QR 分解 （包括Householer, Givens, 经典Gram Schmidt, 修正的GS methods)-QR factorization including Householer, Givens, CGS, MGS

In numerical linear algebra, the biconjugate gradient stabilized method, often abbreviated as BiCGSTAB, is an iterative method developed by H. A. van der Vorst for the numerical solution of nonsymmetric linear systems. It is a variant of the biconjug