43 lines
864 B
C++
43 lines
864 B
C++
#include <iostream>
|
|
|
|
#include "MathFunctions.h"
|
|
|
|
// include the generated table
|
|
#include "Table.h"
|
|
|
|
namespace mathfunctions
|
|
{
|
|
namespace detail
|
|
{
|
|
// a hack square root calculation using simple operations
|
|
double mysqrt(double x)
|
|
{
|
|
if (x <= 0)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
// 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)];
|
|
}
|
|
|
|
// 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;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
}
|
|
} |