Function getError

test/testingutilities.cpp:23–36

See https://en.wikipedia.org/wiki/Relative_change_and_difference#Formulae

// See https://en.wikipedia.org/wiki/Relative_change_and_difference#Formulae
double getError(double exactVal, double approxVal)
{
    double maxAbsVal = std::max(std::abs(exactVal), std::abs(approxVal));

    // Both are ~0
    if(maxAbsVal < 1e-14)
    {
        return 0.0;
    }

    double absError = std::abs(exactVal - approxVal);

    return std::min(absError, absError / maxAbsVal);
}

// Checks if a is within margin of b
bool equalsWithinRange(double a, double b, double margin)