Changes in Version 1.10

• Fixed some bugs.
• Implemented the BPX Preconditioned Conjugate Gradient method. Renamed the module MGSOLV and the program mgtest in MLSOLV and mlstest, respectively, because of their true multilevel character.
• Improved the estimation of extremal eigenvalues by the Lanczos method.
• Accelerated the iterative solvers for zero initial solution (which arises often within the multigrid algorithm).
• Changed the defaults for accuracy in modules RTC and EIGENVAL to 1e-8 and 1e-4, respectively.
• Extended the structure of type QMatrix, e.g. by reciprocal values of diagonal elements which are needed in classical solvers (Jacobi, SOR method) are stored as auxiliary variables.
• Implemented the procedure V_SetRndCmp in module VECTOR which initializes vector components by random values.
• Modified the stopping criterion for GMRES.
• Changed the names of some procedures and variables.