static int
partition (int *l, int low, int high)
{
int c;
int middle;
int k = get_pivot (low, high);
int pivot = l[k];
swap (&l[low], &l[k]); // move pivot out of array to order
c = low + 1;
middle = high;
while (c <= middle) // run the array
{
while ((c <= high) && (l[c] <= pivot)) // before pivot
c++;
while ((middle >= low) && (l[middle] > pivot)) // after pivot
middle--;
if (c < middle)
swap (&l[c], &l[middle]);
}
swap (&l[low], &l[middle]); // bring the pivot to its place
return middle;
}
static void handle_sort(t_heap **a_heap, t_heap **b_heap,
t_opt *opt, int *sorted_tab)
{
int nbr_elem_lst;
int i;
i = 1;
nbr_elem_lst = get_nbr_elem(a_heap);
opt->step = get_step(nbr_elem_lst);
while (is_sort(a_heap) != 1)
{
opt->split = get_pivot(sorted_tab, nbr_elem_lst, opt->step, i);
push_step_to_b(opt, nbr_elem_lst, i);
sort_step(a_heap, b_heap, opt);
put_max_in_last_pos(opt);
++i;
}
}
ring_elem DetComputation::bareiss_det()
{
// Computes the determinant of the p by p matrix D. (dense form).
int sign = 1;
size_t pivot_col;
ring_elem pivot = R->from_long(0);
ring_elem lastpivot = R->from_long(0);
for (size_t r=p-1; r>=1; --r)
{
R->remove(lastpivot);
lastpivot = pivot;
if (!get_pivot(D, r, pivot, pivot_col)) // sets pivot_col and pivot
{
// Remove the rest of D.
for (size_t i=0; i<=r; i++)
for (size_t j=0; j<=r; j++)
R->remove(D[i][j]);
R->remove(lastpivot);
return R->from_long(0);
}
for (size_t i=0; i<r; i++)
gauss(D,i,r,pivot_col,lastpivot);
if (((r + pivot_col) % 2) == 1)
sign = -sign; // MES: do I need to rethink this logic?
for (size_t c=0; c<=r; c++)
if (c != pivot_col)
R->remove(D[r][c]);
else
D[r][c] = ZERO_RINGELEM;
}
R->remove(pivot);
R->remove(lastpivot);
ring_elem r = D[0][0];
D[0][0] = ZERO_RINGELEM;
if (sign < 0) R->negate_to(r);
return r;
}
