From: Timo Heister <timo.heister@gmail.com>
Date: Tue, 10 Nov 2015 13:42:46 +0000 (-0500)
Subject: decide between Trilinos and PETSc in step-40
X-Git-Tag: v8.4.0-rc2~235^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F1856%2Fhead;p=dealii.git

decide between Trilinos and PETSc in step-40

based on a patch sent in by Kevin Drzycimski on the mailing list
---

diff --git a/examples/step-40/CMakeLists.txt b/examples/step-40/CMakeLists.txt
index 7130ef2874..d04cc77bac 100644
--- a/examples/step-40/CMakeLists.txt
+++ b/examples/step-40/CMakeLists.txt
@@ -37,12 +37,15 @@ ENDIF()
 #
 # Are all dependencies fulfilled?
 #
-IF(NOT DEAL_II_WITH_PETSC OR NOT DEAL_II_WITH_P4EST)
+IF(NOT (DEAL_II_WITH_PETSC OR DEAL_II_WITH_TRILINOS) OR NOT DEAL_II_WITH_P4EST)
   MESSAGE(FATAL_ERROR "
 Error! The deal.II library found at ${DEAL_II_PATH} was not configured with
     DEAL_II_WITH_PETSC = ON
     DEAL_II_WITH_P4EST = ON
-One or all of these are OFF in your installation but are required for this tutorial step."
+or
+    DEAL_II_WITH_TRILINOS = ON
+    DEAL_II_WITH_P4EST = ON
+One or both of these combinations are OFF in your installation but at least one is required for this tutorial step."
     )
 ENDIF()
 
diff --git a/examples/step-40/step-40.cc b/examples/step-40/step-40.cc
index d92c47423a..36f39ba0c2 100644
--- a/examples/step-40/step-40.cc
+++ b/examples/step-40/step-40.cc
@@ -30,14 +30,19 @@
 
 #include <deal.II/lac/generic_linear_algebra.h>
 
-#define USE_PETSC_LA
+// uncomment the following #define if you have PETSc and Trilinos installed
+// and you prefer using Trilinos in this example:
+// #define FORCE_USE_OF_TRILINOS
 
+// This will either import PETSc or TrilinosWrappers into the namespace LA:
 namespace LA
 {
-#ifdef USE_PETSC_LA
+#if defined(DEAL_II_WITH_PETSC) && !(defined(DEAL_II_WITH_TRILINOS) && defined(FORCE_USE_OF_TRILINOS))
   using namespace dealii::LinearAlgebraPETSc;
-#else
+#elif defined(DEAL_II_WITH_TRILINOS)
   using namespace dealii::LinearAlgebraTrilinos;
+#else
+#error DEAL_II_WITH_PETSC or DEAL_II_WITH_TRILINOS required
 #endif
 }