.c
@@ -141,11 +141,11 @@ main(void)
     hid_t        vspace        = -1;         /* Virtual dset dataspaces */
     hsize_t      dims[1]       = {3};        /* Data space current size */
     hsize_t      chunk_size[2] = {16384, 4}; /* chunk size */
-    double       fill          = 2.7f;       /* Fill value */
+    double       fill          = 2.7;        /* Fill value */
     hsize_t      max_size[1];                /* data space maximum size */
     size_t       nslots = 521 * 2;
     size_t       nbytes = 1048576 * 10;
-    double       w0     = 0.5f;
+    double       w0     = 0.5;
     unsigned     max_compact;
     unsigned     min_dense;
     const char * c_to_f = "x+32";
@@ -159,26 +159,26 @@ main(void)
                                            TRUE,
                                            FALSE,
                                            (2 * 2048 * 1024),
-                                           0.3f,
+                                           0.3,
                                            (64 * 1024 * 1024),
                                            (4 * 1024 * 1024),
                                            60000,
                                            H5C_incr__threshold,
-                                           0.8f,
-                                           3.0f,
+                                           0.8,
+                                           3.0,
                                            TRUE,
                                            (8 * 1024 * 1024),
                                            H5C_flash_incr__add_space,
-                                           2.0f,
-                                           0.25f,
+                                           2.0,
+                                           0.25,
                                            H5C_decr__age_out_with_threshold,
-                                           0.997f,
-                                           0.8f,
+                                           0.997,
+                                           0.8,
                                            TRUE,
                                            (3 * 1024 * 1024),
                                            3,
                                            FALSE,
-                                           0.2f,
+                                           0.2,
                                            (256 * 2048),
                                            H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
 
diff --git a/test/gen_cross.c b/test/gen_cross.c
index 3eac79a..2746bb6 100644
--- a/test/gen_cross.c
+++ b/test/gen_cross.c
@@ -295,7 +295,7 @@ create_scale_offset_dsets_double(hid_t fid, hid_t fsid, hid_t msid)
     hid_t   dataset = -1; /* dataset handles */
     hid_t   dcpl    = -1;
     double  data[NX][NY]; /* data to write */
-    double  fillvalue   = -2.2f;
+    double  fillvalue   = -2.2;
     hsize_t chunk[RANK] = {CHUNK0, CHUNK1};
     int     i, j;
 
diff --git a/test/gen_plist.c b/test/gen_plist.c
index 7a67c56..10c6423 100644
--- a/test/gen_plist.c
+++ b/test/gen_plist.c
@@ -42,7 +42,7 @@ main(void)
     hsize_t                   max_size[1];        /* data space maximum size */
     size_t                    nslots = 521 * 2;
     size_t                    nbytes = 1048576 * 10;
-    double                    w0     = 0.5f;
+    double                    w0     = 0.5;
     unsigned                  max_compact;
     unsigned                  min_dense;
     const char *              c_to_f = "x+32";
@@ -56,26 +56,26 @@ main(void)
                                            1 /*TRUE*/,
                                            0 /*FALSE*/,
                                            (2 * 2048 * 1024),
-                                           0.3f,
+                                           0.3,
                                            (64 * 1024 * 1024),
                                            (4 * 1024 * 1024),
                                            60000,
                                            H5C_incr__threshold,
-                                           0.8f,
-                                           3.0f,
+                                           0.8,
+                                           3.0,
                                            1 /*TRUE*/,
                                            (8 * 1024 * 1024),
                                            H5C_flash_incr__add_space,
-                                           2.0f,
-                                           0.25f,
+                                           2.0,
+                                           0.25,
                                            H5C_decr__age_out_with_threshold,
-                                           0.997f,
-                                           0.8f,
+                                           0.997,
+                                           0.8,
                                            1 /*TRUE*/,
                                            (3 * 1024 * 1024),
                                            3,
                                            0 /*FALSE*/,
-                                           0.2f,
+                                           0.2,
                                            (256 * 2048),
                                            H5AC_METADATA_WRITE_STRATEGY__PROCESS_0_ONLY};
     H5AC_cache_image_config_t my_cache_image_config = {H5AC__CURR_CACHE_IMAGE_CONFIG_VERSION, TRUE, FALSE,
diff --git a/test/links.c b/test/links.c
index 2ac2e28..b2d0d9a 100644
--- a/test/links.c
+++ b/test/links.c
@@ -140,7 +140,7 @@ const char *FILENAME[] = {"links0",
 #define H5L_DIM1 100
 #define H5L_DIM2 100
 
