The type matrix_t

datatype: matrix_t

A matrix is represented by a structure whose elements prefixed by _ should be considered as private. You access to the element of row i and column j of the matrix matrix_t* mat with the expression mat->p[i][j], whereas the vector (of type vector_t) corresponding to the row i is accessed with mat->p[i]. mat->nbrows and mat->nbcolumns gives you the actual number of rows and columns (the used part), on which ordinary functions operates, but space is allocated for up to mat->_maxrows rows.

For information, it is defined as follows:

typedef struct matrix_t { /* public part */ pkint_t** p; /* array of pointers to rows */ int nbrows; /* number of effective rows */ int nbcolumns; /* size of rows */ /* private part */ pkint_t* _pinit; /* array of coefficients */ int _maxrows; /* number of rows allocated */ bool _sorted; } matrix_t;