diff --git a/configure.ac b/configure.ac
index ab82a6594b7e599c78acea477f11b601d22fb7f2..48a891eff1ab4bd554ea5b1299fb2ff2e3c24c03 100644
--- a/configure.ac
+++ b/configure.ac
@@ -79,6 +79,8 @@ AC_CONFIG_FILES([dumux.pc
dumux/material/fluidsystems/Makefile
dumux/material/constraintsolvers/Makefile
dumux/material/eos/Makefile
+ dumux/multidomain/Makefile
+ dumux/multidomain/common/Makefile
dumux/nonlinear/Makefile
dumux/parallel/Makefile
m4/Makefile
diff --git a/dumux/Makefile.am b/dumux/Makefile.am
index bc835ce36fe34be06d1404ed62b5bbf2e60e0d39..640d0c72079152851d3f87e7662c01ed4ade1cc4 100644
--- a/dumux/Makefile.am
+++ b/dumux/Makefile.am
@@ -7,6 +7,7 @@ SUBDIRS = \
io \
linear \
material \
+ multidomain \
nonlinear \
parallel
diff --git a/dumux/multidomain/Makefile.am b/dumux/multidomain/Makefile.am
new file mode 100644
index 0000000000000000000000000000000000000000..f1de35a999ec8752a2b014375be2c176d35212e7
--- /dev/null
+++ b/dumux/multidomain/Makefile.am
@@ -0,0 +1,4 @@
+SUBDIRS = common
+multidomaindir = $(includedir)/dumux/multidomain
+
+include $(top_srcdir)/am/global-rules
diff --git a/dumux/multidomain/common/Makefile.am b/dumux/multidomain/common/Makefile.am
new file mode 100644
index 0000000000000000000000000000000000000000..1c56fe2ecadbe9cc1c8a185370bcdcfbb131c523
--- /dev/null
+++ b/dumux/multidomain/common/Makefile.am
@@ -0,0 +1,4 @@
+commondir = $(includedir)/dumux/multidomain/common
+common_HEADERS = *.hh
+
+include $(top_srcdir)/am/global-rules
diff --git a/dumux/multidomain/common/splitandmerge.hh b/dumux/multidomain/common/splitandmerge.hh
new file mode 100644
index 0000000000000000000000000000000000000000..80529da88be142cd4415109356ffc884e6af3886
--- /dev/null
+++ b/dumux/multidomain/common/splitandmerge.hh
@@ -0,0 +1,254 @@
+// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+// vi: set et ts=4 sw=4 sts=4:
+/*****************************************************************************
+ * See the file COPYING for full copying permissions. *
+ * *
+ * This program is free software: you can redistribute it and/or modify *
+ * it under the terms of the GNU General Public License as published by *
+ * the Free Software Foundation, either version 2 of the License, or *
+ * (at your option) any later version. *
+ * *
+ * This program is distributed in the hope that it will be useful, *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
+ * GNU General Public License for more details. *
+ * *
+ * You should have received a copy of the GNU General Public License *
+ * along with this program. If not, see <http://www.gnu.org/licenses/>. *
+ *****************************************************************************/
+/**
+ * \file
+ * \brief Some methods required by several classes of the coupling model.
+ */
+#ifndef DUMUX_SPLIT_AND_MERGE_HH
+#define DUMUX_SPLIT_AND_MERGE_HH
+
+#include "coupledproperties.hh"
+#include <dumux/common/valgrind.hh>
+
+namespace Dumux
+{
+/*!
+ * \addtogroup ModelCoupling
+ */
+// \{
+
+/*!
+ * \brief Some methods required by several classes of the coupling model.