-#define FILTER_FILESIZE_MAX_FRACTION (double)0.9F
+#define FILTER_FILESIZE_MAX_FRACTION 0.9
 
 /* Creation order macros */
 #define CORDER_GROUP_NAME      "corder_group"
diff --git a/test/mtime.c b/test/mtime.c
index 78f9065..43dc502 100644
--- a/test/mtime.c
+++ b/test/mtime.c
@@ -120,7 +120,7 @@ main(void)
         HDputs("    cannot be queried on this system.  See H5O_mtime_decode().");
         return 0;
     }
-    else if (HDfabs(HDdifftime(now, oi1.ctime)) > (double)60.0F) {
+    else if (HDfabs(HDdifftime(now, oi1.ctime)) > 60.0) {
         H5_FAILED();
         tm = HDlocaltime(&(oi1.ctime));
         HDstrftime((char *)buf1, sizeof buf1, "%Y-%m-%d %H:%M:%S", tm);
diff --git a/test/objcopy.c b/test/objcopy.c
index 681b8a5..43a5756 100644
--- a/test/objcopy.c
+++ b/test/objcopy.c
@@ -2936,7 +2936,7 @@ test_copy_dataset_compound(hid_t fcpl_src, hid_t fcpl_dst, hid_t src_fapl, hid_t
     HDmemset(buf, 0, sizeof(buf));
     for (i = 0; i < DIM_SIZE_1; i++) {
         buf[i].a = i;
-        buf[i].d = (double)1.0F / (double)(i + 1);
+        buf[i].d = 1.0 / (double)(i + 1);
     } /* end for */
 
     /* Initialize the filenames */
diff --git a/test/tattr.c b/test/tattr.c
index 3f0c102..b602222 100644
--- a/test/tattr.c
+++ b/test/tattr.c
@@ -519,13 +519,13 @@ test_attr_basic_read(hid_t fapl)
 static void
 test_attr_flush(hid_t fapl)
 {
-    hid_t fil,               /* File ID */
-        att,                 /* Attribute ID */
-        spc,                 /* Dataspace ID */
-        set;                 /* Dataset ID */
-    double wdata = 3.14159F; /* Data to write */
-    double rdata;            /* Data read in */
-    herr_t ret;              /* Generic return value        */
+    hid_t fil,              /* File ID */
+        att,                /* Attribute ID */
+        spc,                /* Dataspace ID */
+        set;                /* Dataset ID */
+    double wdata = 3.14159; /* Data to write */
+    double rdata;           /* Data read in */
+    herr_t ret;             /* Generic return value */
 
     /* Output message about test being performed */
     MESSAGE(5, ("Testing Attribute Flushing\n"));
@@ -545,8 +545,8 @@ test_attr_flush(hid_t fapl)
     ret = H5Aread(att, H5T_NATIVE_DOUBLE, &rdata);
     CHECK(ret, FAIL, "H5Awrite");
 
