opm-simulators/tests/test_dilu.cpp
2023-11-02 12:14:10 +01:00

789 lines
22 KiB
C++

/*
Copyright 2022-2023 SINTEF AS
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/>.
*/
#define BOOST_TEST_MODULE TestSeqDILU
#include <config.h>
#include <opm/simulators/linalg/DILU.hpp>
#include <boost/mpl/list.hpp>
#include <boost/test/unit_test.hpp>
#include <dune/common/fmatrix.hh>
#include <dune/istl/bcrsmatrix.hh>
#include <dune/istl/preconditioners.hh>
using NumericTypes = boost::mpl::list<double, float>;
BOOST_AUTO_TEST_CASE_TEMPLATE(SeqDILUDiagIsCorrect2x2NoZeros, T, NumericTypes)
{
/*
Tests that the dilu decomposition mathces the expected result
for a 2x2 matrix with no zero blocks, with block size 2x2.
A
| | 3 1| | 1 0| |
| | 2 1| | 0 1| |
| |
| | 2 0| |-1 0| |
| | 0 2| | 0 -1| |
*/
const int N = 2;
constexpr int bz = 2;
const int nonZeroes = 4;
using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, bz, bz>>;
using Vector = Dune::BlockVector<Dune::FieldVector<double, bz>>;
Matrix A(N, N, nonZeroes, Matrix::row_wise);
for (auto row = A.createbegin(); row != A.createend(); ++row) {
row.insert(0);
row.insert(1);
}
A[0][0][0][0]=3.0;
A[0][0][0][1]=1.0;
A[0][0][1][0]=2.0;
A[0][0][1][1]=1.0;
A[0][1][0][0]=1.0;
A[0][1][1][1]=1.0;
A[1][0][0][0]=2.0;
A[1][0][1][1]=2.0;
A[1][1][0][0]=-1.0;
A[1][1][1][1]=-1.0;
auto D_00 = A[0][0];
auto D_00_inv = D_00;
D_00_inv.invert();
// D_11 = A_11 - L_10 D_00_inv U_01
auto D_11 = A[1][1] - A[1][0]*D_00_inv*A[0][1];
Dune::SeqDilu<Matrix, Vector, Vector> seqdilu(A);
auto Dinv = seqdilu.getDiagonal();
// diagonal stores inverse
auto D_00_dilu = Dinv[0];
D_00_dilu.invert();
auto D_11_dilu = Dinv[1];
D_11_dilu.invert();
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
BOOST_CHECK_CLOSE(D_00_dilu[i][j], D_00[i][j], 1e-7);
BOOST_CHECK_CLOSE(D_11_dilu[i][j], D_11[i][j], 1e-7);
}
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(SeqDILUDiagIsCorrect2x2, T, NumericTypes)
{
/*
Tests that the dilu decomposition mathces the expected result
for a 2x2 matrix, with block size 2x2.
A
| | 3 1| | 1 0| |
| | 2 1| | 0 1| |
| |
| | 0 0| |-1 0| |
| | 0 0| | 0 -1| |
*/
const int N = 2;
constexpr int bz = 2;
const int nonZeroes = 3;
using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, bz, bz>>;
using Vector = Dune::BlockVector<Dune::FieldVector<double, bz>>;
Matrix A(N, N, nonZeroes, Matrix::row_wise);
for (auto row = A.createbegin(); row != A.createend(); ++row) {
row.insert(row.index());
if (row.index() == 0) {
row.insert(row.index() + 1);
}
}
A[0][0][0][0]=3.0;
A[0][0][0][1]=1.0;
A[0][0][1][0]=2.0;
A[0][0][1][1]=1.0;
A[0][1][0][0]=1.0;
A[0][1][1][1]=1.0;
A[1][1][0][0]=-1.0;
A[1][1][1][1]=-1.0;
auto D_00 = A[0][0];
auto D_00_inv = D_00;
D_00_inv.invert();
// D_11 = A_11 - L_10 D_00_inv U_01 = A_11
auto D_11 = A[1][1];
Dune::SeqDilu<Matrix, Vector, Vector> seqdilu(A);
auto Dinv = seqdilu.getDiagonal();
// diagonal stores inverse
auto D_00_dilu = Dinv[0];
D_00_dilu.invert();
auto D_11_dilu = Dinv[1];
D_11_dilu.invert();
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
BOOST_CHECK_CLOSE(D_00_dilu[i][j], D_00[i][j], 1e-7);
BOOST_CHECK_CLOSE(D_11_dilu[i][j], D_11[i][j], 1e-7);
}
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(SeqDILUApplyIsCorrectNoZeros, T, NumericTypes)
{
/*
Tests that applying the dilu preconditioner mathces the expected result
for a 2x2 matrix with no zero blocks, with block size 2x2.
