1/*
2 * Copyright 2008-2009 Katholieke Universiteit Leuven
3 * Copyright 2010      INRIA Saclay
4 * Copyright 2014      Ecole Normale Superieure
5 * Copyright 2017      Sven Verdoolaege
6 *
7 * Use of this software is governed by the MIT license
8 *
9 * Written by Sven Verdoolaege, K.U.Leuven, Departement
10 * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
11 * and INRIA Saclay - Ile-de-France, Parc Club Orsay Universite,
12 * ZAC des vignes, 4 rue Jacques Monod, 91893 Orsay, France
13 * and Ecole Normale Superieure, 45 rue d'Ulm, 75230 Paris, France
14 */
15
16#include <isl_ctx_private.h>
17#include <isl_map_private.h>
18#include <isl/space.h>
19#include <isl_seq.h>
20#include <isl_mat_private.h>
21#include <isl_vec_private.h>
22#include <isl_space_private.h>
23#include <isl_val_private.h>
24
25isl_ctx *isl_mat_get_ctx(__isl_keep isl_mat *mat)
26{
27	return mat ? mat->ctx : NULL;
28}
29
30/* Return a hash value that digests "mat".
31 */
32uint32_t isl_mat_get_hash(__isl_keep isl_mat *mat)
33{
34	int i;
35	uint32_t hash;
36
37	if (!mat)
38		return 0;
39
40	hash = isl_hash_init();
41	isl_hash_byte(hash, mat->n_row & 0xFF);
42	isl_hash_byte(hash, mat->n_col & 0xFF);
43	for (i = 0; i < mat->n_row; ++i) {
44		uint32_t row_hash;
45
46		row_hash = isl_seq_get_hash(mat->row[i], mat->n_col);
47		isl_hash_hash(hash, row_hash);
48	}
49
50	return hash;
51}
52
53__isl_give isl_mat *isl_mat_alloc(isl_ctx *ctx,
54	unsigned n_row, unsigned n_col)
55{
56	int i;
57	struct isl_mat *mat;
58
59	mat = isl_alloc_type(ctx, struct isl_mat);
60	if (!mat)
61		return NULL;
62
63	mat->row = NULL;
64	mat->block = isl_blk_alloc(ctx, n_row * n_col);
65	if (isl_blk_is_error(mat->block))
66		goto error;
67	mat->row = isl_calloc_array(ctx, isl_int *, n_row);
68	if (n_row && !mat->row)
69		goto error;
70
71	if (n_col != 0) {
72		for (i = 0; i < n_row; ++i)
73			mat->row[i] = mat->block.data + i * n_col;
74	}
75
76	mat->ctx = ctx;
77	isl_ctx_ref(ctx);
78	mat->ref = 1;
79	mat->n_row = n_row;
80	mat->n_col = n_col;
81	mat->max_col = n_col;
82	mat->flags = 0;
83
84	return mat;
85error:
86	isl_blk_free(ctx, mat->block);
87	free(mat);
88	return NULL;
89}
90
91__isl_give isl_mat *isl_mat_extend(__isl_take isl_mat *mat,
92	unsigned n_row, unsigned n_col)
93{
94	int i;
95	isl_int *old;
96	isl_int **row;
97
98	if (!mat)
99		return NULL;
100
101	if (mat->max_col >= n_col && mat->n_row >= n_row) {
102		if (mat->n_col < n_col)
103			mat->n_col = n_col;
104		return mat;
105	}
106
107	if (mat->max_col < n_col) {
108		struct isl_mat *new_mat;
109
110		if (n_row < mat->n_row)
111			n_row = mat->n_row;
112		new_mat = isl_mat_alloc(mat->ctx, n_row, n_col);
113		if (!new_mat)
114			goto error;
115		for (i = 0; i < mat->n_row; ++i)
116			isl_seq_cpy(new_mat->row[i], mat->row[i], mat->n_col);
117		isl_mat_free(mat);
118		return new_mat;
119	}
120
121	mat = isl_mat_cow(mat);
122	if (!mat)
123		goto error;
124
125	old = mat->block.data;
126	mat->block = isl_blk_extend(mat->ctx, mat->block, n_row * mat->max_col);
127	if (isl_blk_is_error(mat->block))
128		goto error;
129	row = isl_realloc_array(mat->ctx, mat->row, isl_int *, n_row);
130	if (n_row && !row)
131		goto error;
132	mat->row = row;
133
134	for (i = 0; i < mat->n_row; ++i)
135		mat->row[i] = mat->block.data + (mat->row[i] - old);
136	for (i = mat->n_row; i < n_row; ++i)
137		mat->row[i] = mat->block.data + i * mat->max_col;
138	mat->n_row = n_row;
139	if (mat->n_col < n_col)
140		mat->n_col = n_col;
141
142	return mat;
143error:
144	isl_mat_free(mat);
145	return NULL;
146}
147
148__isl_give isl_mat *isl_mat_sub_alloc6(isl_ctx *ctx, isl_int **row,
149	unsigned first_row, unsigned n_row, unsigned first_col, unsigned n_col)
150{
151	int i;
152	struct isl_mat *mat;
153
154	mat = isl_alloc_type(ctx, struct isl_mat);
155	if (!mat)
156		return NULL;
157	mat->row = isl_alloc_array(ctx, isl_int *, n_row);
158	if (n_row && !mat->row)
159		goto error;
160	for (i = 0; i < n_row; ++i)
161		mat->row[i] = row[first_row+i] + first_col;
162	mat->ctx = ctx;
163	isl_ctx_ref(ctx);
164	mat->ref = 1;
165	mat->n_row = n_row;
166	mat->n_col = n_col;
167	mat->block = isl_blk_empty();
168	mat->flags = ISL_MAT_BORROWED;
169	return mat;
170error:
171	free(mat);
172	return NULL;
173}
174
175__isl_give isl_mat *isl_mat_sub_alloc(__isl_keep isl_mat *mat,
176	unsigned first_row, unsigned n_row, unsigned first_col, unsigned n_col)
177{
178	if (!mat)
179		return NULL;
180	return isl_mat_sub_alloc6(mat->ctx, mat->row, first_row, n_row,
181				  first_col, n_col);
182}
183
184void isl_mat_sub_copy(struct isl_ctx *ctx, isl_int **dst, isl_int **src,
185	unsigned n_row, unsigned dst_col, unsigned src_col, unsigned n_col)
186{
187	int i;
188
189	for (i = 0; i < n_row; ++i)
190		isl_seq_cpy(dst[i]+dst_col, src[i]+src_col, n_col);
191}
192
193void isl_mat_sub_neg(struct isl_ctx *ctx, isl_int **dst, isl_int **src,
194	unsigned n_row, unsigned dst_col, unsigned src_col, unsigned n_col)
195{
196	int i;
197
198	for (i = 0; i < n_row; ++i)
199		isl_seq_neg(dst[i]+dst_col, src[i]+src_col, n_col);
200}
201
202__isl_give isl_mat *isl_mat_copy(__isl_keep isl_mat *mat)
203{
204	if (!mat)
205		return NULL;
206
207	mat->ref++;
208	return mat;
209}
210
211__isl_give isl_mat *isl_mat_dup(__isl_keep isl_mat *mat)
212{
213	int i;
214	struct isl_mat *mat2;
215
216	if (!mat)
217		return NULL;
218	mat2 = isl_mat_alloc(mat->ctx, mat->n_row, mat->n_col);
219	if (!mat2)
220		return NULL;
221	for (i = 0; i < mat->n_row; ++i)
222		isl_seq_cpy(mat2->row[i], mat->row[i], mat->n_col);
223	return mat2;
224}
225
226__isl_give isl_mat *isl_mat_cow(__isl_take isl_mat *mat)
227{
228	struct isl_mat *mat2;
229	if (!mat)
230		return NULL;
231
232	if (mat->ref == 1 && !ISL_F_ISSET(mat, ISL_MAT_BORROWED))
233		return mat;
234
235	mat2 = isl_mat_dup(mat);
236	isl_mat_free(mat);
237	return mat2;
238}
239
240__isl_null isl_mat *isl_mat_free(__isl_take isl_mat *mat)
241{
242	if (!mat)
243		return NULL;
244
245	if (--mat->ref > 0)
246		return NULL;
247
248	if (!ISL_F_ISSET(mat, ISL_MAT_BORROWED))
249		isl_blk_free(mat->ctx, mat->block);
250	isl_ctx_deref(mat->ctx);
251	free(mat->row);
252	free(mat);
253
254	return NULL;
255}
256
257isl_size isl_mat_rows(__isl_keep isl_mat *mat)
258{
259	return mat ? mat->n_row : isl_size_error;
260}
261
262isl_size isl_mat_cols(__isl_keep isl_mat *mat)
263{
264	return mat ? mat->n_col : isl_size_error;
265}
266
267/* Check that "col" is a valid column position for "mat".
268 */
269static isl_stat check_col(__isl_keep isl_mat *mat, int col)
270{
271	if (!mat)
272		return isl_stat_error;
273	if (col < 0 || col >= mat->n_col)
274		isl_die(isl_mat_get_ctx(mat), isl_error_invalid,
275			"column out of range", return isl_stat_error);
276	return isl_stat_ok;
277}
278
279/* Check that "row" is a valid row position for "mat".
