src/gmxlib/invsqrt_test.c

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  35 /* This file is completely threadsafe - keep it that way! */
  36
  37 #include "vec.h"
  38
  39 int main(int argc,char *argv[])
  40 {
  41   real x,y,z,diff,av;
  42   int  i;
  43
  44   printf("%12s  %12s  %12s  %12s  %12s\n","X","invsqrt(X)","1/sqrt(X)","Abs. Diff.","Rel. Diff.");
  45   for(i=1; (i<1000); i++) {
  46     x = i*1.0;
  47     y = gmx_invsqrt(x);
  48     z = 1.0/sqrt(x);
  49     diff = y-z;
  50     av   = 0.5*(y+z);
  51     printf("%12.5e  %12.5e  %12.5e  %12.5e  %12.5e\n",x,y,z,diff,diff/z);
  52   }
  53   return 0;
  54 }