// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_COMPRESSED_STORAGE_H
#define EIGEN_COMPRESSED_STORAGE_H
namespace Eigen {
namespace internal {
/** \internal
* Stores a sparse set of values as a list of values and a list of indices.
*
*/
template<typename _Scalar,typename _Index>
class CompressedStorage
{
public:
typedef _Scalar Scalar;
typedef _Index Index;
protected:
typedef typename NumTraits<Scalar>::Real RealScalar;
public:
CompressedStorage()
: m_values(0), m_indices(0), m_size(0), m_allocatedSize(0)
{}
CompressedStorage(size_t size)
: m_values(0), m_indices(0), m_size(0), m_allocatedSize(0)
{
resize(size);
}
CompressedStorage(const CompressedStorage& other)
: m_values(0), m_indices(0), m_size(0), m_allocatedSize(0)
{
*this = other;
}
CompressedStorage& operator=(const CompressedStorage& other)
{
resize(other.size());
memcpy(m_values, other.m_values, m_size * sizeof(Scalar));
memcpy(m_indices, other.m_indices, m_size * sizeof(Index));
return *this;
}
void swap(CompressedStorage& other)
{
std::swap(m_values, other.m_values);
std::swap(m_indices, other.m_indices);
std::swap(m_size, other.m_size);
std::swap(m_allocatedSize, other.m_allocatedSize);
}
~CompressedStorage()
{
delete[] m_values;
delete[] m_indices;
}
void reserve(size_t size)
{
size_t newAllocatedSize = m_size + size;
if (newAllocatedSize > m_allocatedSize)
reallocate(newAllocatedSize);
}
void squeeze()
{
if (m_allocatedSize>m_size)
reallocate(m_size);
}
void resize(size_t size, float reserveSizeFactor = 0)
{
if (m_allocatedSize<size)
reallocate(size + size_t(reserveSizeFactor*size));
m_size = size;
}
void append(const Scalar& v, Index i)
{
Index id = static_cast<Index>(m_size);
resize(m_size+1, 1);
m_values[id] = v;
m_indices[id] = i;
}
inline size_t size() const { return m_size; }
inline size_t allocatedSize() const { return m_allocatedSize; }
inline void clear() { m_size = 0; }
inline Scalar& value(size_t i) { return m_values[i]; }
inline const Scalar& value(size_t i) const { return m_values[i]; }
inline Index& index(size_t i) { return m_indices[i]; }
inline const Index& index(size_t i) const { return m_indices[i]; }
static CompressedStorage Map(Index* indices, Scalar* values, size_t size)
{
CompressedStorage res;
res.m_indices = indices;
res.m_values = values;
res.m_allocatedSize = res.m_size = size;
return res;
}
/** \returns the largest \c k such that for all \c j in [0,k) index[\c j]\<\a key */
inline Index searchLowerIndex(Index key) const
{
return searchLowerIndex(0, m_size, key);
}
/** \returns the largest \c k in [start,end) such that for all \c j in [start,k) index[\c j]\<\a key */
inline Index searchLowerIndex(size_t start, size_t end, Index key) const
{
while(end>start)
{
size_t mid = (end+start)>>1;
if (m_indices[mid]<key)
start = mid+1;
else
end = mid;
}
return static_cast<Index>(start);
}
/** \returns the stored value at index \a key
* If the value does not exist, then the value \a defaultValue is returned without any insertion. */
inline Scalar at(Index key, Scalar defaultValue = Scalar(0)) const
{
if (m_size==0)
return defaultValue;
else if (key==m_indices[m_size-1])
return m_values[m_size-1];
// ^^ optimization: let's first check if it is the last coefficient
// (very common in high level algorithms)
const size_t id = searchLowerIndex(0,m_size-1,key);
return ((id<m_size) && (m_indices[id]==key)) ? m_values[id] : defaultValue;
}
/** Like at(), but the search is performed in the range [start,end) */
inline Scalar atInRange(size_t start, size_t end, Index key, Scalar defaultValue = Scalar(0)) const
{
if (start>=end)
return Scalar(0);
else if (end>start && key==m_indices[end-1])
return m_values[end-1];
// ^^ optimization: let's first check if it is the last coefficient
// (very common in high level algorithms)
const size_t id = searchLowerIndex(start,end-1,key);
return ((id<end) && (m_indices[id]==key)) ? m_values[id] : defaultValue;
}
/** \returns a reference to the value at index \a key
* If the value does not exist, then the value \a defaultValue is inserted
* such that the keys are sorted. */
inline Scalar& atWithInsertion(Index key, Scalar defaultValue = Scalar(0))
{
size_t id = searchLowerIndex(0,m_size,key);
if (id>=m_size || m_indices[id]!=key)
{
resize(m_size+1,1);
for (size_t j=m_size-1; j>id; --j)
{
m_indices[j] = m_indices[j-1];
m_values[j] = m_values[j-1];
}
m_indices[id] = key;
m_values[id] = defaultValue;
}
return m_values[id];
}
void prune(Scalar reference, RealScalar epsilon = NumTraits<RealScalar>::dummy_precision())
{
size_t k = 0;
size_t n = size();
for (size_t i=0; i<n; ++i)
{
if (!internal::isMuchSmallerThan(value(i), reference, epsilon))
{
value(k) = value(i);
index(k) = index(i);
++k;
}
}
resize(k,0);
}
protected:
inline void reallocate(size_t size)
{
Scalar* newValues = new Scalar[size];
Index* newIndices = new Index[size];
size_t copySize = (std::min)(size, m_size);
// copy
internal::smart_copy(m_values, m_values+copySize, newValues);
internal::smart_copy(m_indices, m_indices+copySize, newIndices);
// delete old stuff
delete[] m_values;
delete[] m_indices;
m_values = newValues;
m_indices = newIndices;
m_allocatedSize = size;
}
protected:
Scalar* m_values;
Index* m_indices;
size_t m_size;
size_t m_allocatedSize;
};
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_COMPRESSED_STORAGE_H