280 */
281static isl_stat check_row(__isl_keep isl_mat *mat, int row)
282{
283	if (!mat)
284		return isl_stat_error;
285	if (row < 0 || row >= mat->n_row)
286		isl_die(isl_mat_get_ctx(mat), isl_error_invalid,
287			"row out of range", return isl_stat_error);
288	return isl_stat_ok;
289}
290
291/* Check that there are "n" columns starting at position "first" in "mat".
292 */
293static isl_stat check_col_range(__isl_keep isl_mat *mat, unsigned first,
294	unsigned n)
295{
296	if (!mat)
297		return isl_stat_error;
298	if (first + n > mat->n_col || first + n < first)
299		isl_die(isl_mat_get_ctx(mat), isl_error_invalid,
300			"column position or range out of bounds",
301			return isl_stat_error);
302	return isl_stat_ok;
303}
304
305/* Check that there are "n" rows starting at position "first" in "mat".
306 */
307static isl_stat check_row_range(__isl_keep isl_mat *mat, unsigned first,
308	unsigned n)
309{
310	if (!mat)
311		return isl_stat_error;
312	if (first + n > mat->n_row || first + n < first)
313		isl_die(isl_mat_get_ctx(mat), isl_error_invalid,
314			"row position or range out of bounds",
315			return isl_stat_error);
316	return isl_stat_ok;
317}
318
319int isl_mat_get_element(__isl_keep isl_mat *mat, int row, int col, isl_int *v)
320{
321	if (check_row(mat, row) < 0)
322		return -1;
323	if (check_col(mat, col) < 0)
324		return -1;
325	isl_int_set(*v, mat->row[row][col]);
326	return 0;
327}
328
329/* Extract the element at row "row", oolumn "col" of "mat".
330 */
331__isl_give isl_val *isl_mat_get_element_val(__isl_keep isl_mat *mat,
332	int row, int col)
333{
334	isl_ctx *ctx;
335
336	if (check_row(mat, row) < 0)
337		return NULL;
338	if (check_col(mat, col) < 0)
339		return NULL;
340	ctx = isl_mat_get_ctx(mat);
341	return isl_val_int_from_isl_int(ctx, mat->row[row][col]);
342}
343
344__isl_give isl_mat *isl_mat_set_element(__isl_take isl_mat *mat,
345	int row, int col, isl_int v)
346{
347	mat = isl_mat_cow(mat);
348	if (check_row(mat, row) < 0)
349		return isl_mat_free(mat);
350	if (check_col(mat, col) < 0)
351		return isl_mat_free(mat);
352	isl_int_set(mat->row[row][col], v);
353	return mat;
354}
355
356__isl_give isl_mat *isl_mat_set_element_si(__isl_take isl_mat *mat,
357	int row, int col, int v)
358{
359	mat = isl_mat_cow(mat);
360	if (check_row(mat, row) < 0)
361		return isl_mat_free(mat);
362	if (check_col(mat, col) < 0)
363		return isl_mat_free(mat);
364	isl_int_set_si(mat->row[row][col], v);
365	return mat;
366}
367
368/* Replace the element at row "row", column "col" of "mat" by "v".
369 */
370__isl_give isl_mat *isl_mat_set_element_val(__isl_take isl_mat *mat,
371	int row, int col, __isl_take isl_val *v)
372{
373	if (!v)
374		return isl_mat_free(mat);
375	if (!isl_val_is_int(v))
376		isl_die(isl_val_get_ctx(v), isl_error_invalid,
377			"expecting integer value", goto error);
378	mat = isl_mat_set_element(mat, row, col, v->n);
379	isl_val_free(v);
380	return mat;
381error:
382	isl_val_free(v);
383	return isl_mat_free(mat);
384}
385
386__isl_give isl_mat *isl_mat_diag(isl_ctx *ctx, unsigned n_row, isl_int d)
387{
388	int i;
389	struct isl_mat *mat;
390
391	mat = isl_mat_alloc(ctx, n_row, n_row);
392	if (!mat)
393		return NULL;
394	for (i = 0; i < n_row; ++i) {
395		isl_seq_clr(mat->row[i], i);
396		isl_int_set(mat->row[i][i], d);
397		isl_seq_clr(mat->row[i]+i+1, n_row-(i+1));
398	}
399
400	return mat;
401}
402
403/* Create an "n_row" by "n_col" matrix with zero elements.
404 */
405__isl_give isl_mat *isl_mat_zero(isl_ctx *ctx, unsigned n_row, unsigned n_col)
406{
407	int i;
408	isl_mat *mat;
409
410	mat = isl_mat_alloc(ctx, n_row, n_col);
411	if (!mat)
412		return NULL;
413	for (i = 0; i < n_row; ++i)
414		isl_seq_clr(mat->row[i], n_col);
415
416	return mat;
417}
418
419__isl_give isl_mat *isl_mat_identity(isl_ctx *ctx, unsigned n_row)
420{
421	if (!ctx)
422		return NULL;
423	return isl_mat_diag(ctx, n_row, ctx->one);
424}
425
426/* Is "mat" a (possibly scaled) identity matrix?
427 */
428isl_bool isl_mat_is_scaled_identity(__isl_keep isl_mat *mat)
429{
430	int i;
431
432	if (!mat)
433		return isl_bool_error;
434	if (mat->n_row != mat->n_col)
435		return isl_bool_false;
436
437	for (i = 0; i < mat->n_row; ++i) {
438		if (isl_seq_first_non_zero(mat->row[i], i) != -1)
439			return isl_bool_false;
440		if (isl_int_ne(mat->row[0][0], mat->row[i][i]))
441			return isl_bool_false;
442		if (isl_seq_first_non_zero(mat->row[i] + i + 1,
443					    mat->n_col - (i + 1)) != -1)
444			return isl_bool_false;
445	}
446
447	return isl_bool_true;
448}
449
450__isl_give isl_vec *isl_mat_vec_product(__isl_take isl_mat *mat,
451	__isl_take isl_vec *vec)
452{
453	int i;
454	struct isl_vec *prod;
455
456	if (!mat || !vec)
457		goto error;
458
459	isl_assert(mat->ctx, mat->n_col == vec->size, goto error);
460
461	prod = isl_vec_alloc(mat->ctx, mat->n_row);
462	if (!prod)
463		goto error;
464
465	for (i = 0; i < prod->size; ++i)
466		isl_seq_inner_product(mat->row[i], vec->el, vec->size,
467					&prod->block.data[i]);
468	isl_mat_free(mat);
469	isl_vec_free(vec);
470	return prod;
471error:
472	isl_mat_free(mat);
473	isl_vec_free(vec);
474	return NULL;
475}
476
477__isl_give isl_vec *isl_mat_vec_inverse_product(__isl_take isl_mat *mat,
478	__isl_take isl_vec *vec)
479{
480	struct isl_mat *vec_mat;
481	int i;
482
483	if (!mat || !vec)
484		goto error;
485	vec_mat = isl_mat_alloc(vec->ctx, vec->size, 1);
486	if (!vec_mat)
487		goto error;
488	for (i = 0; i < vec->size; ++i)
489		isl_int_set(vec_mat->row[i][0], vec->el[i]);
490	vec_mat = isl_mat_inverse_product(mat, vec_mat);
491	isl_vec_free(vec);
492	if (!vec_mat)
493		return NULL;
494	vec = isl_vec_alloc(vec_mat->ctx, vec_mat->n_row);
495	if (vec)
496		for (i = 0; i < vec->size; ++i)
497			isl_int_set(vec->el[i], vec_mat->row[i][0]);
498	isl_mat_free(vec_mat);
499	return vec;
500error:
501	isl_mat_free(mat);
502	isl_vec_free(vec);
503	return NULL;
504}
505
506__isl_give isl_vec *isl_vec_mat_product(__isl_take isl_vec *vec,
507	__isl_take isl_mat *mat)
508{
509	int i, j;
510	struct isl_vec *prod;
511
512	if (!mat || !vec)
513		goto error;
514
515	isl_assert(mat->ctx, mat->n_row == vec->size, goto error);
516
517	prod = isl_vec_alloc(mat->ctx, mat->n_col);
518	if (!prod)
519		goto error;
520
521	for (i = 0; i < prod->size; ++i) {
522		isl_int_set_si(prod->el[i], 0);
523		for (j = 0; j < vec->size; ++j)
524			isl_int_addmul(prod->el[i], vec->el[j], mat->row[j][i]);
525	}
526	isl_mat_free(mat);
527	isl_vec_free(vec);
528	return prod;
529error:
530	isl_mat_free(mat);
531	isl_vec_free(vec);
532	return NULL;
533}
534
535__isl_give isl_mat *isl_mat_aff_direct_sum(__isl_take isl_mat *left,
536	__isl_take isl_mat *right)
537{
538	int i;
539	struct isl_mat *sum;
540
541	if (!left || !right)
542		goto error;
543
544	isl_assert(left->ctx, left->n_row == right->n_row, goto error);
545	isl_assert(left->ctx, left->n_row >= 1, goto error);
546	isl_assert(left->ctx, left->n_col >= 1, goto error);
547	isl_assert(left->ctx, right->n_col >= 1, goto error);
548	isl_assert(left->ctx,
549	    isl_seq_first_non_zero(left->row[0]+1, left->n_col-1) == -1,
550	    goto error);
551	isl_assert(left->ctx,
552	    isl_seq_first_non_zero(right->row[0]+1, right->n_col-1) == -1,
553	    goto error);
554
555	sum = isl_mat_alloc(left->ctx, left->n_row, left->n_col + right->n_col - 1);
556	if (!sum)
557		goto error;
