4 #include "isl_map_private.h"
6 struct isl_mat *isl_mat_alloc(struct isl_ctx *ctx,
7 unsigned n_row, unsigned n_col)
12 mat = isl_alloc_type(ctx, struct isl_mat);
17 mat->block = isl_blk_alloc(ctx, n_row * n_col);
18 if (isl_blk_is_error(mat->block))
20 mat->row = isl_alloc_array(ctx, isl_int *, n_row);
24 for (i = 0; i < n_row; ++i)
25 mat->row[i] = mat->block.data + i * n_col;
37 isl_blk_free(ctx, mat->block);
42 struct isl_mat *isl_mat_extend(struct isl_mat *mat,
43 unsigned n_row, unsigned n_col)
51 if (mat->max_col >= n_col && mat->n_row >= n_row) {
52 if (mat->n_col < n_col)
57 if (mat->max_col < n_col) {
58 struct isl_mat *new_mat;
60 if (n_row < mat->n_row)
62 new_mat = isl_mat_alloc(mat->ctx, n_row, n_col);
65 for (i = 0; i < mat->n_row; ++i)
66 isl_seq_cpy(new_mat->row[i], mat->row[i], mat->n_col);
71 mat = isl_mat_cow(mat);
75 assert(mat->ref == 1);
76 old = mat->block.data;
77 mat->block = isl_blk_extend(mat->ctx, mat->block, n_row * mat->max_col);
78 if (isl_blk_is_error(mat->block))
80 mat->row = isl_realloc_array(mat->ctx, mat->row, isl_int *, n_row);
84 for (i = 0; i < mat->n_row; ++i)
85 mat->row[i] = mat->block.data + (mat->row[i] - old);
86 for (i = mat->n_row; i < n_row; ++i)
87 mat->row[i] = mat->block.data + i * mat->max_col;
89 if (mat->n_col < n_col)
98 struct isl_mat *isl_mat_sub_alloc(struct isl_ctx *ctx, isl_int **row,
99 unsigned first_row, unsigned n_row, unsigned first_col, unsigned n_col)
104 mat = isl_alloc_type(ctx, struct isl_mat);
107 mat->row = isl_alloc_array(ctx, isl_int *, n_row);
110 for (i = 0; i < n_row; ++i)
111 mat->row[i] = row[first_row+i] + first_col;
117 mat->block = isl_blk_empty();
118 mat->flags = ISL_MAT_BORROWED;
125 void isl_mat_sub_copy(struct isl_ctx *ctx, isl_int **dst, isl_int **src,
126 unsigned n_row, unsigned dst_col, unsigned src_col, unsigned n_col)
130 for (i = 0; i < n_row; ++i)
131 isl_seq_cpy(dst[i]+dst_col, src[i]+src_col, n_col);
134 void isl_mat_sub_neg(struct isl_ctx *ctx, isl_int **dst, isl_int **src,
135 unsigned n_row, unsigned dst_col, unsigned src_col, unsigned n_col)
139 for (i = 0; i < n_row; ++i)
140 isl_seq_neg(dst[i]+dst_col, src[i]+src_col, n_col);
143 struct isl_mat *isl_mat_copy(struct isl_mat *mat)
152 struct isl_mat *isl_mat_dup(struct isl_mat *mat)
155 struct isl_mat *mat2;
159 mat2 = isl_mat_alloc(mat->ctx, mat->n_row, mat->n_col);
162 for (i = 0; i < mat->n_row; ++i)
163 isl_seq_cpy(mat2->row[i], mat->row[i], mat->n_col);
167 struct isl_mat *isl_mat_cow(struct isl_mat *mat)
169 struct isl_mat *mat2;
173 if (mat->ref == 1 && !ISL_F_ISSET(mat, ISL_MAT_BORROWED))
176 mat2 = isl_mat_dup(mat);
181 void isl_mat_free(struct isl_mat *mat)
189 if (!ISL_F_ISSET(mat, ISL_MAT_BORROWED))
190 isl_blk_free(mat->ctx, mat->block);
191 isl_ctx_deref(mat->ctx);
196 struct isl_mat *isl_mat_identity(struct isl_ctx *ctx, unsigned n_row)
201 mat = isl_mat_alloc(ctx, n_row, n_row);
204 for (i = 0; i < n_row; ++i) {
205 isl_seq_clr(mat->row[i], i);
206 isl_int_set_si(mat->row[i][i], 1);
207 isl_seq_clr(mat->row[i]+i+1, n_row-(i+1));
