H-matrix (iterative method)

In mathematics, an "H"-matrix is a matrix whose comparison matrix is an M-matrix. It is useful in iterative methods.
Definition: Let be a complex matrix. Then comparison matrix "M"("A") of complex matrix "A" is defined as where for all and for all . If "M"("A") is a M-matrix, "A" is a "H"-matrix.
Invertible H-matrix guarantees convergence of Gauss–Seidel iterative methods.