-    if (!H5_DBL_ABS_EQUAL(rdata, (double)0.0f))
-        TestErrPrintf("attribute value wrong: rdata=%f, should be %f\n", rdata, (double)0.0F);
+    if (!H5_DBL_ABS_EQUAL(rdata, 0.0))
+        TestErrPrintf("attribute value wrong: rdata=%f, should be %f\n", rdata, 0.0);
 
     ret = H5Fflush(fil, H5F_SCOPE_GLOBAL);
     CHECK(ret, FAIL, "H5Fflush");
@@ -554,8 +554,8 @@ test_attr_flush(hid_t fapl)
     ret = H5Aread(att, H5T_NATIVE_DOUBLE, &rdata);
     CHECK(ret, FAIL, "H5Awrite");
 
-    if (!H5_DBL_ABS_EQUAL(rdata, (double)0.0f))
-        TestErrPrintf("attribute value wrong: rdata=%f, should be %f\n", rdata, (double)0.0F);
+    if (!H5_DBL_ABS_EQUAL(rdata, 0.0))
+        TestErrPrintf("attribute value wrong: rdata=%f, should be %f\n", rdata, 0.0);
 
     ret = H5Awrite(att, H5T_NATIVE_DOUBLE, &wdata);
     CHECK(ret, FAIL, "H5Awrite");
diff --git a/test/tgenprop.c b/test/tgenprop.c
index 7e805e2..55e5a9b 100644
--- a/test/tgenprop.c
+++ b/test/tgenprop.c
@@ -55,7 +55,7 @@ char prop3_def[10] = "Ten chars"; /* Property 3 default value */
 #define PROP3_DEF_VALUE (&prop3_def)
 
 #define PROP4_NAME "Property 4"
-double prop4_def = 1.41F; /* Property 4 default value */
+double prop4_def = 1.41; /* Property 4 default value */
 #define PROP4_SIZE      sizeof(prop4_def)
 #define PROP4_DEF_VALUE (&prop4_def)
 
diff --git a/test/th5s.c b/test/th5s.c
index 30c3396..51216dc 100644
--- a/test/th5s.c
+++ b/test/th5s.c
@@ -2575,7 +2575,7 @@ test_h5s_chunk(void)
     for (i = 0; i < CHUNK_DATA_NX; i++) {
         for (j = 0; j < CHUNK_DATA_NY; j++) {
             /* Check if the two values are within 0.001% range. */
-            if (!H5_DBL_REL_EQUAL(chunk_data_dbl[i][j], (double)chunk_data_flt[i][j], (double)0.00001F))
+            if (!H5_DBL_REL_EQUAL(chunk_data_dbl[i][j], (double)chunk_data_flt[i][j], 0.00001))
                 TestErrPrintf("%u: chunk_data_dbl[%d][%d]=%e, chunk_data_flt[%d][%d]=%e\n",
                               (unsigned)__LINE__, i, j, chunk_data_dbl[i][j], i, j,
                               (double)chunk_data_flt[i][j]);
diff --git a/test/timer.c b/test/timer.c
index 24f3245..bb474ca 100644
--- a/test/timer.c
+++ b/test/timer.c
@@ -144,7 +144,7 @@ test_timer_system_user(void)
     /* The system and user times may not be present on some systems.  They
      * will be -1.0 if they are not.
      */
-    if (timer.initial.system < (double)0.0f || timer.initial.user < (double)0.0f) {
+    if (timer.initial.system < 0.0 || timer.initial.user < 0.0) {
         SKIPPED();
         HDprintf("NOTE: No suitable way to get system/user times on this platform.\n");
         return 0;
@@ -165,7 +165,7 @@ test_timer_system_user(void)
         TEST_ERROR;
 
     /* System and user times should be non-negative. */
-    if (times.system < (double)0.0f || times.user < (double)0.0f)
+    if (times.system < 0.0 || times.user < 0.0)
         TEST_ERROR;
 
     PASSED();
@@ -224,7 +224,7 @@ test_timer_elapsed(void)
         TEST_ERROR;
 
     /* Elapsed time should be non-negative. */
-    if (times.elapsed < (double)0.0f)
+    if (times.elapsed < 0.0)
         TEST_ERROR;
 
