Add some documentation.

git-svn-id: https://svn.dealii.org/branches/branch_bigger_global_dof_indices_4@29717 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/cmake/setup_cached_variables.cmake b/deal.II/cmake/setup_cached_variables.cmake
index f368c3425dbdf2809f0b3eeb5bd6b3b8a234080b..4c3831b104262d2b23037e71c03359748c960ed3 100644 (file)
--- a/deal.II/cmake/setup_cached_variables.cmake
+++ b/deal.II/cmake/setup_cached_variables.cmake
@@ -237,11 +237,15 @@ FOREACH(_flag ${DEAL_II_USED_FLAGS})
   MARK_AS_ADVANCED(${_flag})
 ENDFOREACH()
 
+
+# 
+# Define the variable that defines whether we should use 32- or 64-bit
+# global DoF indices.
+#
 SET(DEAL_II_WITH_64BIT_INDICES "${DEAL_II_WITH_64BIT_INDICES}" CACHE BOOL
     "If set to ON, then use 64-bit data types to represent global degree of freedom indices. The default is to OFF. You only want to set this to ON if you will solve problems with more than 2^31 (approximately 2 billion) unknowns. If set to ON, you also need to ensure that both Trilinos and/or PETSc support 64-bit indices."
    )
 
-SET(DEAL_II_WITH_64BIT_INDICES_SAVED "${DEAL_II_WITH_64BIT_INDICES}")
 MARK_AS_ADVANCED(DEAL_II_WITH_64BIT_INDICES)