Examples: Require MPI for step-18

diff --git a/examples/step-18/CMakeLists.txt b/examples/step-18/CMakeLists.txt
index 24d76aa4a1243187d7c64191b1550bfbe0cb5ad3..8413167a4d66150a3f196de5b1875320ed893539 100644 (file)
--- a/examples/step-18/CMakeLists.txt
+++ b/examples/step-18/CMakeLists.txt
@@ -38,9 +38,10 @@ ENDIF ()
 #
 # Are all dependencies fulfilled?
 #
-IF(NOT DEAL_II_WITH_PETSC OR DEAL_II_PETSC_WITH_COMPLEX) # keep in one line
+IF(NOT DEAL_II_WITH_MPI OR NOT DEAL_II_WITH_PETSC OR DEAL_II_PETSC_WITH_COMPLEX) # keep in one line
   MESSAGE(FATAL_ERROR "
 Error! The deal.II library found at ${DEAL_II_PATH} was not configured with
+    DEAL_II_WITH_MPI = ON
     DEAL_II_WITH_PETSC = ON
     DEAL_II_PETSC_WITH_COMPLEX = OFF
 One or all of these are OFF in your installation but are required for this tutorial step."