558	isl_int_lcm(sum->row[0][0], left->row[0][0], right->row[0][0]);
559	isl_int_divexact(left->row[0][0], sum->row[0][0], left->row[0][0]);
560	isl_int_divexact(right->row[0][0], sum->row[0][0], right->row[0][0]);
561
562	isl_seq_clr(sum->row[0]+1, sum->n_col-1);
563	for (i = 1; i < sum->n_row; ++i) {
564		isl_int_mul(sum->row[i][0], left->row[0][0], left->row[i][0]);
565		isl_int_addmul(sum->row[i][0],
566				right->row[0][0], right->row[i][0]);
567		isl_seq_scale(sum->row[i]+1, left->row[i]+1, left->row[0][0],
568				left->n_col-1);
569		isl_seq_scale(sum->row[i]+left->n_col,
570				right->row[i]+1, right->row[0][0],
571				right->n_col-1);
572	}
573
574	isl_int_divexact(left->row[0][0], sum->row[0][0], left->row[0][0]);
575	isl_int_divexact(right->row[0][0], sum->row[0][0], right->row[0][0]);
576	isl_mat_free(left);
577	isl_mat_free(right);
578	return sum;
579error:
580	isl_mat_free(left);
581	isl_mat_free(right);
582	return NULL;
583}
584
585static void exchange(__isl_keep isl_mat *M, __isl_keep isl_mat **U,
586	__isl_keep isl_mat **Q, unsigned row, unsigned i, unsigned j)
587{
588	int r;
589	for (r = row; r < M->n_row; ++r)
590		isl_int_swap(M->row[r][i], M->row[r][j]);
591	if (U) {
592		for (r = 0; r < (*U)->n_row; ++r)
593			isl_int_swap((*U)->row[r][i], (*U)->row[r][j]);
594	}
595	if (Q)
596		isl_mat_swap_rows(*Q, i, j);
597}
598
599static void subtract(__isl_keep isl_mat *M, __isl_keep isl_mat **U,
600	__isl_keep isl_mat **Q, unsigned row, unsigned i, unsigned j, isl_int m)
601{
602	int r;
603	for (r = row; r < M->n_row; ++r)
604		isl_int_submul(M->row[r][j], m, M->row[r][i]);
605	if (U) {
606		for (r = 0; r < (*U)->n_row; ++r)
607			isl_int_submul((*U)->row[r][j], m, (*U)->row[r][i]);
608	}
609	if (Q) {
610		for (r = 0; r < (*Q)->n_col; ++r)
611			isl_int_addmul((*Q)->row[i][r], m, (*Q)->row[j][r]);
612	}
613}
614
615static void oppose(__isl_keep isl_mat *M, __isl_keep isl_mat **U,
616	__isl_keep isl_mat **Q, unsigned row, unsigned col)
617{
618	int r;
619	for (r = row; r < M->n_row; ++r)
620		isl_int_neg(M->row[r][col], M->row[r][col]);
621	if (U) {
622		for (r = 0; r < (*U)->n_row; ++r)
623			isl_int_neg((*U)->row[r][col], (*U)->row[r][col]);
624	}
625	if (Q)
626		isl_seq_neg((*Q)->row[col], (*Q)->row[col], (*Q)->n_col);
627}
628
629/* Given matrix M, compute
630 *
631 *		M U = H
632 *		M   = H Q
633 *
634 * with U and Q unimodular matrices and H a matrix in column echelon form
635 * such that on each echelon row the entries in the non-echelon column
636 * are non-negative (if neg == 0) or non-positive (if neg == 1)
637 * and strictly smaller (in absolute value) than the entries in the echelon
638 * column.
639 * If U or Q are NULL, then these matrices are not computed.
640 */
641__isl_give isl_mat *isl_mat_left_hermite(__isl_take isl_mat *M, int neg,
642	__isl_give isl_mat **U, __isl_give isl_mat **Q)
643{
644	isl_int c;
645	int row, col;
646
647	if (U)
648		*U = NULL;
649	if (Q)
650		*Q = NULL;
651	if (!M)
652		goto error;
653	if (U) {
654		*U = isl_mat_identity(M->ctx, M->n_col);
655		if (!*U)
656			goto error;
657	}
658	if (Q) {
659		*Q = isl_mat_identity(M->ctx, M->n_col);
660		if (!*Q)
661			goto error;
662	}
663
664	if (M->n_col == 0)
665		return M;
666
667	M = isl_mat_cow(M);
668	if (!M)
669		goto error;
670
671	col = 0;
672	isl_int_init(c);
673	for (row = 0; row < M->n_row; ++row) {
674		int first, i, off;
675		first = isl_seq_abs_min_non_zero(M->row[row]+col, M->n_col-col);
676		if (first == -1)
677			continue;
678		first += col;
679		if (first != col)
680			exchange(M, U, Q, row, first, col);
681		if (isl_int_is_neg(M->row[row][col]))
682			oppose(M, U, Q, row, col);
683		first = col+1;
684		while ((off = isl_seq_first_non_zero(M->row[row]+first,
685						       M->n_col-first)) != -1) {
686			first += off;
687			isl_int_fdiv_q(c, M->row[row][first], M->row[row][col]);
688			subtract(M, U, Q, row, col, first, c);
689			if (!isl_int_is_zero(M->row[row][first]))
690				exchange(M, U, Q, row, first, col);
691			else
692				++first;
693		}
694		for (i = 0; i < col; ++i) {
695			if (isl_int_is_zero(M->row[row][i]))
696				continue;
697			if (neg)
698				isl_int_cdiv_q(c, M->row[row][i], M->row[row][col]);
699			else
700				isl_int_fdiv_q(c, M->row[row][i], M->row[row][col]);
701			if (isl_int_is_zero(c))
702				continue;
703			subtract(M, U, Q, row, col, i, c);
704		}
705		++col;
706	}
707	isl_int_clear(c);
708
709	return M;
710error:
711	if (Q) {
712		isl_mat_free(*Q);
713		*Q = NULL;
714	}
715	if (U) {
716		isl_mat_free(*U);
717		*U = NULL;
718	}
719	isl_mat_free(M);
720	return NULL;
721}
722
723/* Use row "row" of "mat" to eliminate column "col" from all other rows.
724 */
725static __isl_give isl_mat *eliminate(__isl_take isl_mat *mat, int row, int col)
726{
727	int k;
728	isl_size nr, nc;
729	isl_ctx *ctx;
730
731	nr = isl_mat_rows(mat);
732	nc = isl_mat_cols(mat);
733	if (nr < 0 || nc < 0)
734		return isl_mat_free(mat);
735
736	ctx = isl_mat_get_ctx(mat);
737
738	for (k = 0; k < nr; ++k) {
739		if (k == row)
740			continue;
741		if (isl_int_is_zero(mat->row[k][col]))
742			continue;
743		mat = isl_mat_cow(mat);
744		if (!mat)
745			return NULL;
746		isl_seq_elim(mat->row[k], mat->row[row], col, nc, NULL);
747		isl_seq_normalize(ctx, mat->row[k], nc);
748	}
749
750	return mat;
751}
752
753/* Perform Gaussian elimination on the rows of "mat", but start
754 * from the final row and the final column.
755 * Any zero rows that result from the elimination are removed.
756 *
757 * In particular, for each column from last to first,
758 * look for the last row with a non-zero coefficient in that column,
759 * move it last (but before other rows moved last in previous steps) and
760 * use it to eliminate the column from the other rows.
761 */
762__isl_give isl_mat *isl_mat_reverse_gauss(__isl_take isl_mat *mat)
763{
764	int k, row, last;
765	isl_size nr, nc;
766
767	nr = isl_mat_rows(mat);
768	nc = isl_mat_cols(mat);
769	if (nr < 0 || nc < 0)
770		return isl_mat_free(mat);
771
772	last = nc - 1;
773	for (row = nr - 1; row >= 0; --row) {
774		for (; last >= 0; --last) {
775			for (k = row; k >= 0; --k)
776				if (!isl_int_is_zero(mat->row[k][last]))
777					break;
778			if (k >= 0)
779				break;
780		}
781		if (last < 0)
782			break;
783		if (k != row)
784			mat = isl_mat_swap_rows(mat, k, row);
785		if (!mat)
786			return NULL;
787		if (isl_int_is_neg(mat->row[row][last]))
788			mat = isl_mat_row_neg(mat, row);
789		mat = eliminate(mat, row, last);
790		if (!mat)
791			return NULL;
792	}
793	mat = isl_mat_drop_rows(mat, 0, row + 1);
794
795	return mat;
796}
797
798/* Negate the lexicographically negative rows of "mat" such that
799 * all rows in the result are lexicographically non-negative.
800 */
801__isl_give isl_mat *isl_mat_lexnonneg_rows(__isl_take isl_mat *mat)
802{
803	int i;
804	isl_size nr, nc;
805
806	nr = isl_mat_rows(mat);
807	nc = isl_mat_cols(mat);
808	if (nr < 0 || nc < 0)
809		return isl_mat_free(mat);
810
811	for (i = 0; i < nr; ++i) {
812		int pos;
813
814		pos = isl_seq_first_non_zero(mat->row[i], nc);
815		if (pos < 0)
816			continue;
817		if (isl_int_is_nonneg(mat->row[i][pos]))
818			continue;
819		mat = isl_mat_row_neg(mat, i);
820		if (!mat)
821			return NULL;
822	}
823
824	return mat;
825}
826
827/* Given a matrix "H" is column echelon form, what is the first
828 * zero column?  That is how many initial columns are non-zero?