A x = b
| | 3 1| | 1 0| | | |1| | | |2| |
| | 2 1| | 0 1| | | |2| | | |1| |
| | x | | = | |
| | 2 0| |-1 0| | | |1| | | |3| |
| | 0 2| | 0 -1| | | |1| | | |4| |
*/
const int N = 2;
constexpr int bz = 2;
const int nonZeroes = 4;
using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, bz, bz>>;
using Vector = Dune::BlockVector<Dune::FieldVector<double, bz>>;
Matrix A(N, N, nonZeroes, Matrix::row_wise);
for (auto row = A.createbegin(); row != A.createend(); ++row) {
row.insert(0);
row.insert(1);
}
A[0][0][0][0]=3.0;
A[0][0][0][1]=1.0;
A[0][0][1][0]=2.0;
A[0][0][1][1]=1.0;
A[0][1][0][0]=1.0;
A[0][1][1][1]=1.0;
A[1][0][0][0]=2.0;
A[1][0][1][1]=2.0;
A[1][1][0][0]=-1.0;
A[1][1][1][1]=-1.0;
Vector x(2);
x[0][0] = 1.0;
x[0][1] = 2.0;
x[1][0] = 1.0;
x[1][1] = 1.0;
Vector b(2);
b[0][0] = 2.0;
b[0][1] = 1.0;
b[1][0] = 3.0;
b[1][1] = 4.0;
auto D_00 = A[0][0];
auto D_00_inv = D_00;
D_00_inv.invert();
// D_11= A_11 - L_10 D_00_inv U_01
auto D_11 = A[1][1] - A[1][0]*D_00_inv*A[0][1];
auto D_11_inv = D_11;
D_11_inv.invert();
// define: z = M^-1(b - Ax)
// where: M = (D + L_A) A^-1 (D + U_A)
// lower triangular solve: (E + L) y = b - Ax
// y_0 = D_00_inv*[b_0 - (A_00*x_0 + A_01*x_1)]
Vector y(2);
auto rhs = b[0];
A[0][0].mmv(x[0], rhs);
A[0][1].mmv(x[1], rhs);
D_00_inv.mv(rhs, y[0]);
// y_1 = D_11_inv*(b_1 - (A_10*x_0 + A_11*x_1) - A_10*y_0)
rhs = b[1];
A[1][0].mmv(x[0], rhs);
A[1][1].mmv(x[1], rhs);
A[1][0].mmv(y[0], rhs);
D_11_inv.mv(rhs, y[1]);
// upper triangular solve: (E + U) z = Ey
// z_1 = y_1
Vector z(2);
z[1] = y[1];
// z_0 = y_0 - D_00_inv*A_01*z_1
z[0] = y[0];
auto temp = D_00_inv*A[0][1];
temp.mmv(z[1], z[0]);
// x_k+1 = x_k + z
Vector new_x = x;
new_x += z;
Dune::SeqDilu<Matrix, Vector, Vector> seqdilu(A);
seqdilu.apply(x, b);
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
BOOST_CHECK_CLOSE(x[i][j], new_x[i][j], 1e-7);
}
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(SeqDILUApplyIsCorrect1, T, NumericTypes)
{
/*
Tests that applying the dilu preconditioner mathces the expected result
for a 2x2 matrix, with block size 2x2.
