diff --git a/CMakeLists.txt b/CMakeLists.txt
index 051cf633241da86ec46313444b913d3cec45feac..46b4d5eb07dc7557e5be7f0f451ccd426ca79d19 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -44,7 +44,7 @@ option(ENABLE_NETGEN "Enable Netgen mesh generator" ON)
 option(ENABLE_OCC "Enable Open CASCADE geometrical models" ON)
 option(ENABLE_OSMESA "Use OSMesa for offscreen rendering" OFF)
 option(ENABLE_PARSER "Build the GEO file parser" ON)
-option(ENABLE_PETSC "Enable PETSc linear algebra solvers" OFF)
+option(ENABLE_PETSC "Enable PETSc linear algebra solvers" ON)
 option(ENABLE_PLUGINS "Build the post-processing plugins" ON)
 option(ENABLE_POST "Build the post-processing module" ON)
 option(ENABLE_QT "Build QT GUI" OFF)
@@ -463,13 +463,17 @@ if(ENABLE_GMM)
 endif(ENABLE_GMM)
 
 if(ENABLE_KBIPACK)
-  add_subdirectory(contrib/kbipack)
-  include_directories(contrib/kbipack)
-  set_config_option(HAVE_KBIPACK "Kbipack")
   find_library(GMP_LIB NAMES gmp)
   if(GMP_LIB)
-    set_config_option(HAVE_GMP "GMP")
-    list(APPEND EXTERNAL_LIBRARIES ${GMP_LIB})
+    find_path(GMP_INC "gmp.h" PATH_SUFFIXES src include)
+    if(GMP_INC)
+      set_config_option(HAVE_GMP "GMP")
+      list(APPEND EXTERNAL_LIBRARIES ${GMP_LIB})
+      list(APPEND EXTERNAL_INCLUDES ${GMP_INC})
+      add_subdirectory(contrib/kbipack)
+      include_directories(contrib/kbipack)
+      set_config_option(HAVE_KBIPACK "Kbipack")
+    endif(GMP_INC)
   endif(GMP_LIB)
 endif(ENABLE_KBIPACK)
 
@@ -479,17 +483,6 @@ if(ENABLE_MATHEX)
   set_config_option(HAVE_MATHEX "MathEx")
 endif(ENABLE_MATHEX)
 