829 * Start looking at column "first_col" and only consider
830 * the columns to be of size "n_row".
831 * "H" is assumed to be non-NULL.
832 *
833 * Since "H" is in column echelon form, the first non-zero entry
834 * in a column is always in a later position compared to the previous column.
835 */
836static int hermite_first_zero_col(__isl_keep isl_mat *H, int first_col,
837	int n_row)
838{
839	int row, col;
840
841	for (col = first_col, row = 0; col < H->n_col; ++col) {
842		for (; row < n_row; ++row)
843			if (!isl_int_is_zero(H->row[row][col]))
844				break;
845		if (row == n_row)
846			return col;
847	}
848
849	return H->n_col;
850}
851
852/* Return the rank of "mat", or isl_size_error in case of error.
853 */
854isl_size isl_mat_rank(__isl_keep isl_mat *mat)
855{
856	int rank;
857	isl_mat *H;
858
859	H = isl_mat_left_hermite(isl_mat_copy(mat), 0, NULL, NULL);
860	if (!H)
861		return isl_size_error;
862
863	rank = hermite_first_zero_col(H, 0, H->n_row);
864	isl_mat_free(H);
865
866	return rank;
867}
868
869__isl_give isl_mat *isl_mat_right_kernel(__isl_take isl_mat *mat)
870{
871	int rank;
872	struct isl_mat *U = NULL;
873	struct isl_mat *K;
874
875	mat = isl_mat_left_hermite(mat, 0, &U, NULL);
876	if (!mat || !U)
877		goto error;
878
879	rank = hermite_first_zero_col(mat, 0, mat->n_row);
880	K = isl_mat_alloc(U->ctx, U->n_row, U->n_col - rank);
881	if (!K)
882		goto error;
883	isl_mat_sub_copy(K->ctx, K->row, U->row, U->n_row, 0, rank, U->n_col-rank);
884	isl_mat_free(mat);
885	isl_mat_free(U);
886	return K;
887error:
888	isl_mat_free(mat);
889	isl_mat_free(U);
890	return NULL;
891}
892
893__isl_give isl_mat *isl_mat_lin_to_aff(__isl_take isl_mat *mat)
894{
895	int i;
896	struct isl_mat *mat2;
897
898	if (!mat)
899		return NULL;
900	mat2 = isl_mat_alloc(mat->ctx, 1+mat->n_row, 1+mat->n_col);
901	if (!mat2)
902		goto error;
903	isl_int_set_si(mat2->row[0][0], 1);
904	isl_seq_clr(mat2->row[0]+1, mat->n_col);
905	for (i = 0; i < mat->n_row; ++i) {
906		isl_int_set_si(mat2->row[1+i][0], 0);
907		isl_seq_cpy(mat2->row[1+i]+1, mat->row[i], mat->n_col);
908	}
909	isl_mat_free(mat);
910	return mat2;
911error:
912	isl_mat_free(mat);
913	return NULL;
914}
915
916/* Given two matrices M1 and M2, return the block matrix
917 *
918 *	[ M1  0  ]
919 *	[ 0   M2 ]
920 */
921__isl_give isl_mat *isl_mat_diagonal(__isl_take isl_mat *mat1,
922	__isl_take isl_mat *mat2)
923{
924	int i;
925	isl_mat *mat;
926
927	if (!mat1 || !mat2)
928		goto error;
929
930	mat = isl_mat_alloc(mat1->ctx, mat1->n_row + mat2->n_row,
931				       mat1->n_col + mat2->n_col);
932	if (!mat)
933		goto error;
934	for (i = 0; i < mat1->n_row; ++i) {
935		isl_seq_cpy(mat->row[i], mat1->row[i], mat1->n_col);
936		isl_seq_clr(mat->row[i] + mat1->n_col, mat2->n_col);
937	}
938	for (i = 0; i < mat2->n_row; ++i) {
939		isl_seq_clr(mat->row[mat1->n_row + i], mat1->n_col);
940		isl_seq_cpy(mat->row[mat1->n_row + i] + mat1->n_col,
941						    mat2->row[i], mat2->n_col);
942	}
943	isl_mat_free(mat1);
944	isl_mat_free(mat2);
945	return mat;
946error:
947	isl_mat_free(mat1);
948	isl_mat_free(mat2);
949	return NULL;
950}
951
952static int row_first_non_zero(isl_int **row, unsigned n_row, unsigned col)
953{
954	int i;
955
956	for (i = 0; i < n_row; ++i)
957		if (!isl_int_is_zero(row[i][col]))
958			return i;
959	return -1;
960}
961
962static int row_abs_min_non_zero(isl_int **row, unsigned n_row, unsigned col)
963{
964	int i, min = row_first_non_zero(row, n_row, col);
965	if (min < 0)
966		return -1;
967	for (i = min + 1; i < n_row; ++i) {
968		if (isl_int_is_zero(row[i][col]))
969			continue;
970		if (isl_int_abs_lt(row[i][col], row[min][col]))
971			min = i;
972	}
973	return min;
974}
975
976static isl_stat inv_exchange(__isl_keep isl_mat **left,
977	__isl_keep isl_mat **right, unsigned i, unsigned j)
978{
979	*left = isl_mat_swap_rows(*left, i, j);
980	*right = isl_mat_swap_rows(*right, i, j);
981
982	if (!*left || !*right)
983		return isl_stat_error;
984	return isl_stat_ok;
985}
986
987static void inv_oppose(
988	__isl_keep isl_mat *left, __isl_keep isl_mat *right, unsigned row)
989{
990	isl_seq_neg(left->row[row]+row, left->row[row]+row, left->n_col-row);
991	isl_seq_neg(right->row[row], right->row[row], right->n_col);
992}
993
994static void inv_subtract(__isl_keep isl_mat *left, __isl_keep isl_mat *right,
995	unsigned row, unsigned i, isl_int m)
996{
997	isl_int_neg(m, m);
998	isl_seq_combine(left->row[i]+row,
999			left->ctx->one, left->row[i]+row,
1000			m, left->row[row]+row,
1001			left->n_col-row);
1002	isl_seq_combine(right->row[i], right->ctx->one, right->row[i],
1003			m, right->row[row], right->n_col);
1004}
1005
1006/* Compute inv(left)*right
1007 */
1008__isl_give isl_mat *isl_mat_inverse_product(__isl_take isl_mat *left,
1009	__isl_take isl_mat *right)
1010{
1011	int row;
1012	isl_int a, b;
1013
1014	if (!left || !right)
1015		goto error;
1016
1017	isl_assert(left->ctx, left->n_row == left->n_col, goto error);
1018	isl_assert(left->ctx, left->n_row == right->n_row, goto error);
1019
1020	if (left->n_row == 0) {
1021		isl_mat_free(left);
1022		return right;
1023	}
1024
1025	left = isl_mat_cow(left);
1026	right = isl_mat_cow(right);
1027	if (!left || !right)
1028		goto error;
1029
1030	isl_int_init(a);
1031	isl_int_init(b);
1032	for (row = 0; row < left->n_row; ++row) {
1033		int pivot, first, i, off;
1034		pivot = row_abs_min_non_zero(left->row+row, left->n_row-row, row);
1035		if (pivot < 0) {
1036			isl_int_clear(a);
1037			isl_int_clear(b);
1038			isl_assert(left->ctx, pivot >= 0, goto error);
1039		}
1040		pivot += row;
1041		if (pivot != row)
1042			if (inv_exchange(&left, &right, pivot, row) < 0)
1043				goto error;
1044		if (isl_int_is_neg(left->row[row][row]))
1045			inv_oppose(left, right, row);
1046		first = row+1;
1047		while ((off = row_first_non_zero(left->row+first,
1048					left->n_row-first, row)) != -1) {
1049			first += off;
1050			isl_int_fdiv_q(a, left->row[first][row],
1051					left->row[row][row]);
1052			inv_subtract(left, right, row, first, a);
1053			if (!isl_int_is_zero(left->row[first][row])) {
1054				if (inv_exchange(&left, &right, row, first) < 0)
1055					goto error;
1056			} else {
1057				++first;
1058			}
1059		}
1060		for (i = 0; i < row; ++i) {
1061			if (isl_int_is_zero(left->row[i][row]))
1062				continue;
1063			isl_int_gcd(a, left->row[row][row], left->row[i][row]);
1064			isl_int_divexact(b, left->row[i][row], a);
1065			isl_int_divexact(a, left->row[row][row], a);
1066			isl_int_neg(b, b);
1067			isl_seq_combine(left->row[i] + i,
1068					a, left->row[i] + i,
1069					b, left->row[row] + i,
1070					left->n_col - i);
1071			isl_seq_combine(right->row[i], a, right->row[i],
1072					b, right->row[row], right->n_col);
1073		}
1074	}
1075	isl_int_clear(b);
1076
1077	isl_int_set(a, left->row[0][0]);
1078	for (row = 1; row < left->n_row; ++row)
1079		isl_int_lcm(a, a, left->row[row][row]);
1080	if (isl_int_is_zero(a)){