A x = b
| | 3 1| | 1 0| | | |1| | | |2| |
| | 2 1| | 0 1| | | |2| | | |1| |
| | x | | = | |
| | 0 0| |-1 0| | | |1| | | |3| |
| | 0 0| | 0 -1| | | |1| | | |4| |
*/
const int N = 2;
constexpr int bz = 2;
const int nonZeroes = 3;
using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, bz, bz>>;
using Vector = Dune::BlockVector<Dune::FieldVector<double, bz>>;
Matrix A(N, N, nonZeroes, Matrix::row_wise);
for (auto row = A.createbegin(); row != A.createend(); ++row) {
row.insert(row.index());
if (row.index() == 0) {
row.insert(row.index() + 1);
}
}
A[0][0][0][0]=3.0;
A[0][0][0][1]=1.0;
A[0][0][1][0]=2.0;
A[0][0][1][1]=1.0;
A[0][1][0][0]=1.0;
A[0][1][1][1]=1.0;
A[1][1][0][0]=-1.0;
A[1][1][1][1]=-1.0;
Vector x(2);
x[0][0] = 1.0;
x[0][1] = 2.0;
x[1][0] = 1.0;
x[1][1] = 1.0;
Vector b(2);
b[0][0] = 2.0;
b[0][1] = 1.0;
b[1][0] = 3.0;
b[1][1] = 4.0;
auto D_00 = A[0][0];
auto D_00_inv = D_00;
D_00_inv.invert();
// D_11 = A_11 - L_10 D_0_inv U_01 = A_11
auto D_11 = A[1][1];
auto D_11_inv = D_11;
D_11_inv.invert();
// define: z = M^-1(b - Ax)
// where: M = (D + L_A) A^-1 (D + U_A)
// lower triangular solve: (E + L) y = b - Ax
// y_0 = D_00_inv*[b_0 - (A_00*x_0 + A_01*x_1)]
Vector y(2);
auto rhs = b[0];
A[0][0].mmv(x[0], rhs);
A[0][1].mmv(x[1], rhs);
D_00_inv.mv(rhs, y[0]);
// y_1 = D_11_inv*(b_1 - (A_10*x_0 + A_11*x_1) - A_10*y_0) = D_11_inv*(b_1 - A_11*x_1)
rhs = b[1];
A[1][1].mmv(x[1], rhs);
D_11_inv.mv(rhs, y[1]);
// upper triangular solve: (E + U) z = Ey
// z_1 = y_1
Vector z(2);
z[1] = y[1];
// z_0 = y_0 - D_00_inv*A_01*z_1
z[0] = y[0];
auto temp = D_00_inv*A[0][1];
temp.mmv(z[1], z[0]);
// x_k+1 = x_k + z
Vector new_x = x;
new_x += z;
Dune::SeqDilu<Matrix, Vector, Vector> seqdilu(A);
seqdilu.apply(x, b);
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
BOOST_CHECK_CLOSE(x[i][j], new_x[i][j], 1e-7);
}
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(SeqDILUApplyIsCorrect2, T, NumericTypes)
{
/*
Tests that applying the dilu preconditioner mathces the expected result
for a 2x2 matrix, with block size 2x2.