     PASSED();
@@ -260,11 +260,11 @@ test_timer_functionality(void)
 
     /* Times should be initialized to zero */
     err = H5_timer_get_times(timer, &times);
-    if (err < 0 || !H5_DBL_ABS_EQUAL(times.elapsed, (double)0.0f))
+    if (err < 0 || !H5_DBL_ABS_EQUAL(times.elapsed, 0.0))
         TEST_ERROR;
 
     err = H5_timer_get_total_times(timer, &times);
-    if (err < 0 || !H5_DBL_ABS_EQUAL(times.elapsed, (double)0.0f))
+    if (err < 0 || !H5_DBL_ABS_EQUAL(times.elapsed, 0.0))
         TEST_ERROR;
 
     /********************
@@ -289,11 +289,11 @@ test_timer_functionality(void)
 
     /* Times should be positive and non-negative */
     err = H5_timer_get_times(timer, &times);
-    if (err < 0 || times.elapsed < (double)0.0f)
+    if (err < 0 || times.elapsed < 0.0)
         TEST_ERROR;
 
     err = H5_timer_get_total_times(timer, &times);
-    if (err < 0 || times.elapsed < (double)0.0f)
+    if (err < 0 || times.elapsed < 0.0)
         TEST_ERROR;
 
     /**********************
@@ -306,11 +306,11 @@ test_timer_functionality(void)
         TEST_ERROR;
 
     err = H5_timer_get_times(timer, &times);
-    if (err < 0 || !H5_DBL_ABS_EQUAL(times.elapsed, (double)0.0f))
+    if (err < 0 || !H5_DBL_ABS_EQUAL(times.elapsed, 0.0))
         TEST_ERROR;
 
     err = H5_timer_get_total_times(timer, &times);
-    if (err < 0 || !H5_DBL_ABS_EQUAL(times.elapsed, (double)0.0f))
+    if (err < 0 || !H5_DBL_ABS_EQUAL(times.elapsed, 0.0))
         TEST_ERROR;
 
     /* Timer state should flip */
@@ -326,12 +326,12 @@ test_timer_functionality(void)
 
     /* Times should be non-negative */
     err = H5_timer_get_times(timer, &times);
-    if (err < 0 || times.elapsed < (double)0.0f)
+    if (err < 0 || times.elapsed < 0.0)
         TEST_ERROR;
     prev_etime = times.elapsed;
 
     err = H5_timer_get_total_times(timer, &times);
-    if (err < 0 || times.elapsed < (double)0.0f)
+    if (err < 0 || times.elapsed < 0.0)
         TEST_ERROR;
     prev_total_etime = times.elapsed;
 
diff --git a/test/tmisc.c b/test/tmisc.c
index 51e203a..302da0d 100644
--- a/test/tmisc.c
+++ b/test/tmisc.c
@@ -2521,17 +2521,17 @@ test_misc13(void)
 static void
 test_misc14(void)
 {
-    hid_t  file_id;       /* File ID */
-    hid_t  fapl;          /* File access property list ID */
-    hid_t  DataSpace;     /* Dataspace ID */
-    hid_t  Dataset1;      /* Dataset ID #1 */
-    hid_t  Dataset2;      /* Dataset ID #2 */
-    hid_t  Dataset3;      /* Dataset ID #3 */
-    double data1 = 5.0F;  /* Data to write for dataset #1 */
-    double data2 = 10.0F; /* Data to write for dataset #2 */
-    double data3 = 15.0F; /* Data to write for dataset #3 */
-    double rdata;         /* Data read in */
-    herr_t ret;           /* Generic return value */
+    hid_t  file_id;      /* File ID */
+    hid_t  fapl;         /* File access property list ID */
+    hid_t  DataSpace;    /* Dataspace ID */
+    hid_t  Dataset1;     /* Dataset ID #1 */
+    hid_t  Dataset2;     /* Dataset ID #2 */
+    hid_t  Dataset3;     /* Dataset ID #3 */
+    double data1 = 5.0;  /* Data to write for dataset #1 */
+    double data2 = 10.0; /* Data to write for dataset #2 */
+    double data3 = 15.0; /* Data to write for dataset #3 */
+    double rdata;        /* Data read in */
+    herr_t ret;          /* Generic return value */
 
