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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
//
// Eigen 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.
//
// Alternatively, 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.
//
// Eigen 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 or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.
#ifndef EIGEN_RANDOMSETTER_H
#define EIGEN_RANDOMSETTER_H
template<typename Scalar> struct StdMapTraits
{
typedef int KeyType;
typedef std::map<KeyType,Scalar> Type;
enum {
IsSorted = 1
};
static void setInvalidKey(Type&, const KeyType&) {}
};
#ifdef _HASH_MAP
template<typename Scalar> struct GnuHashMapTraits
{
typedef int KeyType;
typedef __gnu_cxx::hash_map<KeyType,Scalar> Type;
enum {
IsSorted = 0
};
static void setInvalidKey(Type&, const KeyType&) {}
};
#endif
#ifdef _DENSE_HASH_MAP_H_
template<typename Scalar> struct GoogleDenseHashMapTraits
{
typedef int KeyType;
typedef google::dense_hash_map<KeyType,Scalar> Type;
enum {
IsSorted = 0
};
static void setInvalidKey(Type& map, const KeyType& k)
{ map.set_empty_key(k); }
};
#endif
#ifdef _SPARSE_HASH_MAP_H_
template<typename Scalar> struct GoogleSparseHashMapTraits
{
typedef int KeyType;
typedef google::sparse_hash_map<KeyType,Scalar> Type;
enum {
IsSorted = 0
};
static void setInvalidKey(Type&, const KeyType&) {}
};
#endif
/** \class RandomSetter
*
* Typical usage:
* \code
* SparseMatrix<double> m(rows,cols);
* {
* RandomSetter<SparseMatrix<double> > w(m);
* // don't use m but w instead with read/write random access to the coefficients:
* for(;;)
* w(rand(),rand()) = rand;
* }
* // when w is deleted, the data are copied back to m
* // and m is ready to use.
* \endcode
*
* \note for performance and memory consumption reasons it is highly recommended to use
* Google's hash library. To do so you have two options:
* - include <google/dense_hash_map> yourself \b before Eigen/Sparse header
* - define EIGEN_GOOGLEHASH_SUPPORT
* In the later case the inclusion of <google/dense_hash_map> is made for you.
*/
template<typename SparseMatrixType,
template <typename T> class MapTraits =
#if defined _DENSE_HASH_MAP_H_
GoogleDenseHashMapTraits
#elif defined _HASH_MAP
GnuHashMapTraits
#else
StdMapTraits
#endif
,int OuterPacketBits = 6>
class RandomSetter
{
typedef typename ei_traits<SparseMatrixType>::Scalar Scalar;
struct ScalarWrapper
{
ScalarWrapper() : value(0) {}
Scalar value;
};
typedef typename MapTraits<ScalarWrapper>::KeyType KeyType;
typedef typename MapTraits<ScalarWrapper>::Type HashMapType;
static const int OuterPacketMask = (1 << OuterPacketBits) - 1;
enum {
SwapStorage = 1 - MapTraits<ScalarWrapper>::IsSorted,
TargetRowMajor = (SparseMatrixType::Flags & RowMajorBit) ? 1 : 0,
SetterRowMajor = SwapStorage ? 1-TargetRowMajor : TargetRowMajor
};
public:
inline RandomSetter(SparseMatrixType& target)
: mp_target(&target)
{
const int outerSize = SwapStorage ? target.innerSize() : target.outerSize();
const int innerSize = SwapStorage ? target.outerSize() : target.innerSize();
m_outerPackets = outerSize >> OuterPacketBits;
if (outerSize&OuterPacketMask)
m_outerPackets += 1;
m_hashmaps = new HashMapType[m_outerPackets];
// compute number of bits needed to store inner indices
int aux = innerSize - 1;
m_keyBitsOffset = 0;
while (aux)
{
++m_keyBitsOffset;