-if(ENABLE_MPI)
-   find_package(MPI)
-   if(MPI_FOUND)
-     set_config_option(HAVE_MPI "MPI")
-     list(APPEND EXTERNAL_INCLUDES ${MPI_INCLUDE_DIR})
-     list(APPEND EXTERNAL_LIBRARIES ${MPI_LIBRARIES})
-     include(CMakeForceCompiler)
-     cmake_force_cxx_compiler(${MPI_COMPILER} "MPI C++ Compiler")
-   endif(MPI_FOUND)
-endif(ENABLE_MPI)
-
 if(ENABLE_MPEG_ENCODE)
   add_subdirectory(contrib/mpeg_encode)
   include_directories(contrib/mpeg_encode/headers)
@@ -612,6 +605,7 @@ if(ENABLE_PETSC)
   set(ENV_PETSC_ARCH $ENV{PETSC_ARCH})
   if(EXISTS ${ENV_PETSC_DIR}/${ENV_PETSC_ARCH}/conf/petscvariables)
     set_config_option(HAVE_PETSC "PETSc")
+    set_config_option(HAVE_MPI "MPI")
     file(STRINGS ${ENV_PETSC_DIR}/${ENV_PETSC_ARCH}/conf/petscvariables 
          PETSC_VARIABLES NEWLINE_CONSUME)
     # find include directories
@@ -621,26 +615,31 @@ if(ENABLE_PETSC)
            ${PETSC_VARIABLES})
     string(REPLACE "PACKAGES_INCLUDES = " "" PETSC_PACKAGES_INCLUDES
            ${PETSC_PACKAGES_INCLUDES})
-    if (PETSC_PACKAGES_INCLUDES)
+    if(PETSC_PACKAGES_INCLUDES)
       string(REPLACE "-I" "" PETSC_PACKAGES_INCLUDES ${PETSC_PACKAGES_INCLUDES})
       string(REPLACE " " ";" PETSC_PACKAGES_INCLUDES ${PETSC_PACKAGES_INCLUDES})
         foreach(VAR ${PETSC_PACKAGES_INCLUDES})
       list(APPEND EXTERNAL_INCLUDES ${VAR})
       endforeach(VAR)
-    endif (PETSC_PACKAGES_INCLUDES)
+    endif(PETSC_PACKAGES_INCLUDES)
     # find libraries (<= 3.0)
     set(PETSC_LIBS_REQUIRED petscksp petscdm petscmat petscvec petsc)
     find_all_libraries(PETSC_LIBS PETSC_LIBS_REQUIRED 
                        ${ENV_PETSC_DIR}/${ENV_PETSC_ARCH}/lib "")
-    # petsc 3.1 create only one library (libpetsc)
-    if (NOT PETSC_LIBS)
-      find_library (PETSC_LIBS petsc PATHS ${ENV_PETSC_DIR}/${ENV_PETSC_ARCH}/lib)
+    # petsc 3.1 creates only one library (libpetsc)
+    if(NOT PETSC_LIBS)
+      find_library(PETSC_LIBS petsc PATHS ${ENV_PETSC_DIR}/${ENV_PETSC_ARCH}/lib)
     endif(NOT PETSC_LIBS)
-    string(REGEX MATCH "PACKAGES_LIBS = [^\n\r]*" PETSC_PACKAGES_LIBS
-           ${PETSC_VARIABLES})
-    string(REPLACE "PACKAGES_LIBS = " "" PETSC_PACKAGES_LIBS
-           ${PETSC_PACKAGES_LIBS})
-    list(APPEND EXTERNAL_LIBRARIES ${PETSC_LIBS} "${PETSC_PACKAGES_LIBS}")
+    list(APPEND EXTERNAL_LIBRARIES ${PETSC_LIBS})
+    # find additional libraries to link with
+    string(REGEX MATCH "PACKAGES_LIBS = [^\n\r]*" PLIBS ${PETSC_VARIABLES})
+    string(REPLACE "PACKAGES_LIBS = " "" PLIBS ${PLIBS})
+    string(STRIP ${PLIBS} PLIBS)
+    list(APPEND EXTERNAL_LIBRARIES "${PLIBS}")
+    string(REGEX MATCH "PCC_LINKER_LIBS = [^\n\r]*" LLIBS ${PETSC_VARIABLES})
+    string(REPLACE "PCC_LINKER_LIBS = " "" LLIBS ${LLIBS})
+    string(STRIP ${LLIBS} LLIBS)
+    list(APPEND EXTERNAL_LIBRARIES "${LLIBS}")
   endif(EXISTS ${ENV_PETSC_DIR}/${ENV_PETSC_ARCH}/conf/petscvariables)
 endif(ENABLE_PETSC)
 
@@ -654,6 +653,18 @@ if(HAVE_PETSC AND ENABLE_SLEPC)
   endif(SLEPC_LIB)
 endif(HAVE_PETSC AND ENABLE_SLEPC)
 
+if(ENABLE_MPI AND NOT HAVE_PETSC)
+  # if we use PETSc we assume that we use petsc's mpi config
+  find_package(MPI)
+  if(MPI_FOUND)
+    set_config_option(HAVE_MPI "MPI")
+    list(APPEND EXTERNAL_INCLUDES ${MPI_INCLUDE_DIR})
+    list(APPEND EXTERNAL_LIBRARIES ${MPI_LIBRARIES})
+    include(CMakeForceCompiler)
+    cmake_force_cxx_compiler(${MPI_COMPILER} "MPI C++ Compiler")
+  endif(MPI_FOUND)
+endif(ENABLE_MPI AND NOT HAVE_PETSC)
+
 if(ENABLE_OCC)
   if(WIN32)
     set(OCC_SYS_NAME win32)
@@ -684,8 +695,6 @@ if(ENABLE_OCC)
     # unset(OCC_LIB CACHE) # cleaner, but only available in cmake >= 2.6.4
   endforeach(OCC)
   list(LENGTH OCC_LIBS NUM_OCC_LIBS)
-
-
   if(NUM_OCC_LIBS EQUAL NUM_OCC_LIBS_REQUIRED)
     find_path(OCC_INC "BRep_Tool.hxx" PATHS ENV CASROOT PATH_SUFFIXES inc 
               include opencascade)