A x = b
| | 3 1| | 0 0| | | |1| | | |2| |
| | 2 1| | 0 0| | | |2| | | |1| |
| | x | | = | |
| | 2 0| |-1 0| | | |1| | | |3| |
| | 0 2| | 0 -1| | | |1| | | |4| |
*/
const int N = 2;
constexpr int bz = 2;
const int nonZeroes = 3;
using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, bz, bz>>;
using Vector = Dune::BlockVector<Dune::FieldVector<double, bz>>;
Matrix A(N, N, nonZeroes, Matrix::row_wise);
for (auto row = A.createbegin(); row != A.createend(); ++row) {
row.insert(row.index());
if (row.index() == 1) {
row.insert(row.index() - 1);
}
}
A[0][0][0][0]=3.0;
A[0][0][0][1]=1.0;
A[0][0][1][0]=2.0;
A[0][0][1][1]=1.0;
A[1][1][0][0]=2.0;
A[1][1][1][1]=2.0;
A[1][1][0][0]=-1.0;
A[1][1][1][1]=-1.0;
Vector x(2);
x[0][0] = 1.0;
x[0][1] = 2.0;
x[1][0] = 1.0;
x[1][1] = 1.0;
Vector b(2);
b[0][0] = 2.0;
b[0][1] = 1.0;
b[1][0] = 3.0;
b[1][1] = 4.0;
auto D_00 = A[0][0];
auto D_00_inv = D_00;
D_00_inv.invert();
// D_11 = A_11 - L_10 D_0_inv U_01 = A_11
auto D_11 = A[1][1];
auto D_11_inv = D_11;
D_11_inv.invert();
// define: z = M^-1(b - Ax)
// where: M = (D + L_A) A^-1 (D + U_A)
// lower triangular solve: (E + L) y = b - Ax
// y_0 = D_00_inv*[b_0 - (A_00*x_0 + A_01*x_1)] = D_00_inv*[b_0 - A_00*x_0]
Vector y(2);
auto rhs = b[0];
A[0][0].mmv(x[0], rhs);
D_00_inv.mv(rhs, y[0]);
// y_1 = D_11_inv*(b_1 - (A_10*x_0 + A_11*x_1) - A_10*y_0)
rhs = b[1];
A[1][1].mmv(x[1], rhs);
D_11_inv.mv(rhs, y[1]);
// upper triangular solve: (E + U) z = Ey
// z_1 = y_1
Vector z(2);
z[1] = y[1];
// z_0 = y_0 - D_00_inv*A_01*z_1 = y_0
z[0] = y[0];
// x_k+1 = x_k + z
Vector new_x = x;
new_x += z;
Dune::SeqDilu<Matrix, Vector, Vector> seqdilu(A);
seqdilu.apply(x, b);
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
BOOST_CHECK_CLOSE(x[i][j], new_x[i][j], 1e-7);
}
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(SeqDILUDiagIsCorrect3x3, T, NumericTypes)
{
/*
Tests that the dilu decomposition mathces the expected result
for a 3x3 matrix, with block size 3x3.
A
| | 3 1 2| | 0 0 0| | 0 0 0| |
| | 2 3 1| | 0 0 0| | 0 0 0| |
| | 2 1 0| | 0 0 0| | 0 0 0| |
| |
| | 0 0 0| | 1 0 1| | 1 0 2| |
| | 0 0 0| | 4 1 0| | 0 1 1| |
| | 0 0 0| | 3 1 3| | 0 1 3| |
| |
| | 0 0 0| | 1 0 2| | 1 3 2| |
| | 0 0 0| | 0 1 4| | 2 1 3| |
| | 0 0 0| | 5 1 1| | 3 1 2| |
*/
const int N = 3;
constexpr int bz = 3;
const int nonZeroes = 5;
