/*
* 主合取范式 或与表达式 大项合取而成
*/
void print_CNF(const int *result, ExpInfo *info)
{
char *letter;
int i, j, count = 0, *a;
/* 永真式没有合取范式 */
if (is_tautology(result, info))
return;
letter = (char *)calloc(info->cols, sizeof(char));
a = (int *)calloc(info->rows, sizeof(int));
/* letter为存放变元的字符数组 */
for (i = j = 0; i < MAX_LETTERS; i++)
{
if (info->elem[i])
letter[j++] = i + 'A';
}
/* a为存放真值表结果中为0的项 */
for (i = 0; i < info->rows; i++)
{
if (result[i] == 0)
a[count++] = i;
}
printf("主合取范式\n");
printf("M(");
for (i = 0; i < count; i++)
{
if (i < count - 1)
printf("%d, ", a[i]);
else
printf("%d", a[i]);
}
printf(")\n");
for (i = 0; i < count; i++)
{
printf("(");
for (j = 0; j < info->cols ; j++)
{
if (test_bit(a[i], info->cols - j - 1))
printf("┐%c", letter[j]);
else
printf("%c", letter[j]);
if (j < info->cols - 1)
printf("∨");
}
if (i < count - 1)
printf(")∧");
else
printf(")\n");
}
free(letter);
free(a);
}
/*
* It turned out to be difficult to cut the branch on which you are sitting
* (i.e. deleting literal_sets from the list we are looping on). I can't think of
* a simple way to implement this.
*/
tv_nf pi_tison(const_tv_nf cf)
{
unsigned int i, q, x, y;
tv_nf result = rdup_tv_nf(cf);
tv_literal_set_list output = get_literal_sets(result);
output = remove_subsumed_literal_set_list(output);
for (i = 0; i < result->variables->sz; i++) {
for (x = 0; x < output->sz; x++) {
tv_literal_set cx = rdup_tv_literal_set(output->arr[x]);
for (y = x + 1; y < output->sz; y++) {
tv_literal_set r = resolve_literal(cx, output->arr[y], i);
if (tv_literal_setNIL != r) {
if (!is_tautology(r)) {
if (is_subsumed_list(output, r)) {
rfre_tv_literal_set(r);
continue;
}
for (q = 0; q < output->sz; q++) {
if (is_subsumed_literal_set(r, output->arr[q])) {
output = delete_tv_literal_set_list(output, q);
if (q <= x) {
x -= 1;
}
if (q <= y) {
y -= 1;
}
q -= 1;
}
}
output = append_tv_literal_set_list(output, r);
} else {
rfre_tv_literal_set(r);
}
}
}
rfre_tv_literal_set(cx);
}
}
set_literal_sets(result, output);
return result;
}
tv_nf pi_brute_force(const_tv_nf cf)
{
unsigned int x, y;
tv_nf copy = rdup_tv_nf(cf); /* We don't want to destroy the input, do we? */
tv_nf result = truncate_copy_nf(cf);
tv_literal_set_list input = get_literal_sets(copy);
tv_literal_set_list output = get_literal_sets(result);
set_literal_sets(copy, (input = remove_subsumed_literal_set_list(input)));
for (x = 0; x < input->sz; x++) {
tv_literal_set cx = input->arr[x];
if (is_subsumed_list(output, cx)) {
continue;
}
output = remove_subsumed_list(output, cx);
for (y = 0; y < output->sz; y++) {
tv_literal_set r = resolve(cx, output->arr[y]);
if (tv_literal_setNIL != r) {
if (!is_tautology(r)) {
input = append_tv_literal_set_list(input, r);
} else {
rfre_tv_literal_set(r);
}
}
}
output = append_tv_literal_set_list(output, rdup_tv_literal_set(cx));
}
rfre_tv_nf(copy);
set_literal_sets(result, output);
return result;
}
