gs_matrix_t *gs_new_matrix(int n_init_rows, int n_init_cols)
{
gs_matrix_t *res = XMALLOCZ(gs_matrix_t);
if (n_init_rows < 16)
n_init_rows = 16;
res->initial_col_increase = n_init_cols;
alloc_rows(res, n_init_rows, n_init_cols, 0);
return res;
}
gs_matrix_t *gs_new_matrix(unsigned n_init_rows, unsigned n_init_cols)
{
gs_matrix_t *res = XMALLOCZ(gs_matrix_t);
alloc_rows(res, n_init_rows, n_init_cols, 0);
return res;
}
void gs_matrix_set(gs_matrix_t *m, int row, int col, double val)
{
row_col_t *the_row;
col_val_t *cols;
int min, max, c, i;
if (row >= m->c_rows) {
int new_c_rows = (int)(ROW_INCREASE_FACTOR * row);
alloc_rows(m, new_c_rows, m->initial_col_increase, m->c_rows);
}
the_row = &m->rows[row];
if (row == col) {
/* Note that we store the diagonal inverted to turn divisions to mults in
* matrix_gauss_seidel(). */
assert(val != 0.0);
the_row->diag = 1.0 / val;
return;
}
// Search for correct column
cols = the_row->cols;
min = 0;
max = the_row->n_cols;
c = max/2;
while (min < max) {
int idx = cols[c].col_idx;
if (idx < col)
min = MAX(c, min+1);
else if (idx > col)
max = MIN(c, max-1);
else
break;
c = (max+min)/2;
}
// Have we found the entry?
if (c < the_row->n_cols && the_row->cols[c].col_idx == col) {
the_row->cols[c].v = val;
if (val == 0.0)
m->n_zero_entries++;
return;
}
// We haven't found the entry, so we must create a new one.
// Is there enough space?
if (the_row->c_cols == the_row->n_cols)
alloc_cols(the_row, the_row->c_cols + COL_INCREASE);
// Shift right-most entries to the right by one
for (i = the_row->n_cols; i > c; --i)
the_row->cols[i] = the_row->cols[i-1];
// Finally insert the new entry
the_row->n_cols++;
the_row->cols[c].col_idx = col;
the_row->cols[c].v = val;
// Check that the entries are sorted
assert(c==0 || the_row->cols[c-1].col_idx < the_row->cols[c].col_idx);
assert(c>=the_row->n_cols-1 || the_row->cols[c].col_idx < the_row->cols[c+1].col_idx);
}