using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, bz, bz>>;
using Vector = Dune::BlockVector<Dune::FieldVector<double, bz>>;
Matrix A(N, N, nonZeroes, Matrix::row_wise);
for (auto row = A.createbegin(); row != A.createend(); ++row) {
if (row.index() == 0) {
row.insert(row.index());
}
else if (row.index() == 1) {
row.insert(row.index());
row.insert(row.index() + 1);
}
else if (row.index() == 2) {
row.insert(row.index() - 1);
row.insert(row.index());
}
}
A[0][0][0][0]=3.0; A[1][1][0][0]=1.0; A[1][2][0][0]=1.0;
A[0][0][0][1]=1.0; A[1][1][0][1]=0.0; A[1][2][0][1]=0.0;
A[0][0][0][2]=2.0; A[1][1][0][2]=1.0; A[1][2][0][2]=2.0;
A[0][0][1][0]=2.0; A[1][1][1][0]=4.0; A[1][2][1][0]=0.0;
A[0][0][1][1]=3.0; A[1][1][1][1]=1.0; A[1][2][1][1]=1.0;
A[0][0][1][2]=1.0; A[1][1][1][2]=0.0; A[1][2][1][2]=1.0;
A[0][0][2][0]=2.0; A[1][1][2][0]=3.0; A[1][2][2][0]=0.0;
A[0][0][2][1]=1.0; A[1][1][2][1]=1.0; A[1][2][2][1]=1.0;
A[0][0][2][2]=0.0; A[1][1][2][2]=3.0; A[1][2][2][2]=3.0;
A[2][1][0][0]=1.0; A[2][2][0][0]=1.0;
A[2][1][0][1]=0.0; A[2][2][0][1]=3.0;
A[2][1][0][2]=2.0; A[2][2][0][2]=2.0;
A[2][1][1][0]=0.0; A[2][2][1][0]=2.0;
A[2][1][1][1]=1.0; A[2][2][1][1]=1.0;
A[2][1][1][2]=4.0; A[2][2][1][2]=3.0;
A[2][1][2][0]=5.0; A[2][2][2][0]=3.0;
A[2][1][2][1]=1.0; A[2][2][2][1]=1.0;
A[2][1][2][2]=1.0; A[2][2][2][2]=2.0;
auto D_00 = A[0][0];
auto D_00_inv = D_00;
D_00_inv.invert();
// D_11 = A_11 - L_10 D_00_inv U_01 = A_11
auto D_11 = A[1][1];
auto D_11_inv = D_11;
D_11_inv.invert();
// D_22 = A_22 - A_20 D_00_inv A_02 - A_21 D_11_inv A_12 = A_22 - A_21 D_11_inv A_12
auto D_22 = A[2][2] - A[2][1]*D_11_inv*A[1][2];
auto D_22_inv = D_22;
D_22_inv.invert();
Dune::SeqDilu<Matrix, Vector, Vector> seqdilu(A);
auto Dinv = seqdilu.getDiagonal();
// diagonal stores inverse
auto D_00_dilu = Dinv[0];
D_00_dilu.invert();
auto D_11_dilu = Dinv[1];
D_11_dilu.invert();
auto D_22_dilu = Dinv[2];
D_22_dilu.invert();
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 3; ++j) {
BOOST_CHECK_CLOSE(D_00_dilu[i][j], D_00[i][j], 1e-7);
BOOST_CHECK_CLOSE(D_11_dilu[i][j], D_11[i][j], 1e-7);
BOOST_CHECK_CLOSE(D_22_dilu[i][j], D_22[i][j], 1e-7);
}
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(SeqDILUApplyIsCorrect3, T, NumericTypes)
{
/*
Tests that applying the dilu preconditioner mathces the expected result
for a 3x3 matrix, with block size 3x3.