213 struct isl_vec *isl_mat_vec_product(struct isl_mat *mat, struct isl_vec *vec)
216 struct isl_vec *prod;
221 isl_assert(ctx, mat->n_col == vec->size, goto error);
223 prod = isl_vec_alloc(mat->ctx, mat->n_row);
227 for (i = 0; i < prod->size; ++i)
228 isl_seq_inner_product(mat->row[i], vec->el, vec->size,
229 &prod->block.data[i]);
239 struct isl_mat *isl_mat_aff_direct_sum(struct isl_mat *left,
240 struct isl_mat *right)
248 isl_assert(ctx, left->n_row == right->n_row, goto error);
249 isl_assert(ctx, left->n_row >= 1, goto error);
250 isl_assert(ctx, left->n_col >= 1, goto error);
251 isl_assert(ctx, right->n_col >= 1, goto error);
253 isl_seq_first_non_zero(left->row[0]+1, left->n_col-1) == -1,
256 isl_seq_first_non_zero(right->row[0]+1, right->n_col-1) == -1,
259 sum = isl_mat_alloc(left->ctx, left->n_row, left->n_col + right->n_col - 1);
262 isl_int_lcm(sum->row[0][0], left->row[0][0], right->row[0][0]);
263 isl_int_divexact(left->row[0][0], sum->row[0][0], left->row[0][0]);
264 isl_int_divexact(right->row[0][0], sum->row[0][0], right->row[0][0]);
266 isl_seq_clr(sum->row[0]+1, sum->n_col-1);
267 for (i = 1; i < sum->n_row; ++i) {
268 isl_int_mul(sum->row[i][0], left->row[0][0], left->row[i][0]);
269 isl_int_addmul(sum->row[i][0],
270 right->row[0][0], right->row[i][0]);
271 isl_seq_scale(sum->row[i]+1, left->row[i]+1, left->row[0][0],
273 isl_seq_scale(sum->row[i]+left->n_col,
274 right->row[i]+1, right->row[0][0],
278 isl_int_divexact(left->row[0][0], sum->row[0][0], left->row[0][0]);
279 isl_int_divexact(right->row[0][0], sum->row[0][0], right->row[0][0]);
289 static void exchange(struct isl_mat *M, struct isl_mat **U,
290 struct isl_mat **Q, unsigned row, unsigned i, unsigned j)
293 for (r = row; r < M->n_row; ++r)
294 isl_int_swap(M->row[r][i], M->row[r][j]);
296 for (r = 0; r < (*U)->n_row; ++r)
297 isl_int_swap((*U)->row[r][i], (*U)->row[r][j]);
300 isl_mat_swap_rows(*Q, i, j);
303 static void subtract(struct isl_mat *M, struct isl_mat **U,
304 struct isl_mat **Q, unsigned row, unsigned i, unsigned j, isl_int m)
307 for (r = row; r < M->n_row; ++r)
308 isl_int_submul(M->row[r][j], m, M->row[r][i]);
310 for (r = 0; r < (*U)->n_row; ++r)
311 isl_int_submul((*U)->row[r][j], m, (*U)->row[r][i]);
314 for (r = 0; r < (*Q)->n_col; ++r)
315 isl_int_addmul((*Q)->row[i][r], m, (*Q)->row[j][r]);
319 static void oppose(struct isl_mat *M, struct isl_mat **U,
320 struct isl_mat **Q, unsigned row, unsigned col)
323 for (r = row; r < M->n_row; ++r)
324 isl_int_neg(M->row[r][col], M->row[r][col]);
326 for (r = 0; r < (*U)->n_row; ++r)
327 isl_int_neg((*U)->row[r][col], (*U)->row[r][col]);
330 isl_seq_neg((*Q)->row[col], (*Q)->row[col], (*Q)->n_col);
333 /* Given matrix M, compute
338 * with U and Q unimodular matrices and H a matrix in column echelon form
339 * such that on each echelon row the entries in the non-echelon column
340 * are non-negative (if neg == 0) or non-positive (if neg == 1)
341 * and stricly smaller (in absolute value) than the entries in the echelon
343 * If U or Q are NULL, then these matrices are not computed.