1081		isl_int_clear(a);
1082		isl_assert(left->ctx, 0, goto error);
1083	}
1084	for (row = 0; row < left->n_row; ++row) {
1085		isl_int_divexact(left->row[row][row], a, left->row[row][row]);
1086		if (isl_int_is_one(left->row[row][row]))
1087			continue;
1088		isl_seq_scale(right->row[row], right->row[row],
1089				left->row[row][row], right->n_col);
1090	}
1091	isl_int_clear(a);
1092
1093	isl_mat_free(left);
1094	return right;
1095error:
1096	isl_mat_free(left);
1097	isl_mat_free(right);
1098	return NULL;
1099}
1100
1101void isl_mat_col_scale(__isl_keep isl_mat *mat, unsigned col, isl_int m)
1102{
1103	int i;
1104
1105	for (i = 0; i < mat->n_row; ++i)
1106		isl_int_mul(mat->row[i][col], mat->row[i][col], m);
1107}
1108
1109void isl_mat_col_combine(__isl_keep isl_mat *mat, unsigned dst,
1110	isl_int m1, unsigned src1, isl_int m2, unsigned src2)
1111{
1112	int i;
1113	isl_int tmp;
1114
1115	isl_int_init(tmp);
1116	for (i = 0; i < mat->n_row; ++i) {
1117		isl_int_mul(tmp, m1, mat->row[i][src1]);
1118		isl_int_addmul(tmp, m2, mat->row[i][src2]);
1119		isl_int_set(mat->row[i][dst], tmp);
1120	}
1121	isl_int_clear(tmp);
1122}
1123
1124__isl_give isl_mat *isl_mat_right_inverse(__isl_take isl_mat *mat)
1125{
1126	struct isl_mat *inv;
1127	int row;
1128	isl_int a, b;
1129
1130	mat = isl_mat_cow(mat);
1131	if (!mat)
1132		return NULL;
1133
1134	inv = isl_mat_identity(mat->ctx, mat->n_col);
1135	inv = isl_mat_cow(inv);
1136	if (!inv)
1137		goto error;
1138
1139	isl_int_init(a);
1140	isl_int_init(b);
1141	for (row = 0; row < mat->n_row; ++row) {
1142		int pivot, first, i, off;
1143		pivot = isl_seq_abs_min_non_zero(mat->row[row]+row, mat->n_col-row);
1144		if (pivot < 0) {
1145			isl_int_clear(a);
1146			isl_int_clear(b);
1147			isl_assert(mat->ctx, pivot >= 0, goto error);
1148		}
1149		pivot += row;
1150		if (pivot != row)
1151			exchange(mat, &inv, NULL, row, pivot, row);
1152		if (isl_int_is_neg(mat->row[row][row]))
1153			oppose(mat, &inv, NULL, row, row);
1154		first = row+1;
1155		while ((off = isl_seq_first_non_zero(mat->row[row]+first,
1156						    mat->n_col-first)) != -1) {
1157			first += off;
1158			isl_int_fdiv_q(a, mat->row[row][first],
1159						    mat->row[row][row]);
1160			subtract(mat, &inv, NULL, row, row, first, a);
1161			if (!isl_int_is_zero(mat->row[row][first]))
1162				exchange(mat, &inv, NULL, row, row, first);
1163			else
1164				++first;
1165		}
1166		for (i = 0; i < row; ++i) {
1167			if (isl_int_is_zero(mat->row[row][i]))
1168				continue;
1169			isl_int_gcd(a, mat->row[row][row], mat->row[row][i]);
1170			isl_int_divexact(b, mat->row[row][i], a);
1171			isl_int_divexact(a, mat->row[row][row], a);
1172			isl_int_neg(a, a);
1173			isl_mat_col_combine(mat, i, a, i, b, row);
1174			isl_mat_col_combine(inv, i, a, i, b, row);
1175		}
1176	}
1177	isl_int_clear(b);
1178
1179	isl_int_set(a, mat->row[0][0]);
1180	for (row = 1; row < mat->n_row; ++row)
1181		isl_int_lcm(a, a, mat->row[row][row]);
1182	if (isl_int_is_zero(a)){
1183		isl_int_clear(a);
1184		goto error;
1185	}
1186	for (row = 0; row < mat->n_row; ++row) {
1187		isl_int_divexact(mat->row[row][row], a, mat->row[row][row]);
1188		if (isl_int_is_one(mat->row[row][row]))
1189			continue;
1190		isl_mat_col_scale(inv, row, mat->row[row][row]);
1191	}
1192	isl_int_clear(a);
1193
1194	isl_mat_free(mat);
1195
1196	return inv;
1197error:
1198	isl_mat_free(mat);
1199	isl_mat_free(inv);
1200	return NULL;
1201}
1202
1203__isl_give isl_mat *isl_mat_transpose(__isl_take isl_mat *mat)
1204{
1205	struct isl_mat *transpose = NULL;
1206	int i, j;
1207
1208	if (!mat)
1209		return NULL;
1210
1211	if (mat->n_col == mat->n_row) {
1212		mat = isl_mat_cow(mat);
1213		if (!mat)
1214			return NULL;
1215		for (i = 0; i < mat->n_row; ++i)
1216			for (j = i + 1; j < mat->n_col; ++j)
1217				isl_int_swap(mat->row[i][j], mat->row[j][i]);
1218		return mat;
1219	}
1220	transpose = isl_mat_alloc(mat->ctx, mat->n_col, mat->n_row);
1221	if (!transpose)
1222		goto error;
1223	for (i = 0; i < mat->n_row; ++i)
1224		for (j = 0; j < mat->n_col; ++j)
1225			isl_int_set(transpose->row[j][i], mat->row[i][j]);
1226	isl_mat_free(mat);
1227	return transpose;
1228error:
1229	isl_mat_free(mat);
1230	return NULL;
1231}
1232
1233__isl_give isl_mat *isl_mat_swap_cols(__isl_take isl_mat *mat,
1234	unsigned i, unsigned j)
1235{
1236	int r;
1237
1238	mat = isl_mat_cow(mat);
1239	if (check_col_range(mat, i, 1) < 0 ||
1240	    check_col_range(mat, j, 1) < 0)
1241		return isl_mat_free(mat);
1242
1243	for (r = 0; r < mat->n_row; ++r)
1244		isl_int_swap(mat->row[r][i], mat->row[r][j]);
1245	return mat;
1246}
1247
1248__isl_give isl_mat *isl_mat_swap_rows(__isl_take isl_mat *mat,
1249	unsigned i, unsigned j)
1250{
1251	isl_int *t;
1252
1253	if (!mat)
1254		return NULL;
1255	mat = isl_mat_cow(mat);
1256	if (check_row_range(mat, i, 1) < 0 ||
1257	    check_row_range(mat, j, 1) < 0)
1258		return isl_mat_free(mat);
1259
1260	t = mat->row[i];
1261	mat->row[i] = mat->row[j];
1262	mat->row[j] = t;
1263	return mat;
1264}
1265
1266/* Calculate the product of two matrices.
1267 *
1268 * This function is optimized for operand matrices that contain many zeros and
1269 * skips multiplications where we know one of the operands is zero.
1270 */
1271__isl_give isl_mat *isl_mat_product(__isl_take isl_mat *left,
1272	__isl_take isl_mat *right)
1273{
1274	int i, j, k;
1275	struct isl_mat *prod;
1276
1277	if (!left || !right)
1278		goto error;
1279	isl_assert(left->ctx, left->n_col == right->n_row, goto error);
1280	prod = isl_mat_alloc(left->ctx, left->n_row, right->n_col);
1281	if (!prod)
1282		goto error;
1283	if (left->n_col == 0) {
1284		for (i = 0; i < prod->n_row; ++i)
1285			isl_seq_clr(prod->row[i], prod->n_col);
1286		isl_mat_free(left);
1287		isl_mat_free(right);
1288		return prod;
1289	}
1290	for (i = 0; i < prod->n_row; ++i) {
1291		for (j = 0; j < prod->n_col; ++j)
1292			isl_int_mul(prod->row[i][j],
1293				    left->row[i][0], right->row[0][j]);
1294		for (k = 1; k < left->n_col; ++k) {
1295			if (isl_int_is_zero(left->row[i][k]))
1296				continue;
1297			for (j = 0; j < prod->n_col; ++j)
1298				isl_int_addmul(prod->row[i][j],
1299					    left->row[i][k], right->row[k][j]);
1300		}
1301	}
1302	isl_mat_free(left);
1303	isl_mat_free(right);
1304	return prod;
1305error:
1306	isl_mat_free(left);
1307	isl_mat_free(right);
1308	return NULL;
1309}
1310
1311/* Replace the variables x in the rows q by x' given by x = M x',
1312 * with M the matrix mat.
1313 *
1314 * If the number of new variables is greater than the original
1315 * number of variables, then the rows q have already been
1316 * preextended.  If the new number is smaller, then the coefficients
1317 * of the divs, which are not changed, need to be shifted down.
1318 * The row q may be the equalities, the inequalities or the
1319 * div expressions.  In the latter case, has_div is true and
1320 * we need to take into account the extra denominator column.
