diff --git a/include/GooseFEM/MatrixPartitioned.hpp b/include/GooseFEM/MatrixPartitioned.hpp
index d21471a..7e36a79 100644
--- a/include/GooseFEM/MatrixPartitioned.hpp
+++ b/include/GooseFEM/MatrixPartitioned.hpp
@@ -1,506 +1,516 @@
 /**
 Implementation of MatrixPartitioned.h
 
 \file MatrixPartitioned.hpp
 \copyright Copyright 2017. Tom de Geus. All rights reserved.
 \license This project is released under the GNU Public License (GPLv3).
 */
 
 #ifndef GOOSEFEM_MATRIXPARTITIONED_HPP
 #define GOOSEFEM_MATRIXPARTITIONED_HPP
 
 #include "MatrixPartitioned.h"
 #include "Mesh.h"
 
 namespace GooseFEM {
 
 inline MatrixPartitioned::MatrixPartitioned(
     const xt::xtensor<size_t, 2>& conn,
     const xt::xtensor<size_t, 2>& dofs,
     const xt::xtensor<size_t, 1>& iip)
 {
     m_conn = conn;
     m_dofs = dofs;
     m_iip = iip;
     m_nelem = m_conn.shape(0);
     m_nne = m_conn.shape(1);
     m_nnode = m_dofs.shape(0);
     m_ndim = m_dofs.shape(1);
     m_iiu = xt::setdiff1d(dofs, iip);
     m_ndof = xt::amax(m_dofs)() + 1;
     m_nnp = m_iip.size();
     m_nnu = m_iiu.size();
     m_part = Mesh::Reorder({m_iiu, m_iip}).apply(m_dofs);
     m_Tuu.reserve(m_nelem * m_nne * m_ndim * m_nne * m_ndim);
     m_Tup.reserve(m_nelem * m_nne * m_ndim * m_nne * m_ndim);
     m_Tpu.reserve(m_nelem * m_nne * m_ndim * m_nne * m_ndim);
     m_Tpp.reserve(m_nelem * m_nne * m_ndim * m_nne * m_ndim);
     m_Auu.resize(m_nnu, m_nnu);
     m_Aup.resize(m_nnu, m_nnp);
     m_Apu.resize(m_nnp, m_nnu);
     m_App.resize(m_nnp, m_nnp);
 
     GOOSEFEM_ASSERT(xt::amax(m_conn)() + 1 <= m_nnode);
     GOOSEFEM_ASSERT(xt::amax(m_iip)() <= xt::amax(m_dofs)());
     GOOSEFEM_ASSERT(m_ndof <= m_nnode * m_ndim);
 }
 
+inline size_t MatrixPartitioned::nnu() const
+{
+    return m_nnu;
+}
+
+inline size_t MatrixPartitioned::nnp() const
+{
+    return m_nnp;
+}
+
 inline xt::xtensor<size_t, 1> MatrixPartitioned::iiu() const
 {
     return m_iiu;
 }
 
 inline xt::xtensor<size_t, 1> MatrixPartitioned::iip() const
 {
     return m_iip;
 }
 
 inline void MatrixPartitioned::assemble(const xt::xtensor<double, 3>& elemmat)
 {
     GOOSEFEM_ASSERT(xt::has_shape(elemmat, {m_nelem, m_nne * m_ndim, m_nne * m_ndim}));
 
     m_Tuu.clear();
     m_Tup.clear();
     m_Tpu.clear();
     m_Tpp.clear();
 
     for (size_t e = 0; e < m_nelem; ++e) {
         for (size_t m = 0; m < m_nne; ++m) {
             for (size_t i = 0; i < m_ndim; ++i) {
 
                 size_t di = m_part(m_conn(e, m), i);
 
                 for (size_t n = 0; n < m_nne; ++n) {
                     for (size_t j = 0; j < m_ndim; ++j) {
 
                         size_t dj = m_part(m_conn(e, n), j);
 
