opm-core/opm/core/utility/TridiagonalMatrix.hpp

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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*****************************************************************************
* Copyright (C) 2010-2013 by Andreas Lauser *
* *
* 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 *
* MERCHANTBILITY 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
* \copydetails Opm::TridiagonalMatrix
*/
#ifndef OPM_TRIDIAGONAL_MATRIX_HH
#define OPM_TRIDIAGONAL_MATRIX_HH
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <assert.h>
namespace Opm {
/*!
* \brief Provides a tridiagonal matrix that also supports non-zero
* entries in the upper right and lower left
*
* The entries in the lower left and upper right are supported to make
* implementing periodic systems easy.
*
* The API of this class is designed to be close to the one used by
* the DUNE matrix classes.
*/
template <class Scalar>
class TridiagonalMatrix
{
struct TridiagRow_ {
TridiagRow_(TridiagonalMatrix &m, size_t rowIdx)
: matrix_(m)
, rowIdx_(rowIdx)
{};
Scalar &operator[](size_t colIdx)
{ return matrix_.at(rowIdx_, colIdx); }
Scalar operator[](size_t colIdx) const
{ return matrix_.at(rowIdx_, colIdx); }
/*!
* \brief Prefix increment operator
*/
TridiagRow_ &operator++()
{ ++ rowIdx_; return *this; }
/*!
* \brief Prefix decrement operator
*/
TridiagRow_ &operator--()
{ -- rowIdx_; return *this; }
/*!
* \brief Comparision operator
*/
bool operator==(const TridiagRow_ &other) const
{ return other.rowIdx_ == rowIdx_ && &other.matrix_ == &matrix_; }
/*!
* \brief Comparision operator
*/
bool operator!=(const TridiagRow_ &other) const
{ return !operator==(other); }
/*!
* \brief Dereference operator
*/
TridiagRow_ &operator*()
{ return *this; }
/*!
* \brief Return the row index of the this row.
*
* 0 is the first row.
*/
size_t index() const
{ return rowIdx_; }
private:
TridiagonalMatrix &matrix_;
mutable size_t rowIdx_;
};
public:
typedef Scalar FieldType;
typedef TridiagRow_ RowType;
typedef size_t SizeType;
typedef TridiagRow_ iterator;
typedef TridiagRow_ const_iterator;
explicit TridiagonalMatrix(int numRows = 0)
{
resize(numRows);
};
TridiagonalMatrix(int numRows, Scalar value)
{
resize(numRows);
this->operator=(value);
};
/*!
* \brief Copy constructor.
*/
TridiagonalMatrix(const TridiagonalMatrix &source)
{ *this = source; };
/*!
* \brief Return the number of rows/columns of the matrix.
*/
size_t size() const
{ return diag_[0].size(); }
/*!
* \brief Return the number of rows of the matrix.
*/
size_t rows() const
{ return size(); }
/*!
* \brief Return the number of columns of the matrix.
*/
size_t cols() const
{ return size(); }
/*!
* \brief Change the number of rows of the matrix.
*/
void resize(size_t n)
{
if (n == size())
return;
for (int diagIdx = 0; diagIdx < 3; ++ diagIdx)
diag_[diagIdx].resize(n);
}
/*!
* \brief Access an entry.
*/
Scalar &at(size_t rowIdx, size_t colIdx)
{
size_t n = size();
// special cases
if (n > 2) {
if (rowIdx == 0 && colIdx == n - 1)
return diag_[2][0];
if (rowIdx == n - 1 && colIdx == 0)
return diag_[0][n - 1];
}
int diagIdx = 1 + colIdx - rowIdx;
// make sure that the requested column is in range
assert(0 <= diagIdx && diagIdx < 3);
return diag_[diagIdx][colIdx];
}
/*!
* \brief Access an entry.
*/
Scalar at(size_t rowIdx, size_t colIdx) const
{
int n = size();
// special cases
if (rowIdx == 0 && colIdx == n - 1)
return diag_[2][0];
if (rowIdx == n - 1 && colIdx == 0)
return diag_[0][n - 1];
int diagIdx = 1 + colIdx - rowIdx;
// make sure that the requested column is in range
assert(0 <= diagIdx && diagIdx < 3);
return diag_[diagIdx][colIdx];
}
/*!
