From 72ecab76702b12e42b1306f8bb0cbcf300db5213 Mon Sep 17 00:00:00 2001
From: Martin Kronbichler <martin.kronbichler@it.uu.se>
Date: Wed, 23 Feb 2022 17:03:37 +0100
Subject: [PATCH] Fix run time error in step-75.

---
 examples/step-75/step-75.cc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/examples/step-75/step-75.cc b/examples/step-75/step-75.cc
index 744e5ab710..5487456221 100644
--- a/examples/step-75/step-75.cc
+++ b/examples/step-75/step-75.cc
@@ -427,6 +427,7 @@ namespace Step75
   void LaplaceOperator<dim, number>::compute_inverse_diagonal(
     VectorType &diagonal) const
   {
+    this->matrix_free.initialize_dof_vector(diagonal);
     MatrixFreeTools::compute_diagonal(matrix_free,
                                       diagonal,
                                       &LaplaceOperator::do_cell_integral_local,
-- 
2.39.5