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aka_csr.hh
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/**
* @file aka_csr.hh
*
* @author Nicolas Richart <nicolas.richart@epfl.ch>
*
* @date creation: Wed Apr 20 2011
* @date last modification: Tue Sep 29 2020
*
* @brief A compresed sparse row structure based on akantu Arrays
*
*
* @section LICENSE
*
* Copyright (©) 2010-2021 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* Akantu is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* Akantu 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 Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "aka_array.hh"
#include "aka_common.hh"
/* -------------------------------------------------------------------------- */
#ifndef AKANTU_AKA_CSR_HH_
#define AKANTU_AKA_CSR_HH_
namespace akantu {
/**
* This class can be used to store the structure of a sparse matrix or for
* vectors with variable number of component per element
*
* @param nb_rows number of rows of a matrix or size of a vector.
*/
template <typename T> class CSR {
/* ------------------------------------------------------------------------ */
/* Constructors/Destructors */
/* ------------------------------------------------------------------------ */
public:
explicit CSR(UInt nb_rows = 0)
: nb_rows(nb_rows), rows_offsets(nb_rows + 1, 1, "rows_offsets"),
rows(0, 1, "rows") {
rows_offsets.zero();
};
virtual ~CSR() = default;
/* ------------------------------------------------------------------------ */
/* Methods */
/* ------------------------------------------------------------------------ */
public:
/// does nothing
inline void beginInsertions(){};
/// insert a new entry val in row row
inline UInt insertInRow(UInt row, const T & val) {
UInt pos = rows_offsets(row)++;
rows(pos) = val;
return pos;
}
/// access an element of the matrix
inline const T & operator()(UInt row, UInt col) const {
AKANTU_DEBUG_ASSERT(rows_offsets(row + 1) - rows_offsets(row) > col,
"This element is not present in this CSR");
return rows(rows_offsets(row) + col);
}
/// access an element of the matrix
inline T & operator()(UInt row, UInt col) {
AKANTU_DEBUG_ASSERT(rows_offsets(row + 1) - rows_offsets(row) > col,
"This element is not present in this CSR");
return rows(rows_offsets(row) + col);
}
inline void endInsertions() {
for (UInt i = nb_rows; i > 0; --i) {
rows_offsets(i) = rows_offsets(i - 1);
}
rows_offsets(0) = 0;
}
inline void countToCSR() {
for (UInt i = 1; i < nb_rows; ++i) {
rows_offsets(i) += rows_offsets(i - 1);
}
for (UInt i = nb_rows; i >= 1; --i) {
rows_offsets(i) = rows_offsets(i - 1);
}
rows_offsets(0) = 0;
}
inline void clearRows() {
rows_offsets.zero();
rows.resize(0);
};
inline void resizeRows(UInt nb_rows) {
this->nb_rows = nb_rows;
rows_offsets.resize(nb_rows + 1);
rows_offsets.zero();
}
inline void resizeCols() { rows.resize(rows_offsets(nb_rows)); }
inline void copy(Array<UInt> & offsets, Array<T> & values) {
offsets.copy(rows_offsets);
values.copy(rows);
}
/* ------------------------------------------------------------------------ */
/* Accessors */
/* ------------------------------------------------------------------------ */
public:
/// returns the number of rows
inline UInt getNbRows() const { return rows_offsets.size() - 1; };
/// returns the number of non-empty columns in a given row
inline UInt getNbCols(UInt row) const {
return rows_offsets(row + 1) - rows_offsets(row);
};
/// returns the offset (start of columns) for a given row
inline UInt & rowOffset(UInt row) { return rows_offsets(row); };
// /// iterator on a row
// template <class array_iterator>
// class iterator_internal
// : public std::iterator<std::bidirectional_iterator_tag, typename
// array_iterator::value_type> {
// public:
// using _parent = std::iterator<std::bidirectional_iterator_tag, R>;
// using pointer = typename _parent::pointer;