                         if (di < m_nnu && dj < m_nnu) {
                             m_Tuu.push_back(Eigen::Triplet<double>(
                                 di, dj, elemmat(e, m * m_ndim + i, n * m_ndim + j)));
                         }
                         else if (di < m_nnu) {
                             m_Tup.push_back(Eigen::Triplet<double>(
                                 di, dj - m_nnu, elemmat(e, m * m_ndim + i, n * m_ndim + j)));
                         }
                         else if (dj < m_nnu) {
                             m_Tpu.push_back(Eigen::Triplet<double>(
                                 di - m_nnu, dj, elemmat(e, m * m_ndim + i, n * m_ndim + j)));
                         }
                         else {
                             m_Tpp.push_back(Eigen::Triplet<double>(
                                 di - m_nnu,
                                 dj - m_nnu,
                                 elemmat(e, m * m_ndim + i, n * m_ndim + j)));
                         }
                     }
                 }
             }
         }
     }
 
     m_Auu.setFromTriplets(m_Tuu.begin(), m_Tuu.end());
     m_Aup.setFromTriplets(m_Tup.begin(), m_Tup.end());
     m_Apu.setFromTriplets(m_Tpu.begin(), m_Tpu.end());
     m_App.setFromTriplets(m_Tpp.begin(), m_Tpp.end());
     m_changed = true;
 }
 
 inline void MatrixPartitioned::set(
     const xt::xtensor<size_t, 1>& rows,
     const xt::xtensor<size_t, 1>& cols,
     const xt::xtensor<double, 2>& matrix)
 {
     GOOSEFEM_ASSERT(rows.size() == matrix.shape(0));
     GOOSEFEM_ASSERT(cols.size() == matrix.shape(1));
     GOOSEFEM_ASSERT(xt::amax(cols)() < m_ndof);
     GOOSEFEM_ASSERT(xt::amax(rows)() < m_ndof);
 
     std::vector<Eigen::Triplet<double>> Tuu;
     std::vector<Eigen::Triplet<double>> Tup;
     std::vector<Eigen::Triplet<double>> Tpu;
     std::vector<Eigen::Triplet<double>> Tpp;
 
     for (size_t i = 0; i < rows.size(); ++i) {
         for (size_t j = 0; j < cols.size(); ++j) {
             size_t di = rows(i);
             size_t dj = cols(j);
             double v = matrix(i, j);
 
             if (di < m_nnu && dj < m_nnu) {
                 Tuu.push_back(Eigen::Triplet<double>(di, dj, v));
             }
             else if (di < m_nnu) {
                 Tup.push_back(Eigen::Triplet<double>(di, dj - m_nnu, v));
             }
             else if (dj < m_nnu) {
                 Tpu.push_back(Eigen::Triplet<double>(di - m_nnu, dj, v));
             }
             else {
                 Tpp.push_back(Eigen::Triplet<double>(di - m_nnu, dj - m_nnu, v));
             }
         }
     }
 
     m_Auu.setFromTriplets(Tuu.begin(), Tuu.end());
     m_Aup.setFromTriplets(Tup.begin(), Tup.end());
     m_Apu.setFromTriplets(Tpu.begin(), Tpu.end());
     m_App.setFromTriplets(Tpp.begin(), Tpp.end());
     m_changed = true;
 }
 
 inline void MatrixPartitioned::add(
     const xt::xtensor<size_t, 1>& rows,
     const xt::xtensor<size_t, 1>& cols,
     const xt::xtensor<double, 2>& matrix)
 {
     GOOSEFEM_ASSERT(rows.size() == matrix.shape(0));
     GOOSEFEM_ASSERT(cols.size() == matrix.shape(1));
     GOOSEFEM_ASSERT(xt::amax(cols)() < m_ndof);
     GOOSEFEM_ASSERT(xt::amax(rows)() < m_ndof);
 
     std::vector<Eigen::Triplet<double>> Tuu;
     std::vector<Eigen::Triplet<double>> Tup;
     std::vector<Eigen::Triplet<double>> Tpu;
     std::vector<Eigen::Triplet<double>> Tpp;
 
     Eigen::SparseMatrix<double> Auu(m_nnu, m_nnu);
     Eigen::SparseMatrix<double> Aup(m_nnu, m_nnp);
     Eigen::SparseMatrix<double> Apu(m_nnp, m_nnu);
     Eigen::SparseMatrix<double> App(m_nnp, m_nnp);
 
     for (size_t i = 0; i < rows.size(); ++i) {
         for (size_t j = 0; j < cols.size(); ++j) {
             size_t di = rows(i);
             size_t dj = cols(j);
             double v = matrix(i, j);
 
             if (di < m_nnu && dj < m_nnu) {
                 Tuu.push_back(Eigen::Triplet<double>(di, dj, v));
             }
             else if (di < m_nnu) {
                 Tup.push_back(Eigen::Triplet<double>(di, dj - m_nnu, v));
             }
             else if (dj < m_nnu) {
                 Tpu.push_back(Eigen::Triplet<double>(di - m_nnu, dj, v));
             }
             else {
                 Tpp.push_back(Eigen::Triplet<double>(di - m_nnu, dj - m_nnu, v));
             }
         }
     }
 
