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SparseVector.h
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Sat, Jun 29, 19:11

SparseVector.h
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#ifndef SPARSEVECTOR_H
#define SPARSEVECTOR_H
#include "MatrixLibrary.h"
// No C++ templated typedefs, so use a define, gets cleaned up at end,
// so don't use outside of this class
#define STORE typename std::map<unsigned, T>
/** SparseVector class - an implimentation of a vector that contains a
** majority of zero element, and provides the relevant operations
** specified by the base class Vector.
**/
template<class T>
class SparseVector : public Vector<T> {
//* Multiplies a Matrix by a SparseVector (M*v) and returns a DenseVector.
friend DenseVector<T> operator*<T>(const Matrix<T> &M, const SparseVector<T> &v);
//* Multiplies a SparseVector by a Matrix (M'*v) and returns a DenseVector.
friend DenseVector<T> operator*<T>(const SparseVector<T> &v, const Matrix<T> &M);
//* Computes the dot product between two SparseVectors of equal length.
friend T dot<T>(const SparseVector<T> &a, const SparseVector<T> &b);
//* computes the product of a SparseMatrix tranpose with a SparseVector (M'*v).
friend SparseVector<T> operator*<T>(const SparseMatrix<T> &M, const SparseVector<T> &v);
//* computes the product of a SparseMatrix tranpose with a SparseVector (M'*v).
friend SparseVector<T> operator*<T>(const SparseVector<T> &v, const SparseMatrix<T> &M);
public:
//* Constructor - sets length of vector (NOT # of nonzeros).
SparseVector(unsigned length=0);
//* Copies another SparseVector
SparseVector(const SparseVector<T> &c);
//* Copies a general Vector (avoid if possible, its going to be slow).
SparseVector(const Vector<T> &c);
//* Overrides output to string function to list only nonzeros and indices.
std::string tostring() const;
//* Indexing operators (w/ const overloading).
//@{
T operator()(unsigned i, unsigned j=0) const;
// NOTE reading a non-const SparseVector will call this and add zero entries.
T& operator()(unsigned i, unsigned j=0);
T operator[](unsigned i) const;
T& operator[](unsigned i);
//@}
//* assignment operators
//@{
SparseVector<T>& operator=(SparseVector<T> &c);
SparseVector<T>& operator=(Vector<T> &c);
//@}
//* Return the number of rows in the Vector.
unsigned nRows() const;
//* Returns the number of columns - always 1.
unsigned nCols() const { return 1; }
//* Change # of Vector rows Vector and optionally keeps nonzeros (ignores nCols).
void resize(unsigned nRows, unsigned nCols=1, bool copy=0);
//* Return the number of nonzeros in the Vector.
unsigned size() const;
//* Changes size of Vector rows and optionally removes nonzeros.
void reset (unsigned nRows, unsigned nCols=1, bool zero=0);
//* zeros out all elements while preserving sparcity pattern
void zero();
//* TODO impliment copy (or maybe not necessary)
void copy(const T* ptr, unsigned nRows, unsigned nCols=1);
//* Writes a restart file (TODO impliment this if needed/wanted).
void write_restart(FILE *F) const;
// output to matlab (is this needed)
// using Matrix<T>::matlab;
//* Writes a matlab string to a stream that creates this object with a name.
void matlab(ostream &o, const string &s="v") const;
protected:
//* Banned operators
//@{
SparseVector(const Matrix<T> &c);
SparseVector<T>& operator=(Matrix<T> &c);
T* get_ptr() const {return NULL; }
//@}
STORE data_; //*> sparse data structure
unsigned length_; //*> number of rows
};
#include "SparseVector-inl.h"
#undef STORE
#endif

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