From f2ddeebe2144b31dcc38291ceaf281f1046b56e4 Mon Sep 17 00:00:00 2001
From: BalticPinguin <hu.bert@xemail.me>
Date: Fri, 30 Jun 2023 12:21:04 +0200
Subject: [PATCH] Set operators also for unrestricted solve & without
 preconditioner.

---
 src/solvers/petsc_linear_solver.C | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/solvers/petsc_linear_solver.C b/src/solvers/petsc_linear_solver.C
index 5d82ead5120..784d77c2691 100644
--- a/src/solvers/petsc_linear_solver.C
+++ b/src/solvers/petsc_linear_solver.C
@@ -632,6 +632,11 @@ PetscLinearSolver<T>::solve_base (SparseMatrix<T> * matrix,
           ierr = KSPSetOperators(_ksp, mat, const_cast<PetscMatrix<T> *>(precond)->mat());
           LIBMESH_CHKERR(ierr);
         }
+      else
+        {
+          ierr = KSPSetOperators(_ksp, mat, mat);
+          LIBMESH_CHKERR(ierr);
+        }
 
       if (this->_preconditioner)
         {