+ */
+template<class TypeTag>
+class SplitAndMerge
+{
+ typedef typename GET_PROP_TYPE(TypeTag, SubProblem1TypeTag) SubTypeTag1;
+ typedef typename GET_PROP_TYPE(TypeTag, SubProblem2TypeTag) SubTypeTag2;
+
+ typedef typename GET_PROP_TYPE(TypeTag, SolutionVector) SolutionVector;
+ typedef typename GET_PROP_TYPE(SubTypeTag1, SolutionVector) SolutionVector1;
+ typedef typename GET_PROP_TYPE(SubTypeTag2, SolutionVector) SolutionVector2;
+
+ typedef typename GET_PROP_TYPE(TypeTag, JacobianMatrix) JacobianMatrix;
+ typedef typename GET_PROP_TYPE(SubTypeTag1, JacobianMatrix) JacobianMatrix1;
+ typedef typename GET_PROP_TYPE(SubTypeTag2, JacobianMatrix) JacobianMatrix2;
+
+ typedef typename GET_PROP_TYPE(TypeTag, Model) Model;
+ typedef typename GET_PROP_TYPE(SubTypeTag1, Model) Model1;
+ typedef typename GET_PROP_TYPE(SubTypeTag2, Model) Model2;
+
+ enum {
+ numEq1 = GET_PROP_VALUE(SubTypeTag1, NumEq),
+ numEq2 = GET_PROP_VALUE(SubTypeTag2, NumEq)
+ };
+public:
+ /*!
+ * \brief Merge two solution vectors of the sub models into a
+ * global vector: nonoverlapping case.
+ *
+ * \param vec1 docme
+ * \param vec2 docme
+ * \param dest docme
+ *
+ */
+ static void mergeSolVectors(const SolutionVector1 &vec1,
+ const SolutionVector2 &vec2,
+ SolutionVector &dest)
+ {
+// printvector(std::cout, vec1, "vec1", "row", 200, 1, 3);
+// printvector(std::cout, vec2, "vec2", "row", 200, 1, 3);
+
+ int nDofs1 = vec1.size();
+ int nDofs2 = vec2.size();
+
+ // merge the global vector into two individual ones
+ for (int i = 0; i < nDofs1; ++i)
+ for (int j = 0; j < numEq1; j++)
+ {
+ dest[i*numEq1 + j][0] = vec1[i][j];
+
+ Valgrind::CheckDefined(dest[i*numEq1 + j][0]);
+ }
+
+ for (int i = 0; i < nDofs2; ++i)
+ for (int j = 0; j < numEq2; j++)
+ {
+ dest[nDofs1*numEq1 + i*numEq2 + j][0] = vec2[i][j];
+
+ Valgrind::CheckDefined(dest[nDofs1*numEq1 + i*numEq2 + j][0]);
+ }
+
+// printvector(std::cout, dest, "dest", "row", 200, 1, 3);
+
+ }
+
+ /*!
+ * \brief Split a global solution vector into two solution vectors
+ * of the sub models: nonoverlapping case.
+ *
+ * \param vec docme
+ * \param dest1 docme
+ * \param dest2 docme
+ *
+ */
+ static void splitSolVector(const SolutionVector &vec,
+ SolutionVector1 &dest1,
+ SolutionVector2 &dest2)
+ {
+// printvector(std::cout, vec, "vec", "row", 200, 1, 3);
+
+ int nDofs1 = dest1.size();
+ int nDofs2 = dest2.size();
+
+ for (int i = 0; i < nDofs1; ++i)
+ for (int j = 0; j < numEq1; j++)
+ dest1[i][j] = vec[i*numEq1 + j][0];
+
+ for (int i = 0; i < nDofs2; ++i)
+ for (int j = 0; j < numEq2; j++)
+ dest2[i][j] = vec[nDofs1*numEq1 + i*numEq2 + j][0];
+
+// printvector(std::cout, dest1, "dest1", "row", 200, 1, 3);
+// printvector(std::cout, dest2, "dest2", "row", 200, 1, 3);
+
+ }
+
+ /*!
+ * \brief Merge two solution vectors of the sub models into a
+ * global vector: more general case.
