Method solve

cpp/dolfinx/la/petsc.cpp:690–766

-----------------------------------------------------------------------------

}
//-----------------------------------------------------------------------------
int petsc::KrylovSolver::solve(Vec x, const Vec b, bool transpose) const
{
  common::Timer timer("PETSc Krylov solver");
  assert(x);
  assert(b);

  // Get PETSc operators
  Mat _A, _P;
  KSPGetOperators(_ksp, &_A, &_P);
  assert(_A);

  PetscErrorCode ierr;

  // Solve linear system
  spdlog::info("PETSc Krylov solver starting to solve system.");

  // Solve system
  if (!transpose)
  {
    ierr = KSPSolve(_ksp, b, x);
    if (ierr != 0)
      petsc::error(ierr, __FILE__, "KSPSolve");
  }
  else
  {
    ierr = KSPSolveTranspose(_ksp, b, x);
    if (ierr != 0)
      petsc::error(ierr, __FILE__, "KSPSolve");
  }

  // Get the number of iterations
  PetscInt num_iterations = 0;
  ierr = KSPGetIterationNumber(_ksp, &num_iterations);
  if (ierr != 0)
    petsc::error(ierr, __FILE__, "KSPGetIterationNumber");

  // Check if the solution converged and print error/warning if not
  // converged
  KSPConvergedReason reason;
  ierr = KSPGetConvergedReason(_ksp, &reason);
  if (ierr != 0)
    petsc::error(ierr, __FILE__, "KSPGetConvergedReason");
  if (reason < 0)
  {
    /*
    // Get solver residual norm
    double rnorm = 0;
    ierr = KSPGetResidualNorm(_ksp, &rnorm);
    if (ierr != 0) error(ierr, __FILE__, "KSPGetResidualNorm");
    const char *reason_str = KSPConvergedReasons[reason];
    bool error_on_nonconvergence =
    this->parameters["error_on_nonconvergence"].is_set() ?
    this->parameters["error_on_nonconvergence"] : true;
    if (error_on_nonconvergence)
    {
      log::dolfin_error("PETScKrylovSolver.cpp",
                   "solve linear system using PETSc Krylov solver",
                   "Solution failed to converge in %i iterations (PETSc reason