From: Sebastian Proell <sebastian.proell@tum.de>
Date: Sat, 13 May 2023 09:56:17 +0000 (+0200)
Subject: Fix step-77: zero out residual before assembly
X-Git-Tag: v9.5.0-rc1~238^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F15210%2Fhead;p=dealii.git

Fix step-77: zero out residual before assembly
---

diff --git a/examples/step-77/step-77.cc b/examples/step-77/step-77.cc
index b58f350b20..ab75a26d72 100644
--- a/examples/step-77/step-77.cc
+++ b/examples/step-77/step-77.cc
@@ -334,6 +334,8 @@ namespace Step77
 
     std::cout << "  Computing residual vector..." << std::flush;
 
+    residual = 0.0;
+
     const QGauss<dim> quadrature_formula(fe.degree + 1);
     FEValues<dim>     fe_values(fe,
                             quadrature_formula,
diff --git a/tests/sundials/step-77.cc b/tests/sundials/step-77.cc
index 4c427d2636..d8aa4ffd28 100644
--- a/tests/sundials/step-77.cc
+++ b/tests/sundials/step-77.cc
@@ -243,6 +243,8 @@ namespace Step77
     const Vector<double> &evaluation_point,
     Vector<double> &      residual)
   {
+    residual = 0.0;
+
     const QGauss<dim> quadrature_formula(fe.degree + 1);
     FEValues<dim>     fe_values(fe,
                             quadrature_formula,