1321 */
1322static int preimage(struct isl_ctx *ctx, isl_int **q, unsigned n,
1323	unsigned n_div, int has_div, struct isl_mat *mat)
1324{
1325	int i;
1326	struct isl_mat *t;
1327	int e;
1328
1329	if (mat->n_col >= mat->n_row)
1330		e = 0;
1331	else
1332		e = mat->n_row - mat->n_col;
1333	if (has_div)
1334		for (i = 0; i < n; ++i)
1335			isl_int_mul(q[i][0], q[i][0], mat->row[0][0]);
1336	t = isl_mat_sub_alloc6(mat->ctx, q, 0, n, has_div, mat->n_row);
1337	t = isl_mat_product(t, mat);
1338	if (!t)
1339		return -1;
1340	for (i = 0; i < n; ++i) {
1341		isl_seq_swp_or_cpy(q[i] + has_div, t->row[i], t->n_col);
1342		isl_seq_cpy(q[i] + has_div + t->n_col,
1343			    q[i] + has_div + t->n_col + e, n_div);
1344		isl_seq_clr(q[i] + has_div + t->n_col + n_div, e);
1345	}
1346	isl_mat_free(t);
1347	return 0;
1348}
1349
1350/* Replace the variables x in bset by x' given by x = M x', with
1351 * M the matrix mat.
1352 *
1353 * If there are fewer variables x' then there are x, then we perform
1354 * the transformation in place, which means that, in principle,
1355 * this frees up some extra variables as the number
1356 * of columns remains constant, but we would have to extend
1357 * the div array too as the number of rows in this array is assumed
1358 * to be equal to extra.
1359 */
1360__isl_give isl_basic_set *isl_basic_set_preimage(
1361	__isl_take isl_basic_set *bset, __isl_take isl_mat *mat)
1362{
1363	struct isl_ctx *ctx;
1364
1365	if (!bset || !mat)
1366		goto error;
1367
1368	ctx = bset->ctx;
1369	bset = isl_basic_set_cow(bset);
1370	if (isl_basic_set_check_no_params(bset) < 0)
1371		goto error;
1372
1373	isl_assert(ctx, 1+bset->dim->n_out == mat->n_row, goto error);
1374	isl_assert(ctx, mat->n_col > 0, goto error);
1375
1376	if (mat->n_col > mat->n_row) {
1377		bset = isl_basic_set_add_dims(bset, isl_dim_set,
1378						mat->n_col - mat->n_row);
1379		if (!bset)
1380			goto error;
1381	} else if (mat->n_col < mat->n_row) {
1382		bset->dim = isl_space_cow(bset->dim);
1383		if (!bset->dim)
1384			goto error;
1385		bset->dim->n_out -= mat->n_row - mat->n_col;
1386	}
1387
1388	if (preimage(ctx, bset->eq, bset->n_eq, bset->n_div, 0,
1389			isl_mat_copy(mat)) < 0)
1390		goto error;
1391
1392	if (preimage(ctx, bset->ineq, bset->n_ineq, bset->n_div, 0,
1393			isl_mat_copy(mat)) < 0)
1394		goto error;
1395
1396	if (preimage(ctx, bset->div, bset->n_div, bset->n_div, 1, mat) < 0)
1397		goto error2;
1398
1399	ISL_F_CLR(bset, ISL_BASIC_SET_NO_IMPLICIT);
1400	ISL_F_CLR(bset, ISL_BASIC_SET_NO_REDUNDANT);
1401	ISL_F_CLR(bset, ISL_BASIC_SET_SORTED);
1402	ISL_F_CLR(bset, ISL_BASIC_SET_NORMALIZED_DIVS);
1403	ISL_F_CLR(bset, ISL_BASIC_SET_ALL_EQUALITIES);
1404
1405	bset = isl_basic_set_simplify(bset);
1406	bset = isl_basic_set_finalize(bset);
1407
1408	return bset;
1409error:
1410	isl_mat_free(mat);
1411error2:
1412	isl_basic_set_free(bset);
1413	return NULL;
1414}
1415
1416__isl_give isl_set *isl_set_preimage(
1417	__isl_take isl_set *set, __isl_take isl_mat *mat)
1418{
1419	int i;
1420
1421	set = isl_set_cow(set);
1422	if (!set)
1423		goto error;
1424
1425	for (i = 0; i < set->n; ++i) {
1426		set->p[i] = isl_basic_set_preimage(set->p[i],
1427						    isl_mat_copy(mat));
1428		if (!set->p[i])
1429			goto error;
1430	}
1431	if (mat->n_col != mat->n_row) {
1432		set->dim = isl_space_cow(set->dim);
1433		if (!set->dim)
1434			goto error;
1435		set->dim->n_out += mat->n_col;
1436		set->dim->n_out -= mat->n_row;
1437	}
1438	isl_mat_free(mat);
1439	ISL_F_CLR(set, ISL_SET_NORMALIZED);
1440	return set;
1441error:
1442	isl_set_free(set);
1443	isl_mat_free(mat);
1444	return NULL;
1445}
1446
1447/* Replace the variables x starting at "first_col" in the rows "rows"
1448 * of some coefficient matrix by x' with x = M x' with M the matrix mat.
1449 * That is, replace the corresponding coefficients c by c M.
1450 */
1451isl_stat isl_mat_sub_transform(isl_int **row, unsigned n_row,
1452	unsigned first_col, __isl_take isl_mat *mat)
1453{
1454	int i;
1455	isl_ctx *ctx;
1456	isl_mat *t;
1457
1458	if (!mat)
1459		return isl_stat_error;
1460	ctx = isl_mat_get_ctx(mat);
1461	t = isl_mat_sub_alloc6(ctx, row, 0, n_row, first_col, mat->n_row);
1462	t = isl_mat_product(t, mat);
1463	if (!t)
1464		return isl_stat_error;
1465	for (i = 0; i < n_row; ++i)
1466		isl_seq_swp_or_cpy(row[i] + first_col, t->row[i], t->n_col);
1467	isl_mat_free(t);
1468	return isl_stat_ok;
1469}
1470
1471void isl_mat_print_internal(__isl_keep isl_mat *mat, FILE *out, int indent)
1472{
1473	int i, j;
1474
1475	if (!mat) {
1476		fprintf(out, "%*snull mat\n", indent, "");
1477		return;
1478	}
1479
1480	if (mat->n_row == 0)
1481		fprintf(out, "%*s[]\n", indent, "");
1482
1483	for (i = 0; i < mat->n_row; ++i) {
1484		if (!i)
1485			fprintf(out, "%*s[[", indent, "");
1486		else
1487			fprintf(out, "%*s[", indent+1, "");
1488		for (j = 0; j < mat->n_col; ++j) {
1489			if (j)
1490			    fprintf(out, ",");
1491			isl_int_print(out, mat->row[i][j], 0);
1492		}
1493		if (i == mat->n_row-1)
1494			fprintf(out, "]]\n");
1495		else
1496			fprintf(out, "]\n");
1497	}
1498}
1499
1500void isl_mat_dump(__isl_keep isl_mat *mat)
1501{
1502	isl_mat_print_internal(mat, stderr, 0);
1503}
1504
1505__isl_give isl_mat *isl_mat_drop_cols(__isl_take isl_mat *mat,
1506	unsigned col, unsigned n)
1507{
1508	int r;
1509
1510	if (n == 0)
1511		return mat;
1512
1513	mat = isl_mat_cow(mat);
1514	if (check_col_range(mat, col, n) < 0)
1515		return isl_mat_free(mat);
1516
1517	if (col != mat->n_col-n) {
1518		for (r = 0; r < mat->n_row; ++r)
1519			isl_seq_cpy(mat->row[r]+col, mat->row[r]+col+n,
1520					mat->n_col - col - n);
1521	}
1522	mat->n_col -= n;
1523	return mat;
1524}
1525
1526__isl_give isl_mat *isl_mat_drop_rows(__isl_take isl_mat *mat,
1527	unsigned row, unsigned n)
1528{
1529	int r;
1530
1531	mat = isl_mat_cow(mat);
1532	if (check_row_range(mat, row, n) < 0)
1533		return isl_mat_free(mat);
1534
1535	for (r = row; r+n < mat->n_row; ++r)
1536		mat->row[r] = mat->row[r+n];
1537
1538	mat->n_row -= n;
1539	return mat;
1540}
1541
1542__isl_give isl_mat *isl_mat_insert_cols(__isl_take isl_mat *mat,
1543				unsigned col, unsigned n)
1544{
1545	isl_mat *ext;
1546
1547	if (check_col_range(mat, col, 0) < 0)
1548		return isl_mat_free(mat);
1549	if (n == 0)
1550		return mat;
1551
1552	ext = isl_mat_alloc(mat->ctx, mat->n_row, mat->n_col + n);
1553	if (!ext)
1554		goto error;
1555
1556	isl_mat_sub_copy(mat->ctx, ext->row, mat->row, mat->n_row, 0, 0, col);
1557	isl_mat_sub_copy(mat->ctx, ext->row, mat->row, mat->n_row,
1558				col + n, col, mat->n_col - col);
1559
1560	isl_mat_free(mat);
1561	return ext;
1562error:
1563	isl_mat_free(mat);
1564	return NULL;
1565}
1566
1567__isl_give isl_mat *isl_mat_insert_zero_cols(__isl_take isl_mat *mat,