     /* Test creating two datasets and deleting the second */
 
diff --git a/testpar/t_prop.c b/testpar/t_prop.c
index 92c8bc0..a3f1859 100644
--- a/testpar/t_prop.c
+++ b/testpar/t_prop.c
@@ -98,10 +98,10 @@ test_plist_ed(void)
     int mpi_size, mpi_rank, recv_proc;
 
     hsize_t             chunk_size = 16384; /* chunk size */
-    double              fill       = 2.7f;  /* Fill value */
+    double              fill       = 2.7;   /* Fill value */
     size_t              nslots     = 521 * 2;
     size_t              nbytes     = 1048576 * 10;
-    double              w0         = 0.5f;
+    double              w0         = 0.5;
     unsigned            max_compact;
     unsigned            min_dense;
     hsize_t             max_size[1]; /*data space maximum size */
@@ -114,26 +114,26 @@ test_plist_ed(void)
                                            TRUE,
                                            FALSE,
                                            (2 * 2048 * 1024),
-                                           0.3f,
+                                           0.3,
                                            (64 * 1024 * 1024),
                                            (4 * 1024 * 1024),
                                            60000,
                                            H5C_incr__threshold,
-                                           0.8f,
-                                           3.0f,
+                                           0.8,
+                                           3.0,
                                            TRUE,
                                            (8 * 1024 * 1024),
                                            H5C_flash_incr__add_space,
-                                           2.0f,
-                                           0.25f,
+                                           2.0,
+                                           0.25,
                                            H5C_decr__age_out_with_threshold,
-                                           0.997f,
-                                           0.8f,
+                                           0.997,
+                                           0.8,
                                            TRUE,
                                            (3 * 1024 * 1024),
                                            3,
                                            FALSE,
-                                           0.2f,
+                                           0.2,
                                            (256 * 2048),
                                            H5AC__DEFAULT_METADATA_WRITE_STRATEGY};
 
diff --git a/tools/src/h5diff/h5diff_common.c b/tools/src/h5diff/h5diff_common.c
index 603b1f3..1b81824 100644
--- a/tools/src/h5diff/h5diff_common.c
+++ b/tools/src/h5diff/h5diff_common.c
@@ -375,7 +375,7 @@ parse_command_line(int argc, const char *argv[], const char **fname1, const char
                 opts->percent = HDatof(opt_arg);
 
                 /* -p 0 is the same as default */
-                if (H5_DBL_ABS_EQUAL(opts->percent, (double)0.0F))
+                if (H5_DBL_ABS_EQUAL(opts->percent, 0.0))
                     opts->percent_bool = 0;
                 break;
 
diff --git a/tools/src/h5ls/h5ls.c b/tools/src/h5ls/h5ls.c
index a0b9441..4392d85 100644
--- a/tools/src/h5ls/h5ls.c
+++ b/tools/src/h5ls/h5ls.c
@@ -1983,7 +1983,7 @@ dataset_list2(hid_t dset, const char H5_ATTR_UNUSED *name)
                                    HSIZE_T_FORMAT " logical byte%s, " HSIZE_T_FORMAT " allocated byte%s",
                                    total, 1 == total ? "" : "s", used, 1 == used ? "" : "s");
                 if (used > 0) {
-                    utilization = ((double)total * (double)100.0f) / (double)used;
+                    utilization = ((double)total * 100.0) / (double)used;
                     h5tools_str_append(&buffer, ", %1.2f%% utilization", utilization);
                 }
         }
diff --git a/tools/src/h5stat/h5stat.c b/tools/src/h5stat/h5stat.c
index 3e7a8c1..e091a8a 100644
--- a/tools/src/h5stat/h5stat.c
+++ b/tools/src/h5stat/h5stat.c
@@ -1609,7 +1609,7 @@ print_storage_summary(const iter_t *iter)
 {
     hsize_t total_meta = 0;
     hsize_t unaccount  = 0;
-    double  percent    = 0.0f;
+    double  percent    = 0.0;
 