* \brief Assignment operator from another tridiagonal matrix.
*/
TridiagonalMatrix &operator=(const TridiagonalMatrix &source)
{
for (int diagIdx = 0; diagIdx < 3; ++ diagIdx)
diag_[diagIdx] = source.diag_[diagIdx];
return *this;
}
/*!
* \brief Assignment operator from a Scalar.
*/
TridiagonalMatrix &operator=(Scalar value)
{
for (int diagIdx = 0; diagIdx < 3; ++ diagIdx)
diag_[diagIdx].assign(size(), value);
return *this;
}
/*!
* \begin Iterator for the first row
*/
iterator begin()
{ return TridiagRow_(*this, 0); }
/*!
* \begin Const iterator for the first row
*/
const_iterator begin() const
{ return TridiagRow_(const_cast<TridiagonalMatrix&>(*this), 0); }
/*!
* \begin Const iterator for the next-to-last row
*/
const_iterator end() const
{ return TridiagRow_(const_cast<TridiagonalMatrix&>(*this), size()); }
/*!
* \brief Row access operator.
*/
TridiagRow_ operator[](size_t rowIdx)
{ return TridiagRow_(*this, rowIdx); }
/*!
* \brief Row access operator.
*/
const TridiagRow_ operator[](size_t rowIdx) const
{ return TridiagRow_(*this, rowIdx); }
/*!
* \brief Multiplication with a Scalar
*/
TridiagonalMatrix &operator*=(Scalar alpha)
{
int n = size();
for (int diagIdx = 0; diagIdx < 3; ++ diagIdx) {
for (int i = 0; i < n; ++i) {
diag_[diagIdx][i] *= alpha;
}
}
return *this;
}
/*!
* \brief Division by a Scalar
*/
TridiagonalMatrix &operator/=(Scalar alpha)
{
alpha = 1.0/alpha;
int n = size();
for (int diagIdx = 0; diagIdx < 3; ++ diagIdx) {
for (int i = 0; i < n; ++i) {
diag_[diagIdx][i] *= alpha;
}
}
return *this;
}
/*!
* \brief Subtraction operator
*/
TridiagonalMatrix &operator-=(const TridiagonalMatrix &other)
{ return axpy(-1.0, other); }
/*!
* \brief Addition operator
*/
TridiagonalMatrix &operator+=(const TridiagonalMatrix &other)
{ return axpy(1.0, other); }
/*!
* \brief Multiply and add the matrix entries of another
* tridiagonal matrix.
*
* This means that
* \code
* A.axpy(alpha, B)
* \endcode
* is equivalent to
* \code
* A += alpha*C
* \endcode
*/
TridiagonalMatrix &axpy(Scalar alpha, const TridiagonalMatrix &other)
{
assert(size() == other.size());
int n = size();
for (int diagIdx = 0; diagIdx < 3; ++ diagIdx)
for (int i = 0; i < n; ++ i)
diag_[diagIdx][i] += alpha * other[diagIdx][i];
return *this;
}
/*!
* \brief Matrix-vector product
*
* This means that
* \code
* A.mv(x, y)
* \endcode
* is equivalent to
* \code
* y = A*x
* \endcode
*/
template<class Vector>
void mv(const Vector &source, Vector &dest) const
{
assert(source.size() == size());
assert(dest.size() == size());
assert(size() > 1);
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
dest[i] =
diag_[0][i - 1]*source[i-1] +
diag_[1][i]*source[i] +
diag_[2][i + 1]*source[i + 1];
}
// rows 0 and n-1
dest[0] =
diag_[1][0]*source[0] +
diag_[2][1]*source[1] +
diag_[2][0]*source[n - 1];
dest[n - 1] =
diag_[0][n-1]*source[0] +
diag_[0][n-2]*source[n-2] +
diag_[1][n-1]*source[n-1];
}
/*!