     Auu.setFromTriplets(Tuu.begin(), Tuu.end());
     Aup.setFromTriplets(Tup.begin(), Tup.end());
     Apu.setFromTriplets(Tpu.begin(), Tpu.end());
     App.setFromTriplets(Tpp.begin(), Tpp.end());
     m_Auu += Auu;
     m_Aup += Aup;
     m_Apu += Apu;
     m_App += App;
     m_changed = true;
 }
 
 inline void MatrixPartitioned::todense(xt::xtensor<double, 2>& ret) const
 {
     GOOSEFEM_ASSERT(xt::has_shape(ret, {m_ndof, m_ndof}));
 
     ret.fill(0.0);
 
     for (int k = 0; k < m_Auu.outerSize(); ++k) {
         for (Eigen::SparseMatrix<double>::InnerIterator it(m_Auu, k); it; ++it) {
             ret(it.row(), it.col()) = it.value();
         }
     }
 
     for (int k = 0; k < m_Aup.outerSize(); ++k) {
         for (Eigen::SparseMatrix<double>::InnerIterator it(m_Aup, k); it; ++it) {
             ret(it.row(), it.col() + m_nnu) = it.value();
         }
     }
 
     for (int k = 0; k < m_Apu.outerSize(); ++k) {
         for (Eigen::SparseMatrix<double>::InnerIterator it(m_Apu, k); it; ++it) {
             ret(it.row() + m_nnu, it.col()) = it.value();
         }
     }
 
     for (int k = 0; k < m_App.outerSize(); ++k) {
         for (Eigen::SparseMatrix<double>::InnerIterator it(m_App, k); it; ++it) {
             ret(it.row() + m_nnu, it.col() + m_nnu) = it.value();
         }
     }
 }
 
 inline void MatrixPartitioned::dot(const xt::xtensor<double, 2>& x, xt::xtensor<double, 2>& b) const
 {
     GOOSEFEM_ASSERT(xt::has_shape(b, {m_nnode, m_ndim}));
     GOOSEFEM_ASSERT(xt::has_shape(x, {m_nnode, m_ndim}));
 
     Eigen::VectorXd X_u = this->AsDofs_u(x);
     Eigen::VectorXd X_p = this->AsDofs_p(x);
     Eigen::VectorXd B_u = m_Auu * X_u + m_Aup * X_p;
     Eigen::VectorXd B_p = m_Apu * X_u + m_App * X_p;
 
     #pragma omp parallel for
     for (size_t m = 0; m < m_nnode; ++m) {
         for (size_t i = 0; i < m_ndim; ++i) {
             if (m_part(m, i) < m_nnu) {
                 b(m, i) = B_u(m_part(m, i));
             }
             else{
                 b(m, i) = B_p(m_part(m, i) - m_nnu);
             }
         }
     }
 }
 
 inline void MatrixPartitioned::dot(const xt::xtensor<double, 1>& x, xt::xtensor<double, 1>& b) const
 {
     GOOSEFEM_ASSERT(b.size() == m_ndof);
     GOOSEFEM_ASSERT(x.size() == m_ndof);
 
     Eigen::VectorXd X_u = this->AsDofs_u(x);
     Eigen::VectorXd X_p = this->AsDofs_p(x);
 
     Eigen::Map<Eigen::VectorXd>(b.data(), m_nnu).noalias() = m_Auu * X_u + m_Aup * X_p;
     Eigen::Map<Eigen::VectorXd>(b.data() + m_nnu, m_ndof).noalias() = m_Auu * X_u + m_Aup * X_p;
 }
 
 inline void
 MatrixPartitioned::reaction(const xt::xtensor<double, 2>& x, xt::xtensor<double, 2>& b) const
 {
     GOOSEFEM_ASSERT(xt::has_shape(x, {m_nnode, m_ndim}));
     GOOSEFEM_ASSERT(xt::has_shape(b, {m_nnode, m_ndim}));
 
     Eigen::VectorXd X_u = this->AsDofs_u(x);
     Eigen::VectorXd X_p = this->AsDofs_p(x);
     Eigen::VectorXd B_p = m_Apu * X_u + m_App * X_p;
 
     #pragma omp parallel for
     for (size_t m = 0; m < m_nnode; ++m) {
         for (size_t i = 0; i < m_ndim; ++i) {
             if (m_part(m, i) >= m_nnu) {
                 b(m, i) = B_p(m_part(m, i) - m_nnu);
             }
         }
     }
 }
 
 inline void
 MatrixPartitioned::reaction(const xt::xtensor<double, 1>& x, xt::xtensor<double, 1>& b) const
 {
     GOOSEFEM_ASSERT(x.size() == m_ndof);
     GOOSEFEM_ASSERT(b.size() == m_ndof);
 
