csr_residuum Subroutine

public subroutine csr_residuum(a, x, b, res, resmax, epsb)

Computes the residuum ||Ax-b|| / (||b||+eps)

Arguments

Type IntentOptional Attributes Name
type(csrmat_t), intent(in) :: a

csr matrix

real(kind=FP), intent(in), dimension(a%ncol) :: x

Vector x

real(kind=FP), intent(in), dimension(a%ndim) :: b

Vector b

real(kind=FP), intent(out) :: res

Residuum (root mean square)

real(kind=FP), intent(out), optional :: resmax

Residuum (maximum)

real(kind=FP), intent(in), optional :: epsb

Tolerance for division of b in residual Dafault value FP_EPS