     HDfprintf(stdout, "File space management strategy: %s\n", FS_STRATEGY_NAME[iter->fs_strategy]);
     HDfprintf(stdout, "File space page size: %" PRIuHSIZE " bytes\n", iter->fsp_size);
@@ -1624,7 +1624,7 @@ print_storage_summary(const iter_t *iter)
     HDfprintf(stdout, "  File metadata: %" PRIuHSIZE " bytes\n", total_meta);
     HDfprintf(stdout, "  Raw data: %" PRIuHSIZE " bytes\n", iter->dset_storage_size);
 
-    percent = ((double)iter->free_space / (double)iter->filesize) * (double)100.0f;
+    percent = ((double)iter->free_space / (double)iter->filesize) * 100.0;
     HDfprintf(stdout, "  Amount/Percent of tracked free space: %" PRIuHSIZE " bytes/%3.1f%%\n",
               iter->free_space, percent);
 
diff --git a/tools/test/h5import/h5importtest.c b/tools/test/h5import/h5importtest.c
index 340e31b..e49125b 100644
--- a/tools/test/h5import/h5importtest.c
+++ b/tools/test/h5import/h5importtest.c
@@ -64,8 +64,8 @@ main(void)
 
     double b64r3[5][3][4];
     double row8[3], col8[4], pln8[5];
-    double rowo8 = 11.0F, colo8 = 21.0F, plno8 = 51.0F;
-    double rowi8 = 1.0F, coli8 = 2.0F, plni8 = 5.0F;
+    double rowo8 = 11.0, colo8 = 21.0, plno8 = 51.0;
+    double rowi8 = 1.0, coli8 = 2.0, plni8 = 5.0;
 
     /* Initialize machine endian */
     volatile uint32_t ibyte = 0x01234567;
diff --git a/tools/test/perform/chunk.c b/tools/test/perform/chunk.c
index ada2ed3..1b6793a 100644
--- a/tools/test/perform/chunk.c
+++ b/tools/test/perform/chunk.c
@@ -55,20 +55,20 @@
 #define RM_CACHE_STRT 25
 #define RM_CACHE_END  25
 #define RM_CACHE_DELT 5
-#define RM_START      (double)0.50F
-#define RM_END        (double)5.00F
-#define RM_DELTA      (double)0.50F
-#define RM_W0         0.0F
+#define RM_START      0.50
+#define RM_END        5.00
+#define RM_DELTA      0.50
+#define RM_W0         0.0
 #define RM_NRDCC      521
 
 /* Diagonal test */
 #define DIAG_CACHE_STRT 25
 #define DIAG_CACHE_END  25
 #define DIAG_CACHE_DELT 5
-#define DIAG_START      (double)0.50F
-#define DIAG_END        (double)5.00F
-#define DIAG_DELTA      (double)0.50F
-/* #define DIAG_W0		0.65F */
+#define DIAG_START      0.50
+#define DIAG_END        5.00
+#define DIAG_DELTA      0.50
+/* #define DIAG_W0		0.65 */
 /* #define DIAG_NRDCC		521 */
 
 static size_t nio_g;
diff --git a/tools/test/perform/chunk_cache.c b/tools/test/perform/chunk_cache.c
index fcaa337..25fa34c 100644
--- a/tools/test/perform/chunk_cache.c
+++ b/tools/test/perform/chunk_cache.c
@@ -262,13 +262,14 @@ check_partial_chunks_perf(hid_t file)
 
     end_t = H5_get_time();
 
