g2o::MatrixStructure Class Reference

representing the structure of a matrix in column compressed structure (only the upper triangular part of the matrix) More...

#include <matrix_structure.h>

Public Member Functions
	MatrixStructure ()
	~MatrixStructure ()
void	alloc (int n_, int nz)
void	free ()
bool	write (std::string_view filename) const
int	nzMax () const
	max number of non-zeros blocks

Public Attributes
int	n
	A is m-by-n. n must be >= 0.
int	m
	A is m-by-n. m must be >= 0.
int *	Ap
	column pointers for A, of size n+1
int *	Aii
	row indices of A, of size nz = Ap [n]

Protected Attributes
int	maxN
	size of the allocated memory
int	maxNz
	size of the allocated memory

Detailed Description

representing the structure of a matrix in column compressed structure (only the upper triangular part of the matrix)

Definition at line 40 of file matrix_structure.h.

Constructor & Destructor Documentation

MatrixStructure()

g2o::MatrixStructure::MatrixStructure

(

)

Definition at line 45 of file matrix_structure.cpp.

    : n(0), m(0), Ap(0), Aii(0), maxN(0), maxNz(0) {}

~MatrixStructure()

g2o::MatrixStructure::~MatrixStructure

(

)

Definition at line 48 of file matrix_structure.cpp.

{ free(); }

References free().

Member Function Documentation

alloc()

void g2o::MatrixStructure::alloc	(	int	n_,
		int	nz
	)

allocate space for the Matrix Structure. You may call this on an already allocated struct, it will then reallocate the memory + additional space (double the required space).

Definition at line 50 of file matrix_structure.cpp.

                                          {
  if (n == 0) {
    maxN = n = n_;
    maxNz = nz;
    Ap = new int[maxN + 1];
    Aii = new int[maxNz];
  } else {
    n = n_;
    if (maxNz < nz) {
      maxNz = 2 * nz;
      delete[] Aii;
      Aii = new int[maxNz];
    }
    if (maxN < n) {
      maxN = 2 * n;
      delete[] Ap;
      Ap = new int[maxN + 1];
    }
  }
}

References Aii, Ap, maxN, maxNz, and n.

Referenced by g2o::SparseBlockMatrix< MatrixType >::fillBlockStructure().

free()

void g2o::MatrixStructure::free

(

)

Definition at line 71 of file matrix_structure.cpp.

                           {
  n = 0;
  m = 0;
  maxN = 0;
  maxNz = 0;
  delete[] Aii;
  Aii = 0;
  delete[] Ap;
  Ap = 0;
}

References Aii, Ap, m, maxN, maxNz, and n.

Referenced by ~MatrixStructure().

nzMax()

int g2o::MatrixStructure::nzMax ( ) const

inline

max number of non-zeros blocks

Definition at line 65 of file matrix_structure.h.

{ return maxNz; }

Referenced by g2o::LinearSolverCholmod< MatrixType >::computeSymbolicDecomposition(), and g2o::LinearSolverCSparse< MatrixType >::computeSymbolicDecomposition().

write()

bool g2o::MatrixStructure::write

(

std::string_view

filename

)

const

Write the matrix pattern to a file. File is also loadable by octave, e.g., then use spy(matrix)

Definition at line 82 of file matrix_structure.cpp.

                                                         {
  const int& cols = n;
  const int& rows = m;
 
  const string_view name = [&filename]() {
    const std::string::size_type lastDot = filename.find_last_of('.');
    if (lastDot != std::string_view::npos) return filename.substr(0, lastDot);
    return filename;
  }();
 
  vector<pair<int, int> > entries;
  for (int i = 0; i < cols; ++i) {
    const int& rbeg = Ap[i];
    const int& rend = Ap[i + 1];
    for (int j = rbeg; j < rend; ++j) {
      entries.push_back(make_pair(Aii[j], i));
      if (Aii[j] != i) entries.push_back(make_pair(i, Aii[j]));
    }
  }
 
  sort(entries.begin(), entries.end(), ColSort());
 
  const string output_filename(filename);
  std::ofstream fout(output_filename);
  fout << "# name: " << name << std::endl;
  fout << "# type: sparse matrix" << std::endl;
  fout << "# nnz: " << entries.size() << std::endl;
  fout << "# rows: " << rows << std::endl;
  fout << "# columns: " << cols << std::endl;
  for (vector<pair<int, int> >::const_iterator it = entries.begin();
       it != entries.end(); ++it) {
    const pair<int, int>& entry = *it;
    fout << entry.first << " " << entry.second << " 0"
         << std::endl;  // write a constant value of 0
  }
 
  return fout.good();
}

References Aii, Ap, m, and n.

Member Data Documentation

Aii

int* g2o::MatrixStructure::Aii

row indices of A, of size nz = Ap [n]

Definition at line 62 of file matrix_structure.h.

Referenced by alloc(), g2o::LinearSolverCholmodOnline< MatrixType >::computeSymbolicDecomposition(), g2o::LinearSolverCholmod< MatrixType >::computeSymbolicDecomposition(), g2o::LinearSolverCSparse< MatrixType >::computeSymbolicDecomposition(), g2o::SparseBlockMatrix< MatrixType >::fillBlockStructure(), free(), and write().

Ap

int* g2o::MatrixStructure::Ap

column pointers for A, of size n+1

Definition at line 61 of file matrix_structure.h.

Referenced by alloc(), g2o::LinearSolverCholmodOnline< MatrixType >::computeSymbolicDecomposition(), g2o::LinearSolverCholmod< MatrixType >::computeSymbolicDecomposition(), g2o::LinearSolverCSparse< MatrixType >::computeSymbolicDecomposition(), g2o::SparseBlockMatrix< MatrixType >::fillBlockStructure(), free(), and write().

m

int g2o::MatrixStructure::m

A is m-by-n. m must be >= 0.

Definition at line 60 of file matrix_structure.h.

Referenced by g2o::SparseBlockMatrix< MatrixType >::fillBlockStructure(), free(), and write().

maxN

int g2o::MatrixStructure::maxN

protected

size of the allocated memory

Definition at line 68 of file matrix_structure.h.

Referenced by alloc(), and free().

maxNz

int g2o::MatrixStructure::maxNz

protected

size of the allocated memory

Definition at line 69 of file matrix_structure.h.

Referenced by alloc(), and free().

n

int g2o::MatrixStructure::n

A is m-by-n. n must be >= 0.

Definition at line 59 of file matrix_structure.h.

Referenced by alloc(), g2o::LinearSolverCholmodOnline< MatrixType >::computeSymbolicDecomposition(), g2o::LinearSolverCholmod< MatrixType >::computeSymbolicDecomposition(), g2o::LinearSolverCSparse< MatrixType >::computeSymbolicDecomposition(), free(), and write().

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The documentation for this class was generated from the following files:

• /build/reproducible-path/g2o-0~20230806/g2o/core/matrix_structure.h
• /build/reproducible-path/g2o-0~20230806/g2o/core/matrix_structure.cpp