Is it possible to call an external linear solver from Abaqus and/or Ansys?
This solver (which is supplied by me) would get the sparse matrix A and the right hand side vector b as inputs, and would return the solution x (with A x = b) to the program. Ideally, Abaqus/Ansys would also inform the solver about the desired algorithm (CG, BiCGstab, GMREs, ...) and preconditioner.