#include "MathFunctions.h" #include // include the generated table #include "Table.h" #include namespace mathfunctions { namespace detail { // a hack square root calculation using simple operations double mysqrt(double x) { if (x <= 0) { 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) { result = sqrtTable[static_cast(x)]; } // if we have both log and exp then use them // do ten iterations for (int i = 0; i < 10; ++i) { if (result <= 0) { result = 0.1; } double delta = x - (result * result); result = result + 0.5 * delta / result; std::cout << "Computing sqrt of " << x << " to be " << result << std::endl; } #endif return result; } } }