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authorBetsy McPhail <betsy.mcphail@kitware.com>2019-07-26 16:46:08 (GMT)
committerBrad King <brad.king@kitware.com>2019-08-19 15:49:05 (GMT)
commita36731c63460a41caae596b6dcbc75771a810549 (patch)
tree28c38e2c540d20eacbcf58cbadc5694c8cda82bf /Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx
parentdf9cdf629c5211282dcab2e4751f69032e25a244 (diff)
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Tutorial: Improve Step 6
* Print message when using the table * Remove duplicated comment * Remove HAVE_LOG and HAVE_EXP checks, use generated table instead
Diffstat (limited to 'Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx')
-rw-r--r--Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx13
1 files changed, 2 insertions, 11 deletions
diff --git a/Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx b/Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx
index 2b1d889..2ae60c6 100644
--- a/Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx
+++ b/Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx
@@ -4,8 +4,6 @@
// include the generated table
#include "Table.h"
-#include <cmath>
-
// a hack square root calculation using simple operations
double mysqrt(double x)
{
@@ -13,20 +11,13 @@ 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 and exp" << 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) {
@@ -36,6 +27,6 @@ double mysqrt(double x)
result = result + 0.5 * delta / result;
std::cout << "Computing sqrt of " << x << " to be " << result << std::endl;
}
-#endif
+
return result;
}