public static float solveLeastSquares(Mat3 a, Vector3 b, Vector3 x, float svd_tol, int svd_sweeps, float pinv_tol)
{
Mat3 at;
SMat3 ata;
Vector3 atb;
MatUtils.transpose(out at, a);
MatUtils.mmul_ata(out ata, a);
MatUtils.vmul(out atb, at, b);
return(solveSymmetric(ata, atb, x, svd_tol, svd_sweeps, pinv_tol));
}