Merge topic 'cmake-tutorial'

6f6a32a0f6 Tutorial: Improve Step 9
6a35d630dc Tutorial: Improve Step 8
61d4d990d6 Tutorial: Improve Step 7
a36731c634 Tutorial: Improve Step 6
df9cdf629c Tutorial: Improve Step 5
442c0f0d46 Tutorial: Improve Step 4
bc64401c3d Tutorial: Improve Step 3
49ce4d6ff4 Tutorial: Improve Step 2
...

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !3528

2 files changed, 4 insertions, 23 deletions

diff --git a/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt b/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt
index c12955d..dfa84c9 100644
--- a/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt
+++ b/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt
@@ -13,11 +13,7 @@ target_include_directories(MathFunctions
 option(USE_MYMATH "Use tutorial provided math implementation" ON)
 if(USE_MYMATH)
 
-  # does this system provide the log and exp functions?
-  include(CheckSymbolExists)
-  set(CMAKE_REQUIRED_LIBRARIES "m")
-  check_symbol_exists(log "math.h" HAVE_LOG)
-  check_symbol_exists(exp "math.h" HAVE_EXP)
+  target_compile_definitions(MathFunctions PRIVATE "USE_MYMATH")
 
   # first we add the executable that generates the table
   add_executable(MakeTable MakeTable.cxx)
@@ -41,18 +37,12 @@ if(USE_MYMATH)
                              ${CMAKE_CURRENT_BINARY_DIR}
                              )
 
+  # state that SqrtLibrary need PIC when the default is shared libraries
   set_target_properties(SqrtLibrary PROPERTIES
                         POSITION_INDEPENDENT_CODE ${BUILD_SHARED_LIBS}
                         )
 
   target_link_libraries(SqrtLibrary PUBLIC tutorial_compiler_flags)
-
-
-  target_compile_definitions(MathFunctions PRIVATE "USE_MYMATH")
-  if(HAVE_LOG AND HAVE_EXP)
-    target_compile_definitions(SqrtLibrary
-                               PRIVATE "HAVE_LOG" "HAVE_EXP")
-  endif()
   target_link_libraries(MathFunctions PRIVATE SqrtLibrary)
 endif()
 
diff --git a/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx
index 96d9421..ff37312 100644
--- a/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx
+++ b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx
@@ -4,8 +4,6 @@
 // include the generated table
 #include "Table.h"
 
-#include <cmath>
-
 namespace mathfunctions {
 namespace detail {
 // a hack square root calculation using simple operations
@@ -15,20 +13,13 @@ double mysqrt(double x)
     return 0;
   }
 
-  // if we have both log and exp then use them
-#if defined(HAVE_LOG) && defined(HAVE_EXP)
-  double result = exp(log(x) * 0.5);
-  std::cout << "Computing sqrt of " << x << " to be " << result << " using log"
-            << std::endl;
-#else
   // use the table to help find an initial value
   double result = x;
   if (x >= 1 && x < 10) {
+    std::cout << "Use the table to help find an initial value " << std::endl;
     result = sqrtTable[static_cast<int>(x)];
   }
 
-  // if we have both log and exp then use them
-
   // do ten iterations
   for (int i = 0; i < 10; ++i) {
     if (result <= 0) {
@@ -38,7 +29,7 @@ double mysqrt(double x)
     result = result + 0.5 * delta / result;
     std::cout << "Computing sqrt of " << x << " to be " << result << std::endl;
   }
-#endif
+
   return result;
 }
 }