LibreCAD math

LibreCAD math

std::vector<double> RS_Math::quadraticSolver(const std::vector<double>& ce)
//quadratic solver for
// x^2 + ce[0] x + ce[1] =0
{
    std::vector<double> ans(0,0.);
    if(ce.size() != 2) return ans;
    double discriminant=0.25*ce[0]*ce[0]-ce[1];
	/* the discriminant may be very small and negative */
	if ( qAbs(discriminant) < 0.0000000001 ){
		ans.push_back(-0.5*ce[0] );
        ans.push_back(-ce[0] - ans[0]);
    }
	else if (discriminant >= 0.){
		ans.push_back(-0.5*ce[0] + sqrt(discriminant));
		ans.push_back(-ce[0] - ans[0]);
	}
	return ans;
}