# set_mat Set a single element in the matrix. unsigned char set_mat(lprec *lp, int row, int column, REAL value); Return Value set_mat returns TRUE (1) if the operation was successful. A return value of FALSE (0) indicates an error. Note that row entry mode must be off, else this function also fails. See set_add_rowmode Parameters lp Pointer to previously created lp model. See return value of make_lp, copy_lp, read_lp, read_LP, read_mps, read_freemps, read_MPS, read_freeMPS, read_XLI row Row number of the matrix. Must be between 0 and number of rows in the lp. Row 0 is objective function. column Column number of the matrix. Must be between 1 and number of columns in the lp. value Value to be set for row row, column column. Remarks The set_mat function sets a value in the matrix. If there was already a value for this element, it is replaced and if there was no value, it is added. This function is not efficient if many values are to be set. Consider to use add_constraint, add_constraintex, str_add_constraint, set_row, set_rowex, set_obj_fn, set_obj_fnex, str_set_obj_fn, set_obj, add_column, add_columnex, str_add_column, set_column, set_columnex. Example
    #include <stdio.h>
    #include <stdlib.h>
    #include "lp_lib.h"

    int main(void)
    {
      lprec *lp;

      /* Create a new LP model */
      lp = make_lp(2, 3);
      if(lp == NULL) {
        fprintf(stderr, "Unable to create new LP model\n");
        return(1);
      }

      set_mat(lp, 1, 2, 3.1415927);

      delete_lp(lp);
      return(0);
    }
lp_solve API reference See Also make_lp, copy_lp, read_lp, read_LP, read_mps, read_freemps, read_MPS, read_freeMPS, read_XLI, add_constraint, add_constraintex, str_add_constraint, set_row, set_rowex, set_obj_fn, set_obj_fnex, str_set_obj_fn, add_column, add_columnex, str_add_column, set_column, set_columnex, get_column, get_columnex, get_row, get_rowex, get_mat