A x = b
| | 3 1 2| | 0 0 0| | 0 0 0| | | |1| | | |2| |
| | 2 3 1| | 0 0 0| | 0 0 0| | | |2| | | |1| |
| | 2 1 0| | 0 0 0| | 0 0 0| | | |3| | | |2| |
| | | | | |
| | 0 0 0| | 1 0 1| | 1 0 2| | | |1| | | |2| |
| | 0 0 0| | 4 1 0| | 0 1 1| | x | |3| | = | |3| |
| | 0 0 0| | 3 1 3| | 0 1 3| | | |2| | | |2| |
| | | | | |
| | 0 0 0| | 1 0 2| | 1 3 2| | | |1| | | |0| |
| | 0 0 0| | 0 1 4| | 2 1 3| | | |0| | | |2| |
| | 0 0 0| | 5 1 1| | 3 1 2| | | |2| | | |1| |
*/
const int N = 3;
constexpr int bz = 3;
const int nonZeroes = 5;
using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, bz, bz>>;
using Vector = Dune::BlockVector<Dune::FieldVector<double, bz>>;
Matrix A(N, N, nonZeroes, Matrix::row_wise);
for (auto row = A.createbegin(); row != A.createend(); ++row) {
if (row.index() == 0) {
row.insert(row.index());
}
else if (row.index() == 1) {
row.insert(row.index());
row.insert(row.index() + 1);
}
else if (row.index() == 2) {
row.insert(row.index() - 1);
row.insert(row.index());
}
}
A[0][0][0][0]=3.0; A[1][1][0][0]=1.0; A[1][2][0][0]=1.0;
A[0][0][0][1]=1.0; A[1][1][0][1]=0.0; A[1][2][0][1]=0.0;
A[0][0][0][2]=2.0; A[1][1][0][2]=1.0; A[1][2][0][2]=2.0;
A[0][0][1][0]=2.0; A[1][1][1][0]=4.0; A[1][2][1][0]=0.0;
A[0][0][1][1]=3.0; A[1][1][1][1]=1.0; A[1][2][1][1]=1.0;
A[0][0][1][2]=1.0; A[1][1][1][2]=0.0; A[1][2][1][2]=1.0;
A[0][0][2][0]=2.0; A[1][1][2][0]=3.0; A[1][2][2][0]=0.0;
A[0][0][2][1]=1.0; A[1][1][2][1]=1.0; A[1][2][2][1]=1.0;
A[0][0][2][2]=0.0; A[1][1][2][2]=3.0; A[1][2][2][2]=3.0;
A[2][1][0][0]=1.0; A[2][2][0][0]=1.0;
A[2][1][0][1]=0.0; A[2][2][0][1]=3.0;
A[2][1][0][2]=2.0; A[2][2][0][2]=2.0;
A[2][1][1][0]=0.0; A[2][2][1][0]=2.0;
A[2][1][1][1]=1.0; A[2][2][1][1]=1.0;
A[2][1][1][2]=4.0; A[2][2][1][2]=3.0;
A[2][1][2][0]=5.0; A[2][2][2][0]=3.0;
A[2][1][2][1]=1.0; A[2][2][2][1]=1.0;
A[2][1][2][2]=1.0; A[2][2][2][2]=2.0;
Vector x(3);
x[0][0] = 1.0; x[1][0] = 1.0; x[2][0] = 1.0;
x[0][1] = 2.0; x[1][1] = 3.0; x[2][1] = 0.0;
x[0][2] = 3.0; x[1][2] = 2.0; x[2][2] = 2.0;
Vector b(3);
b[0][0] = 2.0; b[1][0] = 2.0; b[2][0] = 0.0;
b[0][1] = 1.0; b[1][1] = 3.0; b[2][1] = 2.0;
b[0][2] = 2.0; b[1][2] = 2.0; b[2][2] = 1.0;
// D_00 = A_00
auto D_00 = A[0][0];
auto D_00_inv = D_00;
D_00_inv.invert();
// D_11 = A_11 - L_10 D_00_inv U_01
// = A_11
auto D_11 = A[1][1];
auto D_11_inv = D_11;
D_11_inv.invert();
// D_22 = A_22 - A_20 D_00_inv A_02 - A_21 D_11_inv A_12
// = A_22 - A_21 D_11_inv A_12
auto D_22 = A[2][2] - A[2][1]*D_11_inv*A[1][2];
auto D_22_inv = D_22;
D_22_inv.invert();
// define: z = M^-1(b - Ax)
// where: M = (D + L_A) A^-1 (D + U_A)
