Add utilities that will be needed for NLDD solvers.

Includes:
 - SubDomain struct,
 - simple partitioning utilities for testing,
 - some matrix and vector manipulation functions,
 - tests for the above.

tests/test10.partition

@@ -0,0 +1,10 @@
+0
+0
+1
+1
+2
+2
+1
+1
+0
+0

tests/test_extractMatrix.cpp

@@ -0,0 +1,112 @@
+/*
+  Copyright 2023 SINTEF Digital, Mathematics and Cybernetics.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM 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 3 of the License, or
+  (at your option) any later version.
+
+  OPM 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 OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <config.h>
+
+#define BOOST_TEST_MODULE OPM_test_extractMatrix
+#include <boost/test/unit_test.hpp>
+
+#include <opm/simulators/linalg/extractMatrix.hpp>
+#include <dune/common/fmatrix.hh>
+#include <dune/istl/bcrsmatrix.hh>
+#include <dune/istl/bvector.hh>
+
+using B = Dune::FieldMatrix<double, 2, 2>;
+using M = Dune::BCRSMatrix<B>;
+using V = Dune::BlockVector<Dune::FieldVector<double, 2>>;
+
+M build3x3BlockMatrix()
+{
+    // Build matrix with this pattern:
+    //   ( x     ) 
+    //   (   x   )
+    //   (   x x )
+    M res(3, 3, 4, M::row_wise);
+    for (auto row = res.createbegin(); row != res.createend(); ++row) {
+        row.insert(row.index());
+        if (row.index() == 2) {
+            row.insert(1);
+        }
+    }
+    // Set all entries to the block (1, 2; 3, x), where x starts at 4
+    // but gets incremented for each entry.
+    B b;
+    b[0][0] = 1.0;
+    b[0][1] = 2.0;
+    b[1][0] = 3.0;
+    b[1][1] = 4.0;
+    res[0][0] = b;
+    b[1][1] = b[1][1] + 1.0;
+    res[1][1] = b;
+    b[1][1] = b[1][1] + 1.0;
+    res[2][2] = b;
+    b[1][1] = b[1][1] + 1.0;
+    res[2][1] = b;
+
+    return res;
+}
+
+BOOST_AUTO_TEST_CASE(extractMatrix)
+{
+    auto m1 = build3x3BlockMatrix();
+    BOOST_CHECK_EQUAL(m1[2][1][1][1], 7.0);
+    std::vector<int> indices = {1, 2};
+    auto m2 = Opm::Details::extractMatrix(m1, indices);
+    BOOST_CHECK_EQUAL(m2[0][0], m1[1][1]);
+    BOOST_CHECK_EQUAL(m2[1][1], m1[2][2]);
+    BOOST_CHECK_EQUAL(m2[1][0], m1[2][1]);
+}
+
+BOOST_AUTO_TEST_CASE(copySubMatrixAndMatrixEqual)
+{
+    auto m1 = build3x3BlockMatrix();
+    std::vector<int> indices = {1, 2};
+    auto m2 = Opm::Details::extractMatrix(m1, indices);
+    m1[2][1][0][0] = 0.1234;
+    auto m3 = Opm::Details::extractMatrix(m1, indices);
+    BOOST_CHECK(m2[1][0] != m1[2][1]);
+    BOOST_CHECK(m3[1][0] == m1[2][1]);
+    BOOST_CHECK(!Opm::Details::matrixEqual(m2, m3));
+    Opm::Details::copySubMatrix(m1, indices, m2);
+    BOOST_CHECK(Opm::Details::matrixEqual(m2, m3));
+}
+
+BOOST_AUTO_TEST_CASE(vectorOps)
+{
+    V v1(4);
+    v1[0] = { 0.1, 0.2 };
+    v1[1] = { 0.3, 0.4 };
+    v1[2] = { 0.5, 0.6 };
+    v1[3] = { 0.6, 0.8 };
+    std::vector<int> indices = { 0, 2, 3 };
+
+    V vref(3);
+    vref[0] = { 0.1, 0.2 };
+    vref[1] = { 0.5, 0.6 };
+    vref[2] = { 0.6, 0.8 };
+
+    auto v2 = Opm::Details::extractVector(v1, indices);
+    BOOST_CHECK_EQUAL_COLLECTIONS(vref.begin(), vref.end(), v2.begin(), v2.end());
+
+    V v3 = v1;
+    v3[2] = { 1.1, 1.2 };
+    v2[1] = { 1.1, 1.2 };
+    Opm::Details::setGlobal(v2, indices, v1);
+    BOOST_CHECK_EQUAL_COLLECTIONS(v1.begin(), v1.end(), v3.begin(), v3.end());
+}

tests/test_partitionCells.cpp

@@ -0,0 +1,59 @@
+/*
+  Copyright 2021 SINTEF Digital, Mathematics and Cybernetics.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM 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 3 of the License, or
+  (at your option) any later version.
+
+  OPM 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 OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <config.h>
+
+#define BOOST_TEST_MODULE OPM_test_aspinPartition
+#include <boost/test/unit_test.hpp>
+
+#include <opm/simulators/flow/partitionCells.hpp>
+
+
+BOOST_AUTO_TEST_CASE(FileBased)
+{
+    auto [part, num_part] = Opm::partitionCellsFromFile("test10.partition", 10);
+    BOOST_CHECK_EQUAL(num_part, 3);
+    std::vector<int> expected = { 0, 0, 1, 1, 2, 2, 1, 1, 0, 0 };
+    BOOST_CHECK_EQUAL_COLLECTIONS(expected.begin(), expected.end(), part.begin(), part.end());
+}
+
+BOOST_AUTO_TEST_CASE(FileBasedWrongNumberOfCells)
+{
+    auto func = []() { auto [part, num_part] = Opm::partitionCellsFromFile("test10.partition", 11); };
+    BOOST_CHECK_THROW(func(), std::runtime_error);
+}
+
+BOOST_AUTO_TEST_CASE(Simple1)
+{
+    auto [part, num_part]  = Opm::partitionCellsSimple(10, 3);
+    BOOST_CHECK_EQUAL(num_part, 3);
+    std::vector<int> expected = { 0, 0, 0, 0, 1, 1, 1, 2, 2, 2 };
+    BOOST_CHECK_EQUAL_COLLECTIONS(expected.begin(), expected.end(), part.begin(), part.end());
+
+}
+
+BOOST_AUTO_TEST_CASE(Simple2)
+{
+    auto [part, num_part]  = Opm::partitionCellsSimple(10, 7);
+    BOOST_CHECK_EQUAL(num_part, 7);
+    std::vector<int> expected = { 0, 0, 1, 1, 2, 2, 3, 4, 5, 6 };
+    BOOST_CHECK_EQUAL_COLLECTIONS(expected.begin(), expected.end(), part.begin(), part.end());
+
+}
+