* \brief Additive matrix-vector product
*
* This means that
* \code
* A.umv(x, y)
* \endcode
* is equivalent to
* \code
* y += A*x
* \endcode
*/
template<class Vector>
void umv(const Vector &source, Vector &dest) const
{
assert(source.size() == size());
assert(dest.size() == size());
assert(size() > 1);
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
dest[i] +=
diag_[0][i - 1]*source[i-1] +
diag_[1][i]*source[i] +
diag_[2][i + 1]*source[i + 1];
}
// rows 0 and n-1
dest[0] +=
diag_[1][0]*source[0] +
diag_[2][1]*source[1] +
diag_[2][0]*source[n - 1];
dest[n - 1] +=
diag_[0][n-1]*source[0] +
diag_[0][n-2]*source[n-2] +
diag_[1][n-1]*source[n-1];
}
/*!
* \brief Subtractive matrix-vector product
*
* This means that
* \code
* A.mmv(x, y)
* \endcode
* is equivalent to
* \code
* y -= A*x
* \endcode
*/
template<class Vector>
void mmv(const Vector &source, Vector &dest) const
{
assert(source.size() == size());
assert(dest.size() == size());
assert(size() > 1);
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
dest[i] -=
diag_[0][i - 1]*source[i-1] +
diag_[1][i]*source[i] +
diag_[2][i + 1]*source[i + 1];
}
// rows 0 and n-1
dest[0] -=
diag_[1][0]*source[0] +
diag_[2][1]*source[1] +
diag_[2][0]*source[n - 1];
dest[n - 1] -=
diag_[0][n-1]*source[0] +
diag_[0][n-2]*source[n-2] +
diag_[1][n-1]*source[n-1];
}
/*!
* \brief Scaled additive matrix-vector product
*
* This means that
* \code
* A.usmv(x, y)
* \endcode
* is equivalent to
* \code
* y += alpha*(A*x)
* \endcode
*/
template<class Vector>
void usmv(Scalar alpha, const Vector &source, Vector &dest) const
{
assert(source.size() == size());
assert(dest.size() == size());
assert(size() > 1);
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
dest[i] +=
alpha*(
diag_[0][i - 1]*source[i-1] +
diag_[1][i]*source[i] +
diag_[2][i + 1]*source[i + 1]);
}
// rows 0 and n-1
dest[0] +=
alpha*(
diag_[1][0]*source[0] +
diag_[2][1]*source[1] +
diag_[2][0]*source[n - 1]);
dest[n - 1] +=
alpha*(
diag_[0][n-1]*source[0] +
diag_[0][n-2]*source[n-2] +
diag_[1][n-1]*source[n-1]);
}
/*!
* \brief Transposed matrix-vector product
*
* This means that
* \code
* A.mtv(x, y)
* \endcode
* is equivalent to
* \code
* y = A^T*x
* \endcode
*/
template<class Vector>
void mtv(const Vector &source, Vector &dest) const
{
assert(source.size() == size());
assert(dest.size() == size());
assert(size() > 1);
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
dest[i] =
diag_[2][i + 1]*source[i-1] +
diag_[1][i]*source[i] +
diag_[0][i - 1]*source[i + 1];
}
// rows 0 and n-1
dest[0] =
diag_[1][0]*source[0] +
diag_[0][1]*source[1] +
diag_[0][n-1]*source[n - 1];
dest[n - 1] =
diag_[2][0]*source[0] +
diag_[2][n-1]*source[n-2] +
diag_[1][n-1]*source[n-1];
}
/*!
* \brief Transposed additive matrix-vector product
*
* This means that
* \code
* A.umtv(x, y)
* \endcode
* is equivalent to
* \code
* y += A^T*x
* \endcode
*/
template<class Vector>
void umtv(const Vector &source, Vector &dest) const
{
assert(source.size() == size());
assert(dest.size() == size());
assert(size() > 1);
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
dest[i] +=
diag_[2][i + 1]*source[i-1] +
diag_[1][i]*source[i] +
diag_[0][i - 1]*source[i + 1];
}
// rows 0 and n-1
dest[0] +=
diag_[1][0]*source[0] +
diag_[0][1]*source[1] +
diag_[0][n-1]*source[n - 1];
dest[n - 1] +=
diag_[2][0]*source[0] +
diag_[2][n-1]*source[n-2] +
diag_[1][n-1]*source[n-1];
}
/*!
