int i, j;
float sum = 0;
int num = 100000000;
for( i = 0; i < num; ++i )
{
   for( j = 0; j < num; ++j )
   {
      float x = myDataX[i];
      float y = myDataY[j];
      float value = x+y;
      sum+=value;
   }
}