     Eigen::VectorXd X_u = this->AsDofs_u(x);
     Eigen::VectorXd X_p = this->AsDofs_p(x);
     Eigen::VectorXd B_p = m_Apu * X_u + m_App * X_p;
 
     #pragma omp parallel for
     for (size_t d = 0; d < m_nnp; ++d) {
         b(m_iip(d)) = B_p(d);
     }
 }
 
 inline void MatrixPartitioned::reaction_p(
     const xt::xtensor<double, 1>& x_u,
     const xt::xtensor<double, 1>& x_p,
     xt::xtensor<double, 1>& b_p) const
 {
     GOOSEFEM_ASSERT(x_u.size() == m_nnu);
     GOOSEFEM_ASSERT(x_p.size() == m_nnp);
     GOOSEFEM_ASSERT(b_p.size() == m_nnp);
 
     Eigen::Map<Eigen::VectorXd>(b_p.data(), b_p.size()).noalias() =
         m_Apu * Eigen::Map<const Eigen::VectorXd>(x_u.data(), x_u.size()) +
         m_App * Eigen::Map<const Eigen::VectorXd>(x_p.data(), x_p.size());
 }
 
 inline xt::xtensor<double, 2>
 MatrixPartitioned::Reaction(const xt::xtensor<double, 2>& x, const xt::xtensor<double, 2>& b) const
 {
     xt::xtensor<double, 2> ret = b;
     this->reaction(x, ret);
     return ret;
 }
 
 inline xt::xtensor<double, 1>
 MatrixPartitioned::Reaction(const xt::xtensor<double, 1>& x, const xt::xtensor<double, 1>& b) const
 {
     xt::xtensor<double, 1> ret = b;
     this->reaction(x, ret);
     return ret;
 }
 
 inline xt::xtensor<double, 1> MatrixPartitioned::Reaction_p(
     const xt::xtensor<double, 1>& x_u, const xt::xtensor<double, 1>& x_p) const
 {
     xt::xtensor<double, 1> b_p = xt::empty<double>({m_nnp});
     this->reaction_p(x_u, x_p, b_p);
     return b_p;
 }
 
 inline Eigen::VectorXd MatrixPartitioned::AsDofs_u(const xt::xtensor<double, 1>& dofval) const
 {
     GOOSEFEM_ASSERT(dofval.size() == m_ndof);
 
     Eigen::VectorXd dofval_u(m_nnu, 1);
 
     #pragma omp parallel for
     for (size_t d = 0; d < m_nnu; ++d) {
         dofval_u(d) = dofval(m_iiu(d));
     }
 
     return dofval_u;
 }
 
 inline Eigen::VectorXd MatrixPartitioned::AsDofs_u(const xt::xtensor<double, 2>& nodevec) const
 {
     GOOSEFEM_ASSERT(xt::has_shape(nodevec, {m_nnode, m_ndim}));
 
     Eigen::VectorXd dofval_u = Eigen::VectorXd::Zero(m_nnu, 1);
 
     #pragma omp parallel for
     for (size_t m = 0; m < m_nnode; ++m) {
         for (size_t i = 0; i < m_ndim; ++i) {
             if (m_part(m, i) < m_nnu) {
                 dofval_u(m_part(m, i)) = nodevec(m, i);
             }
         }
     }
 
     return dofval_u;
 }
 
 inline Eigen::VectorXd MatrixPartitioned::AsDofs_p(const xt::xtensor<double, 1>& dofval) const
 {
     GOOSEFEM_ASSERT(dofval.size() == m_ndof);
 
     Eigen::VectorXd dofval_p(m_nnp, 1);
 
     #pragma omp parallel for
     for (size_t d = 0; d < m_nnp; ++d) {
         dofval_p(d) = dofval(m_iip(d));
     }
 
     return dofval_p;
 }
 
 inline Eigen::VectorXd MatrixPartitioned::AsDofs_p(const xt::xtensor<double, 2>& nodevec) const
 {
     GOOSEFEM_ASSERT(xt::has_shape(nodevec, {m_nnode, m_ndim}));
 
     Eigen::VectorXd dofval_p = Eigen::VectorXd::Zero(m_nnp, 1);
 
