Indefinite Ruhe’s Variant of the Block Lanczos Method for Solving the Systems of Linear Equations

Algorithm 6.

(1) Choose vectors such that the indefinite Gram-Schmidt orthogonalization gives result:

(2) For Do:

(3)  Compute

(4)   For … Do

(5)   

(6)   

(7)   EndDo

(8)  Compute the indefinite QR-factorization of

(9) EndDo