mathutils.cpp

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#include <cfloat>
#include <cmath>
#include <climits>
using namespace std;
#include "mathutils.h"

double deg2rad(double deg)
// post: return radian equivalent of deg degrees
{
    return deg*PI/180;
}

double rad2deg(double rad)
// post: return degree equivalent of rad radians
{
    return rad*180/PI;
}

bool FloatEqual(double lhs, double rhs)
// postcondition: returns true if lhs == rhs where equality
//                is determined by using relative error, i.e.
//                |lhs-rhs| / min(|lhs|,|rhs|)     
{
    const double EPSILON = DBL_EPSILON*10;  // precision for equality

    double flhs = fabs(lhs);          // compute absolute values
    double frhs = fabs(rhs);
    double min = frhs;
    if (flhs < frhs)                  // set minimum of absolute values
    {
        min = flhs;
    }
    if (min < EPSILON)                // avoid division by zero, check
    {
        return (fabs(lhs-rhs) < EPSILON);
    }
    return (fabs(lhs-rhs)/min < EPSILON);
}