* \brief Transposed subtractive matrix-vector product
*
* This means that
* \code
* A.mmtv(x, y)
* \endcode
* is equivalent to
* \code
* y -= A^T*x
* \endcode
*/
template<class Vector>
void mmtv (const Vector &source, Vector &dest) const
{
assert(source.size() == size());
assert(dest.size() == size());
assert(size() > 1);
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
dest[i] -=
diag_[2][i + 1]*source[i-1] +
diag_[1][i]*source[i] +
diag_[0][i - 1]*source[i + 1];
}
// rows 0 and n-1
dest[0] -=
diag_[1][0]*source[0] +
diag_[0][1]*source[1] +
diag_[0][n-1]*source[n - 1];
dest[n - 1] -=
diag_[2][0]*source[0] +
diag_[2][n-1]*source[n-2] +
diag_[1][n-1]*source[n-1];
}
/*!
* \brief Transposed scaled additive matrix-vector product
*
* This means that
* \code
* A.umtv(alpha, x, y)
* \endcode
* is equivalent to
* \code
* y += alpha*A^T*x
* \endcode
*/
template<class Vector>
void usmtv(Scalar alpha, const Vector &source, Vector &dest) const
{
assert(source.size() == size());
assert(dest.size() == size());
assert(size() > 1);
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
dest[i] +=
alpha*(
diag_[2][i + 1]*source[i-1] +
diag_[1][i]*source[i] +
diag_[0][i - 1]*source[i + 1]);
}
// rows 0 and n-1
dest[0] +=
alpha*(
diag_[1][0]*source[0] +
diag_[0][1]*source[1] +
diag_[0][n-1]*source[n - 1]);
dest[n - 1] +=
alpha*(
diag_[2][0]*source[0] +
diag_[2][n-1]*source[n-2] +
diag_[1][n-1]*source[n-1]);
}
/*!
* \brief Calculate the frobenius norm
*
* i.e., the square root of the sum of all squared entries. This
* corresponds to the euclidean norm for vectors.
*/
Scalar frobeniusNorm() const
{ return std::sqrt(frobeniusNormSquared()); }
/*!
* \brief Calculate the squared frobenius norm
*
* i.e., the sum of all squared entries.
*/
Scalar frobeniusNormSquared() const
{
Scalar result = 0;
int n = size();
for (int i = 0; i < n; ++ i)
for (int diagIdx = 0; diagIdx < 3; ++ diagIdx)
result += diag_[diagIdx][i];
return result;
}
/*!
* \brief Calculate the infinity norm
*
* i.e., the maximum of the sum of the absolute values of all rows.
*/
Scalar infinityNorm() const
{
Scalar result=0;
// deal with rows 1 .. n-2
int n = size();
for (int i = 1; i < n - 1; ++ i) {
result = std::max(result,
std::abs(diag_[0][i - 1]) +
std::abs(diag_[1][i]) +
std::abs(diag_[2][i + 1]));
}
// rows 0 and n-1
result = std::max(result,
std::abs(diag_[1][0]) +
std::abs(diag_[2][1]) +
std::abs(diag_[2][0]));
result = std::max(result,
std::abs(diag_[0][n-1]) +
std::abs(diag_[0][n-2]) +
std::abs(diag_[1][n-2]));
return result;
}
/*!
* \brief Calculate the solution for a linear system of equations
*
* i.e., calculate x, so that it solves Ax = b, where A is a
* tridiagonal matrix.
*/
template <class XVector, class BVector>
void solve(XVector &x, const BVector &b) const
{
if (size() > 2 && diag_[2][0] != 0)
solveWithUpperRight_(x, b);
else
solveWithoutUpperRight_(x, b);
}
/*!
* \brief Print the matrix to a given output stream.
