From bfa1d52e33e4a602ede1ff6ae933274d3ca221f7 Mon Sep 17 00:00:00 2001
From: Timo Heister <timo.heister@gmail.com>
Date: Sat, 3 Dec 2022 09:07:52 -0500
Subject: [PATCH] also fix test

---
 tests/sundials/step-77.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/sundials/step-77.cc b/tests/sundials/step-77.cc
index 32444acc3d..7585e58fb0 100644
--- a/tests/sundials/step-77.cc
+++ b/tests/sundials/step-77.cc
@@ -273,7 +273,7 @@ namespace Step77
                                     evaluation_point_gradients[q]);
 
             for (unsigned int i = 0; i < dofs_per_cell; ++i)
-              cell_residual(i) =
+              cell_residual(i) +=
                 (fe_values.shape_grad(i, q)      // \nabla \phi_i
                  * coeff                         // * a_n
                  * evaluation_point_gradients[q] // * \nabla u_n
-- 
2.39.5