     #pragma omp parallel for
     for (size_t m = 0; m < m_nnode; ++m) {
         for (size_t i = 0; i < m_ndim; ++i) {
             if (m_part(m, i) >= m_nnu) {
                 dofval_p(m_part(m, i) - m_nnu) = nodevec(m, i);
             }
         }
     }
 
     return dofval_p;
 }
 
 template <class Solver>
 inline void MatrixPartitionedSolver<Solver>::factorize(MatrixPartitioned& matrix)
 {
     if (!matrix.m_changed && !m_factor) {
         return;
     }
     m_solver.compute(matrix.m_Auu);
     m_factor = false;
     matrix.m_changed = false;
 }
 
 template <class Solver>
 inline void MatrixPartitionedSolver<Solver>::solve(
     MatrixPartitioned& matrix, const xt::xtensor<double, 2>& b, xt::xtensor<double, 2>& x)
 {
     GOOSEFEM_ASSERT(xt::has_shape(b, {matrix.m_nnode, matrix.m_ndim}));
     GOOSEFEM_ASSERT(xt::has_shape(x, {matrix.m_nnode, matrix.m_ndim}));
 
     this->factorize(matrix);
     Eigen::VectorXd B_u = matrix.AsDofs_u(b);
     Eigen::VectorXd X_p = matrix.AsDofs_p(x);
     Eigen::VectorXd X_u = m_solver.solve(Eigen::VectorXd(B_u - matrix.m_Aup * X_p));
 
     #pragma omp parallel for
     for (size_t m = 0; m < matrix.m_nnode; ++m) {
         for (size_t i = 0; i < matrix.m_ndim; ++i) {
             if (matrix.m_part(m, i) < matrix.m_nnu) {
                 x(m, i) = X_u(matrix.m_part(m, i));
             }
         }
     }
 }
 
 template <class Solver>
 inline void MatrixPartitionedSolver<Solver>::solve(
     MatrixPartitioned& matrix, const xt::xtensor<double, 1>& b, xt::xtensor<double, 1>& x)
 {
     GOOSEFEM_ASSERT(b.size() == matrix.m_ndof);
     GOOSEFEM_ASSERT(x.size() == matrix.m_ndof);
 
     this->factorize(matrix);
     Eigen::VectorXd B_u = matrix.AsDofs_u(b);
     Eigen::VectorXd X_p = matrix.AsDofs_p(x);
     Eigen::VectorXd X_u = m_solver.solve(Eigen::VectorXd(B_u - matrix.m_Aup * X_p));
 
     #pragma omp parallel for
     for (size_t d = 0; d < matrix.m_nnu; ++d) {
         x(matrix.m_iiu(d)) = X_u(d);
     }
 }
 
 template <class Solver>
 inline void MatrixPartitionedSolver<Solver>::solve_u(
     MatrixPartitioned& matrix,
     const xt::xtensor<double, 1>& b_u,
     const xt::xtensor<double, 1>& x_p,
     xt::xtensor<double, 1>& x_u)
 {
     GOOSEFEM_ASSERT(b_u.size() == matrix.m_nnu);
     GOOSEFEM_ASSERT(x_p.size() == matrix.m_nnp);
     GOOSEFEM_ASSERT(x_u.size() == matrix.m_nnu);
 
     this->factorize(matrix);
 
     Eigen::Map<Eigen::VectorXd>(x_u.data(), x_u.size()).noalias() = m_solver.solve(Eigen::VectorXd(
         Eigen::Map<const Eigen::VectorXd>(b_u.data(), b_u.size()) -
         matrix.m_Aup * Eigen::Map<const Eigen::VectorXd>(x_p.data(), x_p.size())));
 }
 
 template <class Solver>
 inline xt::xtensor<double, 2> MatrixPartitionedSolver<Solver>::Solve(
     MatrixPartitioned& matrix, const xt::xtensor<double, 2>& b, const xt::xtensor<double, 2>& x)
 {
     xt::xtensor<double, 2> ret = x;
     this->solve(matrix, b, ret);
     return ret;
 }
 
 template <class Solver>
 inline xt::xtensor<double, 1> MatrixPartitionedSolver<Solver>::Solve(
     MatrixPartitioned& matrix, const xt::xtensor<double, 1>& b, const xt::xtensor<double, 1>& x)
 {
     xt::xtensor<double, 1> ret = x;
     this->solve(matrix, b, ret);
     return ret;
 }
 
 template <class Solver>
 inline xt::xtensor<double, 1> MatrixPartitionedSolver<Solver>::Solve_u(
     MatrixPartitioned& matrix, const xt::xtensor<double, 1>& b_u, const xt::xtensor<double, 1>& x_p)
 {
     xt::xtensor<double, 1> x_u = xt::empty<double>({matrix.m_nnu});
     this->solve_u(matrix, b_u, x_p, x_u);
     return x_u;
 }
 
 } // namespace GooseFEM
 
 #endif