求解线性系统的Krylov方法的工具箱，包括经典的CG、GMRES等方法。-Solving Linear Systems Toolbox Krylov methods, including the classic CG, GMRES, etc..

SUBROUTINE TO FIND ALL REAL EIGENVALUES & EIGENVECTORS OF A REAL MATRIX [A]nxn 1. Characteristic Polynomial by the Leverrier Method 2. Eigenvalues (roots) of the Characteristic Polynomial by the Bairstow Method 3. Eigenvectors by t