// lower triangular solve: (E + L) y = b - Ax
Vector y(3);
// y_0 = D_00_inv*[b_0 - (A_00*x_0 + A_01*x_1)]
// = D_00_inv*[b_0 - A_00*x_0]
auto rhs = b[0];
A[0][0].mmv(x[0], rhs);
D_00_inv.mv(rhs, y[0]);
// y_1 = D_11_inv*(b_1 - (A_10*x_0 + A_11*x_1 + A_12*x_2) - A_10*y_0)
// = D_11_inv*(b_1 - A_11*x_1)
rhs = b[1];
A[1][1].mmv(x[1], rhs);
A[1][2].mmv(x[2], rhs);
D_11_inv.mv(rhs, y[1]);
// y_2 = D_22_inv*(b_2 - (A_20*x_0 + A_21*x_1 + A_22*x_2) - (A_20*y_0 + A_21*y_1))
// = D_22_inv*(b_2 - (A_21*x_1 + A_22*x_2) - (A_21*y_1))
rhs = b[2];
A[2][1].mmv(x[1], rhs);
A[2][2].mmv(x[2], rhs);
A[2][1].mmv(y[1], rhs);
D_22_inv.mv(rhs, y[2]);
// upper triangular solve: (E + U) z = Ey
Vector z(3);
// z_2 = y_2
z[2] = y[2];
// z_1 = y_1 - D_11_inv*A_12*z_2
z[1] = y[1];
auto temp = D_11_inv*A[1][2];
temp.mmv(z[2], z[1]);
// z_0 = y_0 - D_00_inv(A_01*z_1 + A_02*z_2)
// z_0 = y_0
z[0] = y[0];
// x_k+1 = x_k + z
Vector new_x = x;
new_x += z;
Dune::SeqDilu<Matrix, Vector, Vector> seqdilu(A);
seqdilu.apply(x, b);
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 3; ++j) {
BOOST_CHECK_CLOSE(x[i][j], new_x[i][j], 1e-7);
}
}
}
BOOST_AUTO_TEST_CASE_TEMPLATE(SeqDILUApplyIsEqualToDuneSeqILUApply, T, NumericTypes)
{
/*
Tests that applying the DILU preconditioner is equivalent to applying a ILU preconditioner
for a block diagonal matrix.
A x = b
| | 3 1| | 0 0| | | |1| | | |2| |
| | 2 1| | 0 0| | | |2| | | |1| |
| | x | | = | |
| | 0 0| |-1 0| | | |1| | | |3| |
| | 0 0| | 0 -1| | | |1| | | |4| |
*/
const int N = 2;
constexpr int bz = 2;
const int nonZeroes = 2;
using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, bz, bz>>;
using Vector = Dune::BlockVector<Dune::FieldVector<double, bz>>;
Matrix A(N, N, nonZeroes, Matrix::row_wise);
for (auto row = A.createbegin(); row != A.createend(); ++row) {
row.insert(row.index());
}
A[0][0][0][0]=3.0;
A[0][0][0][1]=1.0;
A[0][0][1][0]=2.0;
A[0][0][1][1]=1.0;
A[1][1][0][0]=-1.0;
A[1][1][1][1]=-1.0;
Dune::SeqDilu<Matrix, Vector, Vector> seqdilu(A);
Dune::SeqILU<Matrix, Vector, Vector> seqilu(A, 1.0);
Vector dilu_x(2);
dilu_x[0][0] = 1.0;
dilu_x[0][1] = 2.0;
dilu_x[1][0] = 1.0;
dilu_x[1][1] = 1.0;
Vector dilu_b(2);
dilu_b[0][0] = 2.0;
dilu_b[0][1] = 1.0;
dilu_b[1][0] = 3.0;
dilu_b[1][1] = 4.0;
Vector ilu_x(2);
ilu_x[0][0] = 1.0;
ilu_x[0][1] = 2.0;
ilu_x[1][0] = 1.0;
ilu_x[1][1] = 1.0;
Vector ilu_b(2);
ilu_b[0][0] = 2.0;
ilu_b[0][1] = 1.0;
ilu_b[1][0] = 3.0;
ilu_b[1][1] = 4.0;
seqdilu.apply(dilu_x, dilu_b);
seqilu.apply(ilu_x, ilu_b);
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
BOOST_CHECK_CLOSE(dilu_x[i][j], ilu_x[i][j], 1e-7);
}
}
}