// using reference = typename _parent::reference;
// explicit iterator_internal(array_iterator ait) : pos(std::move(ait)){};
// iterator_internal(const iterator_internal & it) : pos(it.pos){};
// iterator_internal & operator++() {
// ++pos;
// return *this;
// };
// iterator_internal operator++(int) {
// iterator tmp(*this);
// operator++();
// return tmp;
// };
// iterator_internal & operator--() {
// --pos;
// return *this;
// };
// iterator_internal operator--(int) {
// iterator_internal tmp(*this);
// operator--();
// return tmp;
// };
// bool operator==(const iterator_internal & rhs) { return pos == rhs.pos;
// }; bool operator!=(const iterator_internal & rhs) { return pos !=
// rhs.pos; }; reference operator*() { return *pos; }; pointer operator->()
// const { return pos; };
// private:
// array_iterator pos;
// };
using iterator = typename Array<T>::scalar_iterator;
using const_iterator = typename Array<T>::const_scalar_iterator;
template <typename iterator_internal> class CSRRow {
public:
CSRRow(iterator_internal begin, iterator_internal end)
: begin_(std::move(begin)), end_(std::move(end)) {}
inline auto begin() const { return begin_; }
inline auto end() const { return end_; }
private:
iterator_internal begin_, end_;
};
inline iterator begin(UInt row) { return rows.begin() + rows_offsets(row); };
inline iterator end(UInt row) {
return rows.begin() + rows_offsets(row + 1);
};
inline const_iterator begin(UInt row) const {
return rows.begin() + rows_offsets(row);
};
inline const_iterator end(UInt row) const {
return rows.begin() + rows_offsets(row + 1);
};
private:
template <typename iterator_internal>
decltype(auto) make_row(iterator_internal begin, iterator_internal end) {
return CSRRow<iterator_internal>(std::move(begin), std::move(end));
}
public:
inline decltype(auto) getRow(UInt row) {
return make_row(begin(row), end(row));
}
inline decltype(auto) getRow(UInt row) const {
return make_row(begin(row), end(row));
}
inline iterator rbegin(UInt row) {
return rows.begin() + rows_offsets(row + 1) - 1;
};
inline iterator rend(UInt row) {
return rows.begin() + rows_offsets(row) - 1;
};
inline const Array<UInt> & getRowsOffset() const { return rows_offsets; };
inline const Array<T> & getRows() const { return rows; };
inline Array<T> & getRows() { return rows; };
/* ------------------------------------------------------------------------ */
/* Class Members */
/* ------------------------------------------------------------------------ */
protected:
UInt nb_rows;
/// array of size nb_rows containing the offset where the values are stored in
Array<UInt> rows_offsets;
/// compressed row values, values of row[i] are stored between rows_offsets[i]
/// and rows_offsets[i+1]
Array<T> rows;
};
/* -------------------------------------------------------------------------- */
/* Data CSR */
/* -------------------------------------------------------------------------- */
/**
* Inherits from CSR<UInt> and can contain information such as matrix values
* where the mother class would be a CSR structure for row and cols
*
* @return nb_rows
*/
template <class T> class DataCSR : public CSR<UInt> {
public:
DataCSR(UInt nb_rows = 0) : CSR<UInt>(nb_rows), data(0, 1){};
inline void resizeCols() {
CSR<UInt>::resizeCols();
data.resize(rows_offsets(nb_rows));
}
inline const Array<T> & getData() const { return data; };
private:
Array<T> data;
};
/* -------------------------------------------------------------------------- */
/* inline functions */
/* -------------------------------------------------------------------------- */
//#include "aka_csr_inline_impl.hh"
/// standard output stream operator
// inline std::ostream & operator <<(std::ostream & stream, const CSR & _this)
// {
// _this.printself(stream);
// return stream;
// }
} // namespace akantu
#endif /* AKANTU_AKA_CSR_HH_ */

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