-    if ((end_t - start_t) > (double)0.0f)
-        printf("1. Partial chunks: total read time is %lf; number of bytes being read from file is %zu\n",
-               (end_t - start_t), nbytes_global);
+    if ((end_t - start_t) > 0.0)
+        HDprintf("1. Partial chunks: total read time is %lf; number of bytes being read from file is %zu\n",
+                 (end_t - start_t), nbytes_global);
     else
-        printf("1. Partial chunks: no total read time because timer is not available; number of bytes being "
-               "read from file is %zu\n",
-               nbytes_global);
+        HDprintf(
+            "1. Partial chunks: no total read time because timer is not available; number of bytes being "
+            "read from file is %zu\n",
+            nbytes_global);
 
     H5Dclose(dataset);
     H5Sclose(filespace);
@@ -340,13 +341,14 @@ check_hash_value_perf(hid_t file)
 
     end_t = H5_get_time();
 
-    if ((end_t - start_t) > (double)0.0f)
-        printf("2. Hash value: total read time is %lf; number of bytes being read from file is %zu\n",
-               (end_t - start_t), nbytes_global);
+    if ((end_t - start_t) > 0.0)
+        HDprintf("2. Hash value: total read time is %lf; number of bytes being read from file is %zu\n",
+                 (end_t - start_t), nbytes_global);
     else
-        printf("2. Hash value: no total read time because timer is not available; number of bytes being read "
-               "from file is %zu\n",
-               nbytes_global);
+        HDprintf(
+            "2. Hash value: no total read time because timer is not available; number of bytes being read "
+            "from file is %zu\n",
+            nbytes_global);
 
     H5Dclose(dataset);
     H5Sclose(filespace);
@@ -375,7 +377,7 @@ error:
 int
 main(void)
 {
-    hid_t file; /* handles */
+    hid_t file    = H5I_INVALID_HID; /* file ID */
     int   nerrors = 0;
 
     /* Create a new file. If file exists its contents will be overwritten. */
@@ -404,6 +406,6 @@ main(void)
     return 0;
 
 error:
-    fprintf(stderr, "*** ERRORS DETECTED ***\n");
+    HDfprintf(stderr, "*** ERRORS DETECTED ***\n");
     return 1;
 }
diff --git a/tools/test/perform/iopipe.c b/tools/test/perform/iopipe.c
index 68eaa3a..d0db06a 100644
--- a/tools/test/perform/iopipe.c
+++ b/tools/test/perform/iopipe.c
@@ -64,11 +64,11 @@ print_stats(const char *prefix,
 #ifdef H5_HAVE_GETRUSAGE
     double u_time, s_time;
 
-    u_time = ((double)(r_stop->ru_utime.tv_sec) + (double)(r_stop->ru_utime.tv_usec) / (double)1000000.0F) -
-             ((double)(r_start->ru_utime.tv_sec) + (double)(r_start->ru_utime.tv_usec) / (double)1000000.0F);
+    u_time = ((double)(r_stop->ru_utime.tv_sec) + (double)(r_stop->ru_utime.tv_usec) / 1000000.0) -
+             ((double)(r_start->ru_utime.tv_sec) + (double)(r_start->ru_utime.tv_usec) / 1000000.0);
 
-    s_time = ((double)(r_stop->ru_stime.tv_sec) + (double)(r_stop->ru_stime.tv_usec) / (double)1000000.0F) -
-             ((double)(r_start->ru_stime.tv_sec) + (double)(r_start->ru_stime.tv_usec) / (double)1000000.0F);
+    s_time = ((double)(r_stop->ru_stime.tv_sec) + (double)(r_stop->ru_stime.tv_usec) / 1000000.0) -
+             ((double)(r_start->ru_stime.tv_sec) + (double)(r_start->ru_stime.tv_usec) / 1000000.0);
 #endif
     e_time = t_stop - t_start;
     H5_bandwidth(bw, (double)nbytes, e_time);
@@ -149,8 +149,7 @@ main(void)
      * Win32 version 5.0 compiler.
      * 1998-11-06 ptl
      */
-    HDprintf("I/O request size is %1.1fMB\n",
-             (double)(hssize_t)(size[0] * size[1]) / (double)1024.0F * (double)1024);
+    HDprintf("I/O request size is %1.1fMB\n", (double)(hssize_t)(size[0] * size[1]) / 1024.0 * 1024.0);
 