+ *
+ * \param vec1 docme
+ * \param vec2 docme
+ * \param dest docme
+ * \param subDOFToCoupledDOF docme
+ *
+ */
+ static void mergeSolVectors(const SolutionVector1 &vec1,
+ const SolutionVector2 &vec2,
+ SolutionVector &dest,
+ const std::vector<int>& subDOFToCoupledDOF)
+ {
+ int nDofs1 = vec1.size();
+ int nDofs2 = vec2.size();
+// printvector(std::cout, vec1, "vec1", "row", 200, 1, 3);
+// printvector(std::cout, vec2, "vec2", "row", 200, 1, 3);
+
+ for (int i = 0; i < nDofs1; ++i)
+ for (int j = 0; j < numEq1; j++)
+ dest[i*numEq1 + j] = vec1[i][j];
+
+ for (int i = 0; i < nDofs2; ++i)
+ {
+ for (int j = numEq1; j < numEq2; j++)
+ dest[nDofs1*numEq1 + i*(numEq2-numEq1) + (j - numEq1)] = vec2[i][j];
+ }
+// printvector(std::cout, dest, "dest", "row", 200, 1, 3);
+ }
+
+ /*!
+ * \brief Split a global solution vector into two solution vectors
+ * of the sub models: more general case.
+ *
+ * \param vec docme
+ * \param dest1 docme
+ * \param dest2 docme
+ * \param subDOFToCoupledDOF docme
+ *
+ */
+ static void splitSolVector(const SolutionVector &vec,
+ SolutionVector1 &dest1,
+ SolutionVector2 &dest2,
+ const std::vector<int>& subDOFToCoupledDOF)
+ {
+ int nDofs1 = dest1.size();
+ int nDofs2 = dest2.size();
+
+// printvector(std::cout, vec, "vec", "row", 200, 1, 3);
+ for (int i = 0; i < nDofs1; ++i)
+ for (int j = 0; j < numEq1; j++)
+ dest1[i][j] = vec[i*numEq1 + j];
+
+ for (int i = 0; i < nDofs2; ++i)
+ {
+ int blockIdxCoupled = subDOFToCoupledDOF[i];
+ for (int j = 0; j < numEq1; j++)
+ {
+ dest2[i][j] = vec[blockIdxCoupled*numEq1 + j];
+ }
+
+ for (int j = numEq1; j < numEq2; j++)
+ dest2[i][j] = vec[nDofs1*numEq1 + i*(numEq2-numEq1) + (j - numEq1)];
+ }
+// printvector(std::cout, dest1, "dest1", "row", 200, 1, 3);
+// printvector(std::cout, dest2, "dest2", "row", 200, 1, 3);
+
+ }
+
+
+ /*!
+ * \brief Merge individual jacobian matrices of the sub models
+ * into a global jacobian matrix.
+ *
+ * \param M1 docme
+ * \param M2 docme
+ * \param M docme
+ *
+ */
+ static void mergeMatrices(const JacobianMatrix1 &M1,
+ const JacobianMatrix2 &M2,
+ JacobianMatrix &M)
+ {
+ DUNE_THROW(Dune::NotImplemented, "mergeMatrices in coupled common");
+ }
+
+ /*!
+ * \brief Copy a sub matrix into into the main diagonal of the global matrix.
+ *
+ * \param Msub docme
+ * \param M docme
+ * \param offset docme?
+ *
+ */
+ template <class SubMatrix>
+ static void copyMatrix(const SubMatrix &Msub,
+ JacobianMatrix &M,
+ size_t offset)
+ {
+ // loop over all rows of the submatrix
+ typedef typename SubMatrix::ConstRowIterator RowIterator;
+ typedef typename SubMatrix::ConstColIterator ColIterator;
+ RowIterator endRow = Msub.end();
+ for (RowIterator row = Msub.begin(); row != endRow; ++row) {
+ // loop over columns of the current row
+ ColIterator endCol = row->end();
+ for (ColIterator col = row->begin(); col != endCol; ++ col) {
+ // copy entry in the global matrix
+ M[row.index() + offset][col.index() + offset]
+ = *col;
+ }
+ }
+ }
+
+};
+// \}
+
+} // namespace Dumux
+
+#endif