1568	unsigned first, unsigned n)
1569{
1570	int i;
1571
1572	if (!mat)
1573		return NULL;
1574	mat = isl_mat_insert_cols(mat, first, n);
1575	if (!mat)
1576		return NULL;
1577
1578	for (i = 0; i < mat->n_row; ++i)
1579		isl_seq_clr(mat->row[i] + first, n);
1580
1581	return mat;
1582}
1583
1584__isl_give isl_mat *isl_mat_add_zero_cols(__isl_take isl_mat *mat, unsigned n)
1585{
1586	if (!mat)
1587		return NULL;
1588
1589	return isl_mat_insert_zero_cols(mat, mat->n_col, n);
1590}
1591
1592__isl_give isl_mat *isl_mat_insert_rows(__isl_take isl_mat *mat,
1593				unsigned row, unsigned n)
1594{
1595	isl_mat *ext;
1596
1597	if (check_row_range(mat, row, 0) < 0)
1598		return isl_mat_free(mat);
1599	if (n == 0)
1600		return mat;
1601
1602	ext = isl_mat_alloc(mat->ctx, mat->n_row + n, mat->n_col);
1603	if (!ext)
1604		goto error;
1605
1606	isl_mat_sub_copy(mat->ctx, ext->row, mat->row, row, 0, 0, mat->n_col);
1607	isl_mat_sub_copy(mat->ctx, ext->row + row + n, mat->row + row,
1608				mat->n_row - row, 0, 0, mat->n_col);
1609
1610	isl_mat_free(mat);
1611	return ext;
1612error:
1613	isl_mat_free(mat);
1614	return NULL;
1615}
1616
1617__isl_give isl_mat *isl_mat_add_rows(__isl_take isl_mat *mat, unsigned n)
1618{
1619	if (!mat)
1620		return NULL;
1621
1622	return isl_mat_insert_rows(mat, mat->n_row, n);
1623}
1624
1625__isl_give isl_mat *isl_mat_insert_zero_rows(__isl_take isl_mat *mat,
1626	unsigned row, unsigned n)
1627{
1628	int i;
1629
1630	mat = isl_mat_insert_rows(mat, row, n);
1631	if (!mat)
1632		return NULL;
1633
1634	for (i = 0; i < n; ++i)
1635		isl_seq_clr(mat->row[row + i], mat->n_col);
1636
1637	return mat;
1638}
1639
1640__isl_give isl_mat *isl_mat_add_zero_rows(__isl_take isl_mat *mat, unsigned n)
1641{
1642	if (!mat)
1643		return NULL;
1644
1645	return isl_mat_insert_zero_rows(mat, mat->n_row, n);
1646}
1647
1648void isl_mat_col_submul(__isl_keep isl_mat *mat,
1649			int dst_col, isl_int f, int src_col)
1650{
1651	int i;
1652
1653	for (i = 0; i < mat->n_row; ++i)
1654		isl_int_submul(mat->row[i][dst_col], f, mat->row[i][src_col]);
1655}
1656
1657void isl_mat_col_add(__isl_keep isl_mat *mat, int dst_col, int src_col)
1658{
1659	int i;
1660
1661	if (!mat)
1662		return;
1663
1664	for (i = 0; i < mat->n_row; ++i)
1665		isl_int_add(mat->row[i][dst_col],
1666			    mat->row[i][dst_col], mat->row[i][src_col]);
1667}
1668
1669void isl_mat_col_mul(__isl_keep isl_mat *mat, int dst_col, isl_int f,
1670	int src_col)
1671{
1672	int i;
1673
1674	for (i = 0; i < mat->n_row; ++i)
1675		isl_int_mul(mat->row[i][dst_col], f, mat->row[i][src_col]);
1676}
1677
1678/* Add "f" times column "src_col" to column "dst_col" of "mat" and
1679 * return the result.
1680 */
1681__isl_give isl_mat *isl_mat_col_addmul(__isl_take isl_mat *mat, int dst_col,
1682	isl_int f, int src_col)
1683{
1684	int i;
1685
1686	if (check_col(mat, dst_col) < 0 || check_col(mat, src_col) < 0)
1687		return isl_mat_free(mat);
1688
1689	for (i = 0; i < mat->n_row; ++i) {
1690		if (isl_int_is_zero(mat->row[i][src_col]))
1691			continue;
1692		mat = isl_mat_cow(mat);
1693		if (!mat)
1694			return NULL;
1695		isl_int_addmul(mat->row[i][dst_col], f, mat->row[i][src_col]);
1696	}
1697
1698	return mat;
1699}
1700
1701/* Negate column "col" of "mat" and return the result.
1702 */
1703__isl_give isl_mat *isl_mat_col_neg(__isl_take isl_mat *mat, int col)
1704{
1705	int i;
1706
1707	if (check_col(mat, col) < 0)
1708		return isl_mat_free(mat);
1709
1710	for (i = 0; i < mat->n_row; ++i) {
1711		if (isl_int_is_zero(mat->row[i][col]))
1712			continue;
1713		mat = isl_mat_cow(mat);
1714		if (!mat)
1715			return NULL;
1716		isl_int_neg(mat->row[i][col], mat->row[i][col]);
1717	}
1718
1719	return mat;
1720}
1721
1722/* Negate row "row" of "mat" and return the result.
1723 */
1724__isl_give isl_mat *isl_mat_row_neg(__isl_take isl_mat *mat, int row)
1725{
1726	if (check_row(mat, row) < 0)
1727		return isl_mat_free(mat);
1728	if (isl_seq_first_non_zero(mat->row[row], mat->n_col) == -1)
1729		return mat;
1730	mat = isl_mat_cow(mat);
1731	if (!mat)
1732		return NULL;
1733	isl_seq_neg(mat->row[row], mat->row[row], mat->n_col);
1734	return mat;
1735}
1736
1737__isl_give isl_mat *isl_mat_unimodular_complete(__isl_take isl_mat *M, int row)
1738{
1739	int r;
1740	struct isl_mat *H = NULL, *Q = NULL;
1741
1742	if (!M)
1743		return NULL;
1744
1745	isl_assert(M->ctx, M->n_row == M->n_col, goto error);
1746	M->n_row = row;
1747	H = isl_mat_left_hermite(isl_mat_copy(M), 0, NULL, &Q);
1748	M->n_row = M->n_col;
1749	if (!H)
1750		goto error;
1751	for (r = 0; r < row; ++r)
1752		isl_assert(M->ctx, isl_int_is_one(H->row[r][r]), goto error);
1753	for (r = row; r < M->n_row; ++r)
1754		isl_seq_cpy(M->row[r], Q->row[r], M->n_col);
1755	isl_mat_free(H);
1756	isl_mat_free(Q);
1757	return M;
1758error:
1759	isl_mat_free(H);
1760	isl_mat_free(Q);
1761	isl_mat_free(M);
1762	return NULL;
1763}
1764
1765__isl_give isl_mat *isl_mat_concat(__isl_take isl_mat *top,
1766	__isl_take isl_mat *bot)
1767{
1768	struct isl_mat *mat;
1769
1770	if (!top || !bot)
1771		goto error;
1772
1773	isl_assert(top->ctx, top->n_col == bot->n_col, goto error);
1774	if (top->n_row == 0) {
1775		isl_mat_free(top);
1776		return bot;
1777	}
1778	if (bot->n_row == 0) {
1779		isl_mat_free(bot);
1780		return top;
1781	}
1782
1783	mat = isl_mat_alloc(top->ctx, top->n_row + bot->n_row, top->n_col);
1784	if (!mat)
1785		goto error;
1786	isl_mat_sub_copy(mat->ctx, mat->row, top->row, top->n_row,
1787			 0, 0, mat->n_col);
1788	isl_mat_sub_copy(mat->ctx, mat->row + top->n_row, bot->row, bot->n_row,
1789			 0, 0, mat->n_col);
1790	isl_mat_free(top);
1791	isl_mat_free(bot);
1792	return mat;
1793error:
1794	isl_mat_free(top);
1795	isl_mat_free(bot);
1796	return NULL;
1797}
1798
1799isl_bool isl_mat_is_equal(__isl_keep isl_mat *mat1, __isl_keep isl_mat *mat2)
1800{
1801	int i;
1802
1803	if (!mat1 || !mat2)
1804		return isl_bool_error;
1805
1806	if (mat1->n_row != mat2->n_row)
1807		return isl_bool_false;
1808
1809	if (mat1->n_col != mat2->n_col)
1810		return isl_bool_false;
1811
1812	for (i = 0; i < mat1->n_row; ++i)
1813		if (!isl_seq_eq(mat1->row[i], mat2->row[i], mat1->n_col))
1814			return isl_bool_false;
1815
1816	return isl_bool_true;
1817}
1818
1819__isl_give isl_mat *isl_mat_from_row_vec(__isl_take isl_vec *vec)
1820{
1821	struct isl_mat *mat;
1822
1823	if (!vec)
1824		return NULL;
1825	mat = isl_mat_alloc(vec->ctx, 1, vec->size);
1826	if (!mat)
1827		goto error;
1828
1829	isl_seq_cpy(mat->row[0], vec->el, vec->size);
1830
1831	isl_vec_free(vec);
1832	return mat;
1833error:
1834	isl_vec_free(vec);
1835	return NULL;
1836}
1837
1838/* Return a copy of row "row" of "mat" as an isl_vec.