*/
void print(std::ostream &os = std::cout) const
{
int n = size();
// row 0
os << at(0, 0) << "\t"
<< at(0, 1) << "\t";
if (n > 3)
os << "\t";
if (n > 2)
os << at(0, n-1);
os << "\n";
// row 1 .. n - 2
for (int rowIdx = 1; rowIdx < n-1; ++rowIdx) {
if (rowIdx > 1)
os << "\t";
if (rowIdx == n - 2)
os << "\t";
os << at(rowIdx, rowIdx - 1) << "\t"
<< at(rowIdx, rowIdx) << "\t"
<< at(rowIdx, rowIdx + 1) << "\n";
}
// row n - 1
if (n > 2)
os << at(n-1, 0) << "\t";
if (n > 3)
os << "\t";
if (n > 4)
os << "\t";
os << at(n-1, n-2) << "\t"
<< at(n-1, n-1) << "\n";
}
private:
template <class XVector, class BVector>
void solveWithUpperRight_(XVector &x, const BVector &b) const
{
size_t n = size();
std::vector<Scalar> lowerDiag(diag_[0]), mainDiag(diag_[1]), upperDiag(diag_[2]), lastColumn(n);
std::vector<Scalar> bStar(n);
std::copy(b.begin(), b.end(), bStar.begin());
lastColumn[0] = upperDiag[0];
// forward elimination
for (size_t i = 1; i < n; ++i) {
Scalar alpha = lowerDiag[i - 1]/mainDiag[i - 1];
lowerDiag[i - 1] -= alpha * mainDiag[i - 1];
mainDiag[i] -= alpha * upperDiag[i];
bStar[i] -= alpha * bStar[i - 1];
};
// deal with the last row if the entry on the lower left is not zero
if (lowerDiag[n - 1] != 0.0 && size() > 2) {
Scalar lastRow = lowerDiag[n - 1];
for (size_t i = 0; i < n - 1; ++i) {
Scalar alpha = lastRow/mainDiag[i];
lastRow = - alpha*upperDiag[i + 1];
bStar[n - 1] -= alpha * bStar[i];
}
mainDiag[n-1] += lastRow;
}
// backward elimination
x[n - 1] = bStar[n - 1]/mainDiag[n-1];
for (int i = n - 2; i >= 0; --i) {
x[i] = (bStar[i] - x[i + 1]*upperDiag[i+1] - x[n-1]*lastColumn[i])/mainDiag[i];
}
}
template <class XVector, class BVector>
void solveWithoutUpperRight_(XVector &x, const BVector &b) const
{
size_t n = size();
std::vector<Scalar> lowerDiag(diag_[0]), mainDiag(diag_[1]), upperDiag(diag_[2]);
std::vector<Scalar> bStar(n);
std::copy(b.begin(), b.end(), bStar.begin());
// forward elimination
for (size_t i = 1; i < n; ++i) {
Scalar alpha = lowerDiag[i - 1]/mainDiag[i - 1];
lowerDiag[i - 1] -= alpha * mainDiag[i - 1];
mainDiag[i] -= alpha * upperDiag[i];
bStar[i] -= alpha * bStar[i - 1];
};
// deal with the last row if the entry on the lower left is not zero
if (lowerDiag[n - 1] != 0.0 && size() > 2) {
Scalar lastRow = lowerDiag[n - 1];
for (size_t i = 0; i < n - 1; ++i) {
Scalar alpha = lastRow/mainDiag[i];
lastRow = - alpha*upperDiag[i + 1];
bStar[n - 1] -= alpha * bStar[i];
}
mainDiag[n-1] += lastRow;
}
// backward elimination
x[n - 1] = bStar[n - 1]/mainDiag[n-1];
for (int i = n - 2; i >= 0; --i) {
x[i] = (bStar[i] - x[i + 1]*upperDiag[i+1])/mainDiag[i];
}
}
mutable std::vector<Scalar> diag_[3];
};
} // namespace Opm
template <class Scalar>
std::ostream &operator<<(std::ostream &os, const Opm::TridiagonalMatrix<Scalar> &mat)
{
mat.print(os);
return os;
}
#endif