[WIP] Feature/solverfactory

This MR mainly contains the factory implementation from !5 (closed) with some cleanup:

• Allow creating solvers / preconditioners from ParameterTrees.

• A solver (including preconditioner) can now be configured via an ini file like this:

[solver]
precond = SeqSSOR
solver = CGSolver

[SeqSSOR]
iterations = 1
relaxation = 1.8

[CGSolver]
reduction=1e-9
maxit = 5000
verbose = 3

• The corresponding dune code currently looks like this:

auto solver = SolverPrecondFactory::create<VectorType> (matrix, configuration, "solver");

• Both the actual type of the solver/preconditioner and their parameters can chosen in the ini file.
• It is also possible to create only a solver or only a preconditioner this way. See the factory doxygen for details.

This MR depends on !84 (merged).

Note: change target branch to master, once !84 (merged) is merged!

cmake/modules/DuneIstlMacros.cmake

@@ -2,6 +2,25 @@
 #
 #    This modules content is executed whenever a module required or suggests dune-istl!
 #
+# .. cmake_function:: dune_add_istl_library
+#
+#    .. cmake_brief::
+#
+#       Adds a library with precompiled preconditioners and solvers
+#
+#    .. cmake_param:: BLOCKSIZES
+#       :multi:
+#
+#       The block sizes of vectors/matrices used in your module
+#
+#
+#    This function adds a library to the user's dune module which contains precompiled
+#    preconditioners and solvers. This allows for faster compilation of the actual module.
+#    This pays off especially when using a factory to create preconditioners and solvers
+#    dynamically.
+#    The vector/matrix block sizes used in your module must be passed in order for the
+#    precompiled preconditioners and solvers to be used.
+
 
 find_package(METIS)
 find_package(ParMETIS)
@@ -16,3 +35,87 @@ include(AddSuiteSparseFlags)
 # enable / disable backwards compatibility w.r.t. category
 set(DUNE_ISTL_SUPPORT_OLD_CATEGORY_INTERFACE 1
   CACHE BOOL "Enable/Disable the backwards compatibility of the category enum/method in dune-istl solvers, preconditioner, etc. '1'")
+
+# We always have to write the header because it will always be included
+file(WRITE ${CMAKE_BINARY_DIR}/solvertemplates.hh "// Placeholder for istl library includes\n")
+
+set (DUNE_ADD_ISTL_LIBRARY_CALLED 0 CACHE INTERNAL "")
+
+
+# Allow including a library for precompiled preconditioners / solvers
+function(dune_add_istl_library)
+
+  cmake_minimum_required(VERSION 3.1)
+
+  # Only allow this to be called once
+  if (DUNE_ADD_ISTL_LIBRARY_CALLED)
+    message(FATAL_ERROR "You may only call dune_add_istl_library once per module!")
+  endif()
+  set (DUNE_ADD_ISTL_LIBRARY_CALLED 1 CACHE INTERNAL "")
+
+  # Set library name from current module name
+  string(REGEX REPLACE "[^a-zA-Z0-9-]" "_" safe_proj_name ${CMAKE_PROJECT_NAME})
+  set(libname ${safe_proj_name}-istl)
+
+  # Check if listed in dune_enable_all_packages
+  set (found -1)
+  if (DUNE_ENABLE_ALL_PACKAGES_MODULE_LIBRARIES)
+    foreach(module_lib ${DUNE_ENABLE_ALL_PACKAGES_MODULE_LIBRARIES})
+      if (${module_lib} STREQUAL ${libname})
+        set (found 1)
+        break()
+      endif()
+    endforeach()
+  endif()
+  if (${found} EQUAL -1)
+    message(FATAL_ERROR "You have to register ${libname} as a module library in dune_enable_all_packages before calling dune_add_istl_library!")
+  endif()
+
+
+
+  # Parse input
+  include(CMakeParseArguments)
+  set(MULTIARGS BLOCKSIZES)
+  cmake_parse_arguments(ADDLIB "" "" "${MULTIARGS}" ${ARGN})
+
+  # Check whether the parser produced any errors
+  if(ADDLIB_UNPARSED_ARGUMENTS)
+    message(WARNING "Unrecognized arguments ('${ADDLIB_UNPARSED_ARGUMENTS}') for dune_add_istl_library!")
+  endif()
+
+  # Check BLOCKSIZES for correctness
+  if(NOT ADDLIB_BLOCKSIZES)
+    message(FATAL_ERROR "BLOCKSIZES has to be specified!")
+  endif()
+  foreach(bs ${ADDLIB_BLOCKSIZES})
+    if(NOT "${bs}" MATCHES "[1-9][0-9]*")
+      message(FATAL_ERROR "${bs} was given to the BLOCKSIZES arugment of dune_add_istl_library, but it does not seem like a correct block size number")
+    endif()
+  endforeach()
+
+
+
+  # Get module path of istl
+  dune_module_path(MODULE dune-istl RESULT moddir CMAKE_MODULES)
+
+  # Generate template instantiation headers and cc's
+  file(WRITE ${CMAKE_BINARY_DIR}/solvertemplates.cc "// Auto-generated template stuff\n")
+  file(WRITE ${CMAKE_BINARY_DIR}/solvertemplates.hh "// Auto-generated template stuff\n")
+  foreach(bs ${ADDLIB_BLOCKSIZES})
+    set(BLOCKSIZE ${bs})
+    configure_file("${moddir}/solvertemplates.hh" ${CMAKE_BINARY_DIR}/solvertemplates${bs}.hh)
+    configure_file("${moddir}/solvertemplates.cc" ${CMAKE_BINARY_DIR}/solvertemplates${bs}.cc)
+
+    file(APPEND ${CMAKE_BINARY_DIR}/solvertemplates.cc "#include \"solvertemplates${bs}.cc\"\n")
+    file(APPEND ${CMAKE_BINARY_DIR}/solvertemplates.hh "#include \"solvertemplates${bs}.hh\"\n")
+
+  endforeach()
+  include_directories(${CMAKE_BINARY_DIR})
+
+
+
+  # Build library
+  dune_library_add_sources(${libname} SOURCES ${CMAKE_BINARY_DIR}/solvertemplates.cc)
+
+
+endfunction()