id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
13603,sinc_pi can be more precise with Horner's  method,minorlogic@…,John Maddock,"        double sinc1 = 1.0 + x2 * (-1.0 + x2 / 20.0) / 6.0;

        double sinc2 = 1.0 - x2 /6.0 + x2*x2 / 120.0;

in some cases sinc1 provides better precision compared to sinc2

    x generated with 

    double x = sqrt(sqrt(std::numeric_limits<double>::epsilon()));
    for (int i = 0; x > sqrt(std::numeric_limits<double>::epsilon()); i++)
    {
        x *= 0.99876765378657564;
    }
",Bugs,closed,To Be Determined,math,Boost 1.63.0,Optimization,fixed,sinc_pi  Horner,