1839 */
1840__isl_give isl_vec *isl_mat_get_row(__isl_keep isl_mat *mat, unsigned row)
1841{
1842	isl_vec *v;
1843
1844	if (!mat)
1845		return NULL;
1846	if (row >= mat->n_row)
1847		isl_die(mat->ctx, isl_error_invalid, "row out of range",
1848			return NULL);
1849
1850	v = isl_vec_alloc(isl_mat_get_ctx(mat), mat->n_col);
1851	if (!v)
1852		return NULL;
1853	isl_seq_cpy(v->el, mat->row[row], mat->n_col);
1854
1855	return v;
1856}
1857
1858__isl_give isl_mat *isl_mat_vec_concat(__isl_take isl_mat *top,
1859	__isl_take isl_vec *bot)
1860{
1861	return isl_mat_concat(top, isl_mat_from_row_vec(bot));
1862}
1863
1864__isl_give isl_mat *isl_mat_move_cols(__isl_take isl_mat *mat,
1865	unsigned dst_col, unsigned src_col, unsigned n)
1866{
1867	isl_mat *res;
1868
1869	if (!mat)
1870		return NULL;
1871	if (n == 0 || dst_col == src_col)
1872		return mat;
1873
1874	res = isl_mat_alloc(mat->ctx, mat->n_row, mat->n_col);
1875	if (!res)
1876		goto error;
1877
1878	if (dst_col < src_col) {
1879		isl_mat_sub_copy(res->ctx, res->row, mat->row, mat->n_row,
1880				 0, 0, dst_col);
1881		isl_mat_sub_copy(res->ctx, res->row, mat->row, mat->n_row,
1882				 dst_col, src_col, n);
1883		isl_mat_sub_copy(res->ctx, res->row, mat->row, mat->n_row,
1884				 dst_col + n, dst_col, src_col - dst_col);
1885		isl_mat_sub_copy(res->ctx, res->row, mat->row, mat->n_row,
1886				 src_col + n, src_col + n,
1887				 res->n_col - src_col - n);
1888	} else {
1889		isl_mat_sub_copy(res->ctx, res->row, mat->row, mat->n_row,
1890				 0, 0, src_col);
1891		isl_mat_sub_copy(res->ctx, res->row, mat->row, mat->n_row,
1892				 src_col, src_col + n, dst_col - src_col);
1893		isl_mat_sub_copy(res->ctx, res->row, mat->row, mat->n_row,
1894				 dst_col, src_col, n);
1895		isl_mat_sub_copy(res->ctx, res->row, mat->row, mat->n_row,
1896				 dst_col + n, dst_col + n,
1897				 res->n_col - dst_col - n);
1898	}
1899	isl_mat_free(mat);
1900
1901	return res;
1902error:
1903	isl_mat_free(mat);
1904	return NULL;
1905}
1906
1907/* Return the gcd of the elements in row "row" of "mat" in *gcd.
1908 * Return isl_stat_ok on success and isl_stat_error on failure.
1909 */
1910isl_stat isl_mat_row_gcd(__isl_keep isl_mat *mat, int row, isl_int *gcd)
1911{
1912	if (check_row(mat, row) < 0)
1913		return isl_stat_error;
1914
1915	isl_seq_gcd(mat->row[row], mat->n_col, gcd);
1916
1917	return isl_stat_ok;
1918}
1919
1920void isl_mat_gcd(__isl_keep isl_mat *mat, isl_int *gcd)
1921{
1922	int i;
1923	isl_int g;
1924
1925	isl_int_set_si(*gcd, 0);
1926	if (!mat)
1927		return;
1928
1929	isl_int_init(g);
1930	for (i = 0; i < mat->n_row; ++i) {
1931		isl_seq_gcd(mat->row[i], mat->n_col, &g);
1932		isl_int_gcd(*gcd, *gcd, g);
1933	}
1934	isl_int_clear(g);
1935}
1936
1937/* Return the result of scaling "mat" by a factor of "m".
1938 */
1939__isl_give isl_mat *isl_mat_scale(__isl_take isl_mat *mat, isl_int m)
1940{
1941	int i;
1942
1943	if (isl_int_is_one(m))
1944		return mat;
1945
1946	mat = isl_mat_cow(mat);
1947	if (!mat)
1948		return NULL;
1949
1950	for (i = 0; i < mat->n_row; ++i)
1951		isl_seq_scale(mat->row[i], mat->row[i], m, mat->n_col);
1952
1953	return mat;
1954}
1955
1956__isl_give isl_mat *isl_mat_scale_down(__isl_take isl_mat *mat, isl_int m)
1957{
1958	int i;
1959
1960	if (isl_int_is_one(m))
1961		return mat;
1962
1963	mat = isl_mat_cow(mat);
1964	if (!mat)
1965		return NULL;
1966
1967	for (i = 0; i < mat->n_row; ++i)
1968		isl_seq_scale_down(mat->row[i], mat->row[i], m, mat->n_col);
1969
1970	return mat;
1971}
1972
1973__isl_give isl_mat *isl_mat_scale_down_row(__isl_take isl_mat *mat, int row,
1974	isl_int m)
1975{
1976	if (isl_int_is_one(m))
1977		return mat;
1978
1979	mat = isl_mat_cow(mat);
1980	if (!mat)
1981		return NULL;
1982
1983	isl_seq_scale_down(mat->row[row], mat->row[row], m, mat->n_col);
1984
1985	return mat;
1986}
1987
1988__isl_give isl_mat *isl_mat_normalize(__isl_take isl_mat *mat)
1989{
1990	isl_int gcd;
1991
1992	if (!mat)
1993		return NULL;
1994
1995	isl_int_init(gcd);
1996	isl_mat_gcd(mat, &gcd);
1997	mat = isl_mat_scale_down(mat, gcd);
1998	isl_int_clear(gcd);
1999
2000	return mat;
2001}
2002
2003__isl_give isl_mat *isl_mat_normalize_row(__isl_take isl_mat *mat, int row)
2004{
2005	mat = isl_mat_cow(mat);
2006	if (!mat)
2007		return NULL;
2008
2009	isl_seq_normalize(mat->ctx, mat->row[row], mat->n_col);
2010
2011	return mat;
2012}
2013
2014/* Number of initial non-zero columns.
2015 */
2016int isl_mat_initial_non_zero_cols(__isl_keep isl_mat *mat)
2017{
2018	int i;
2019
2020	if (!mat)
2021		return -1;
2022
2023	for (i = 0; i < mat->n_col; ++i)
2024		if (row_first_non_zero(mat->row, mat->n_row, i) < 0)
2025			break;
2026
2027	return i;
2028}
2029
2030/* Return a basis for the space spanned by the rows of "mat".
2031 * Any basis will do, so simply perform Gaussian elimination and
2032 * remove the empty rows.
2033 */
2034__isl_give isl_mat *isl_mat_row_basis(__isl_take isl_mat *mat)
2035{
2036	return isl_mat_reverse_gauss(mat);
2037}
2038
2039/* Return rows that extend a basis of "mat1" to one
2040 * that covers both "mat1" and "mat2".
2041 * The Hermite normal form of the concatenation of the two matrices is
2042 *
2043 *	                     [ Q1 ]
2044 *	[ M1 ] = [ H1 0  0 ] [ Q2 ]
2045 *	[ M2 ] = [ H2 H3 0 ] [ Q3 ]
2046 *
2047 * The number of columns in H1 and H3 determine the number of rows
2048 * in Q1 and Q2.  Q1 is a basis for M1, while Q2 extends this basis
2049 * to also cover M2.
2050 */
2051__isl_give isl_mat *isl_mat_row_basis_extension(
2052	__isl_take isl_mat *mat1, __isl_take isl_mat *mat2)
2053{
2054	isl_size n_row;
2055	int r1, r;
2056	isl_size n1;
2057	isl_mat *H, *Q;
2058
2059	n1 = isl_mat_rows(mat1);
2060	H = isl_mat_concat(mat1, mat2);
2061	H = isl_mat_left_hermite(H, 0, NULL, &Q);
2062	if (n1 < 0 || !H || !Q)
2063		goto error;
2064
2065	r1 = hermite_first_zero_col(H, 0, n1);
2066	r = hermite_first_zero_col(H, r1, H->n_row);
2067	n_row = isl_mat_rows(Q);
2068	if (n_row < 0)
2069		goto error;
2070	Q = isl_mat_drop_rows(Q, r, n_row - r);
2071	Q = isl_mat_drop_rows(Q, 0, r1);
2072
2073	isl_mat_free(H);
2074	return Q;
2075error:
2076	isl_mat_free(H);
2077	isl_mat_free(Q);
2078	return NULL;
2079}
2080
2081/* Are the rows of "mat1" linearly independent of those of "mat2"?
2082 * That is, is there no linear dependence among the combined rows
2083 * that is not already present in either "mat1" or "mat2"?
2084 * In other words, is the rank of "mat1" and "mat2" combined equal
2085 * to the sum of the ranks of "mat1" and "mat2"?
2086 */
2087isl_bool isl_mat_has_linearly_independent_rows(__isl_keep isl_mat *mat1,
2088	__isl_keep isl_mat *mat2)
2089{
2090	isl_size r1, r2, r;
2091	isl_mat *mat;
2092
2093	r1 = isl_mat_rank(mat1);
2094	if (r1 < 0)
2095		return isl_bool_error;
2096	if (r1 == 0)
2097		return isl_bool_true;
2098	r2 = isl_mat_rank(mat2);
2099	if (r2 < 0)
2100		return isl_bool_error;
2101	if (r2 == 0)
2102		return isl_bool_true;
2103
2104	mat = isl_mat_concat(isl_mat_copy(mat1), isl_mat_copy(mat2));
2105	r = isl_mat_rank(mat);
2106	isl_mat_free(mat);
2107	if (r < 0)
2108		return isl_bool_error;
2109	return isl_bool_ok(r == r1 + r2);
2110}
2111