C++ implements a compressed storage instance of a sparse matrix

C++ implements compressed storage instances of sparse matrices

Sparse matrix: the matrix of M*N, the number of valid values in the matrix is much smaller than the number of invalid values, and the distribution of these data is irregular.

Compressed storage of sparse matrices: compressed stored values store very little valid data. Use {row,col,value}3 tuples to store each valid data. The 3 tuples are stored in the order of row priority according to the position in the original matrix.

Implementation code:

#include <iostream> 
#include <vector> 
using namespace std; 
 
template<class T> 
struct Triple    //3 tuples  
{ 
  size_t _row;  // line  
  size_t _col;  // column  
  T _value;  // value  
 
  Triple(size_t row, size_t col, const T& value) 
    :_row(row) 
    , _col(col) 
    , _value(value) 
  {} 
}; 
 
 
template<class T> 
class SparseMatrix   // Sparse matrix  
{ 
protected: 
  vector<Triple<T>> _matrix; // The compression matrix of dynamic capacity increase can be realized  
  size_t _m;  // line  
  size_t _n;  // column  
  T _invalid;   // The default value  
 
public: 
  SparseMatrix(T* a, size_t m, size_t n, const T& invalid= T()) 
    :_m(m) 
    , _n(n) 
    , _invalid(invalid) 
  { 
    for (size_t i = 0; i < m; ++i) 
    { 
      for (size_t j = 0; j < n; ++j) 
      { 
        Triple<T> t(i, j, a[i*n + j]); 
        _matrix.push_back(t); 
      } 
    } 
  } 
 
  void Display() 
  { 
    size_t index = 0; 
    for (size_t i = 0; i < _m; ++i) 
    { 
      for (size_t j = 0; j < _n; ++j) 
      { 
        if (index < _matrix.size() 
          && _matrix[index]._row== i 
          &&_matrix[index]._col ==j) 
        { 
          cout << _matrix[index]._value << " "; 
          ++index; 
        } 
        else 
        { 
          cout << _invalid << " "; 
        } 
      } 
      cout << endl; 
    } 
    cout << endl; 
  } 
 
 
 
}; 

#include <windows.h> 
 
void test() 
{ 
  int a[6][5] = 
  { 
    { 1, 0, 2, 0, 0 }, 
    { 1, 0, 1, 0, 3 }, 
    { 2, 0, 0, 1, 2 }, 
    { 3, 0, 1, 0, 0 }, 
    { 4, 0, 2, 0, 0 }, 
    { 0, 3, 4, 0, 0 }, 
  }; 
 
  SparseMatrix<int> sm((int*)a, 6, 5, 0); 
  //SymmetricMatrix(int a[][N], size_t N) 
  sm.Display(); 
 
} 
 
 
int main() 
{ 
  test(); 
 
  system("pause"); 
  return 0; 
} 

Above is the sparse matrix of compressed storage of the case details, if you have any questions please leave a message or to the site community exchange discussion, thank you for reading, hope to help you, thank you for the support of the site!