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authorDavid Cole <david.cole@kitware.com>2007-11-08 15:38:26 (GMT)
committerDavid Cole <david.cole@kitware.com>2007-11-08 15:38:26 (GMT)
commit4e752dee910d3901a438d97aedf49357a8cb5628 (patch)
tree3393d691a3e67c13610b9252e2f967d4433f95a6 /Tests/Tutorial/Step7/MathFunctions/mysqrt.cxx
parente615e1416cc5139082593c07db99ead11c6d5d46 (diff)
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ENH: Add new Tutorial steps. Diff between Step5 and Step6 shows how to add a cpack driven installer to your project. Diff between Step6 and Step7 shows how to add ctest dashboard scripting capability.
Diffstat (limited to 'Tests/Tutorial/Step7/MathFunctions/mysqrt.cxx')
-rw-r--r--Tests/Tutorial/Step7/MathFunctions/mysqrt.cxx44
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diff --git a/Tests/Tutorial/Step7/MathFunctions/mysqrt.cxx b/Tests/Tutorial/Step7/MathFunctions/mysqrt.cxx
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+#include <stdio.h>
+#include "MathFunctions.h"
+#include "TutorialConfig.h"
+
+// include the generated table
+#include "Table.h"
+
+#include <math.h>
+
+// a hack square root calculation using simple operations
+double mysqrt(double x)
+{
+ if (x <= 0)
+ {
+ return 0;
+ }
+
+ double result;
+
+ // if we have both log and exp then use them
+ double delta;
+
+ // use the table to help find an initial value
+ result = x;
+ if (x >= 1 && x < 10)
+ {
+ result = sqrtTable[static_cast<int>(x)];
+ }
+
+ // do ten iterations
+ int i;
+ for (i = 0; i < 10; ++i)
+ {
+ if (result <= 0)
+ {
+ result = 0.1;
+ }
+ delta = x - (result*result);
+ result = result + 0.5*delta/result;
+ fprintf(stdout,"Computing sqrt of %g to be %g\n",x,result);
+ }
+
+ return result;
+}