aux = aux >> 1;
}
KeyType ik = (1<<(OuterPacketBits+m_keyBitsOffset));
for (int k=0; k<m_outerPackets; ++k)
MapTraits<ScalarWrapper>::setInvalidKey(m_hashmaps[k],ik);
// insert current coeffs
for (int j=0; j<mp_target->outerSize(); ++j)
for (typename SparseMatrixType::InnerIterator it(*mp_target,j); it; ++it)
(*this)(TargetRowMajor?j:it.index(), TargetRowMajor?it.index():j) = it.value();
}
~RandomSetter()
{
KeyType keyBitsMask = (1<<m_keyBitsOffset)-1;
if (!SwapStorage) // also means the map is sorted
{
mp_target->startFill(nonZeros());
for (int k=0; k<m_outerPackets; ++k)
{
const int outerOffset = (1<<OuterPacketBits) * k;
typename HashMapType::iterator end = m_hashmaps[k].end();
for (typename HashMapType::iterator it = m_hashmaps[k].begin(); it!=end; ++it)
{
const int outer = (it->first >> m_keyBitsOffset) + outerOffset;
const int inner = it->first & keyBitsMask;
mp_target->fill(TargetRowMajor ? outer : inner, TargetRowMajor ? inner : outer) = it->second.value;
}
}
mp_target->endFill();
}
else
{
VectorXi positions(mp_target->outerSize());
positions.setZero();
// pass 1
for (int k=0; k<m_outerPackets; ++k)
{
typename HashMapType::iterator end = m_hashmaps[k].end();
for (typename HashMapType::iterator it = m_hashmaps[k].begin(); it!=end; ++it)
{
const int outer = it->first & keyBitsMask;
++positions[outer];
}
}
// prefix sum
int count = 0;
for (int j=0; j<mp_target->outerSize(); ++j)
{
int tmp = positions[j];
mp_target->_outerIndexPtr()[j] = count;
positions[j] = count;
count += tmp;
}
mp_target->_outerIndexPtr()[mp_target->outerSize()] = count;
mp_target->resizeNonZeros(count);
// pass 2
for (int k=0; k<m_outerPackets; ++k)
{
const int outerOffset = (1<<OuterPacketBits) * k;
typename HashMapType::iterator end = m_hashmaps[k].end();
for (typename HashMapType::iterator it = m_hashmaps[k].begin(); it!=end; ++it)
{
const int inner = (it->first >> m_keyBitsOffset) + outerOffset;
const int outer = it->first & keyBitsMask;
// sorted insertion
// Note that we have to deal with at most 2^OuterPacketBits unsorted coefficients,
// moreover those 2^OuterPacketBits coeffs are likely to be sparse, an so only a
// small fraction of them have to be sorted, whence the following simple procedure:
int posStart = mp_target->_outerIndexPtr()[outer];
int i = (positions[outer]++) - 1;
while ( (i >= posStart) && (mp_target->_innerIndexPtr()[i] > inner) )
{
mp_target->_valuePtr()[i+1] = mp_target->_valuePtr()[i];
mp_target->_innerIndexPtr()[i+1] = mp_target->_innerIndexPtr()[i];
--i;
}
mp_target->_innerIndexPtr()[i+1] = inner;
mp_target->_valuePtr()[i+1] = it->second.value;
}
}
}
delete[] m_hashmaps;
}
Scalar& operator() (int row, int col)
{
const int outer = SetterRowMajor ? row : col;
const int inner = SetterRowMajor ? col : row;
const int outerMajor = outer >> OuterPacketBits; // index of the packet/map
const int outerMinor = outer & OuterPacketMask; // index of the inner vector in the packet
const KeyType key = (KeyType(outerMinor)<<m_keyBitsOffset) | inner;
return m_hashmaps[outerMajor][key].value;
}
// might be slow
int nonZeros() const
{
int nz = 0;
for (int k=0; k<m_outerPackets; ++k)
nz += m_hashmaps[k].size();
return nz;
}
protected:
HashMapType* m_hashmaps;
SparseMatrixType* mp_target;
int m_outerPackets;
unsigned char m_keyBitsOffset;
};
#endif // EIGEN_RANDOMSETTER_H