     /* Open the files */
     file = H5Fcreate(HDF5_FILE_NAME, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
diff --git a/tools/test/perform/sio_perf.c b/tools/test/perform/sio_perf.c
index 5b3a9e8..fe4e7e7 100644
--- a/tools/test/perform/sio_perf.c
+++ b/tools/test/perform/sio_perf.c
@@ -65,8 +65,7 @@
 #define SIO_HDF5  0x4
 
 /* report 0.0 in case t is zero too */
-#define MB_PER_SEC(bytes, t)                                                                                 \
-    (H5_DBL_ABS_EQUAL(t, (double)0.0F) ? (double)0.0F : ((((double)bytes) / (double)ONE_MB) / (t)))
+#define MB_PER_SEC(bytes, t) (H5_DBL_ABS_EQUAL(t, 0.0) ? 0.0 : ((((double)bytes) / (double)ONE_MB) / (t)))
 
 #ifndef TRUE
 #define TRUE 1
diff --git a/tools/test/perform/zip_perf.c b/tools/test/perform/zip_perf.c
index 6a1e1aa..517866b 100644
--- a/tools/test/perform/zip_perf.c
+++ b/tools/test/perform/zip_perf.c
@@ -32,11 +32,10 @@
 #define ONE_MB (ONE_KB * ONE_KB)
 #define ONE_GB (ONE_MB * ONE_KB)
 
-#define MICROSECOND 1000000.0F
+#define MICROSECOND 1000000.0
 
 /* report 0.0 in case t is zero too */
-#define MB_PER_SEC(bytes, t)                                                                                 \
-    ((fabs(t) < (double)0.0000000001F) ? (double)0.0F : ((((double)bytes) / (double)ONE_MB) / (t)))
+#define MB_PER_SEC(bytes, t) ((fabs(t) < 0.0000000001) ? 0.0 : ((((double)bytes) / (double)ONE_MB) / (t)))
 
 #ifndef TRUE
 #define TRUE 1
@@ -169,7 +168,7 @@ write_file(Bytef *source, uLongf sourceLen)
 
     /* destination buffer needs to be at least 0.1% larger than sourceLen
      * plus 12 bytes */
-    destLen = (uLongf)((double)sourceLen + ((double)sourceLen * (double)0.1F)) + 12;
+    destLen = (uLongf)((double)sourceLen + ((double)sourceLen * 0.1)) + 12;
     dest    = (Bytef *)HDmalloc(destLen);
 
     if (!dest)
@@ -179,8 +178,8 @@ write_file(Bytef *source, uLongf sourceLen)
     compress_buffer(dest, &destLen, source, sourceLen);
     HDgettimeofday(&timer_stop, NULL);
 
-    compression_time += ((double)timer_stop.tv_sec + ((double)timer_stop.tv_usec) / (double)MICROSECOND) -
-                        ((double)timer_start.tv_sec + ((double)timer_start.tv_usec) / (double)MICROSECOND);
+    compression_time += ((double)timer_stop.tv_sec + ((double)timer_stop.tv_usec) / MICROSECOND) -
+                        ((double)timer_start.tv_sec + ((double)timer_start.tv_usec) / MICROSECOND);
 
     if (report_once_flag) {
         HDfprintf(stdout, "\tCompression Ratio: %g\n", ((double)destLen) / (double)sourceLen);