345 struct isl_mat *isl_mat_left_hermite(struct isl_mat *M, int neg,
346 struct isl_mat **U, struct isl_mat **Q)
361 *U = isl_mat_identity(M->ctx, M->n_col);
366 *Q = isl_mat_identity(M->ctx, M->n_col);
373 for (row = 0; row < M->n_row; ++row) {
375 first = isl_seq_abs_min_non_zero(M->row[row]+col, M->n_col-col);
380 exchange(M, U, Q, row, first, col);
381 if (isl_int_is_neg(M->row[row][col]))
382 oppose(M, U, Q, row, col);
384 while ((off = isl_seq_first_non_zero(M->row[row]+first,
385 M->n_col-first)) != -1) {
387 isl_int_fdiv_q(c, M->row[row][first], M->row[row][col]);
388 subtract(M, U, Q, row, col, first, c);
389 if (!isl_int_is_zero(M->row[row][first]))
390 exchange(M, U, Q, row, first, col);
394 for (i = 0; i < col; ++i) {
395 if (isl_int_is_zero(M->row[row][i]))
398 isl_int_cdiv_q(c, M->row[row][i], M->row[row][col]);
400 isl_int_fdiv_q(c, M->row[row][i], M->row[row][col]);
401 if (isl_int_is_zero(c))
403 subtract(M, U, Q, row, col, i, c);
422 struct isl_mat *isl_mat_right_kernel(struct isl_mat *mat)
425 struct isl_mat *U = NULL;
428 mat = isl_mat_left_hermite(mat, 0, &U, NULL);
432 for (i = 0, rank = 0; rank < mat->n_col; ++rank) {
433 while (i < mat->n_row && isl_int_is_zero(mat->row[i][rank]))
438 K = isl_mat_alloc(U->ctx, U->n_row, U->n_col - rank);
441 isl_mat_sub_copy(K->ctx, K->row, U->row, U->n_row, 0, rank, U->n_col-rank);
451 struct isl_mat *isl_mat_lin_to_aff(struct isl_mat *mat)
454 struct isl_mat *mat2;
458 mat2 = isl_mat_alloc(mat->ctx, 1+mat->n_row, 1+mat->n_col);
461 isl_int_set_si(mat2->row[0][0], 1);
462 isl_seq_clr(mat2->row[0]+1, mat->n_col);
463 for (i = 0; i < mat->n_row; ++i) {
464 isl_int_set_si(mat2->row[1+i][0], 0);
465 isl_seq_cpy(mat2->row[1+i]+1, mat->row[i], mat->n_col);
471 static int row_first_non_zero(isl_int **row, unsigned n_row, unsigned col)
475 for (i = 0; i < n_row; ++i)
476 if (!isl_int_is_zero(row[i][col]))
481 static int row_abs_min_non_zero(isl_int **row, unsigned n_row, unsigned col)
483 int i, min = row_first_non_zero(row, n_row, col);
486 for (i = min + 1; i < n_row; ++i) {
487 if (isl_int_is_zero(row[i][col]))
489 if (isl_int_abs_lt(row[i][col], row[min][col]))
495 static void inv_exchange(struct isl_mat *left, struct isl_mat *right,
496 unsigned i, unsigned j)
498 left = isl_mat_swap_rows(left, i, j);
499 right = isl_mat_swap_rows(right, i, j);
502 static void inv_oppose(
503 struct isl_mat *left, struct isl_mat *right, unsigned row)
505 isl_seq_neg(left->row[row]+row, left->row[row]+row, left->n_col-row);
506 isl_seq_neg(right->row[row], right->row[row], right->n_col);
509 static void inv_subtract(struct isl_mat *left, struct isl_mat *right,
510 unsigned row, unsigned i, isl_int m)
513 isl_seq_combine(left->row[i]+row,
514 left->ctx->one, left->row[i]+row,
515 m, left->row[row]+row,
517 isl_seq_combine(right->row[i], right->ctx->one, right->row[i],
518 m, right->row[row], right->n_col);
521 /* Compute inv(left)*right
523 struct isl_mat *isl_mat_inverse_product(struct isl_mat *left,
524 struct isl_mat *right)
532 isl_assert(left->ctx, left->n_row == left->n_col, goto error);
533 isl_assert(left->ctx, left->n_row == right->n_row, goto error);
535 if (left->n_row == 0) {
540 left = isl_mat_cow(left);
541 right = isl_mat_cow(right);
547 for (row = 0; row < left->n_row; ++row) {
548 int pivot, first, i, off;
549 pivot = row_abs_min_non_zero(left->row+row, left->n_row-row, row);
553 isl_assert(ctx, pivot >= 0, goto error);
557 inv_exchange(left, right, pivot, row);
558 if (isl_int_is_neg(left->row[row][row]))
559 inv_oppose(left, right, row);
561 while ((off = row_first_non_zero(left->row+first,
562 left->n_row-first, row)) != -1) {
564 isl_int_fdiv_q(a, left->row[first][row],
565 left->row[row][row]);
566 inv_subtract(left, right, row, first, a);
567 if (!isl_int_is_zero(left->row[first][row]))
568 inv_exchange(left, right, row, first);
572 for (i = 0; i < row; ++i) {
573 if (isl_int_is_zero(left->row[i][row]))
575 isl_int_gcd(a, left->row[row][row], left->row[i][row]);
576 isl_int_divexact(b, left->row[i][row], a);
577 isl_int_divexact(a, left->row[row][row], a);
579 isl_seq_combine(left->row[i]+row,
581 b, left->row[row]+row,
583 isl_seq_combine(right->row[i], a, right->row[i],
584 b, right->row[row], right->n_col);
589 isl_int_set(a, left->row[0][0]);
590 for (row = 1; row < left->n_row; ++row)
591 isl_int_lcm(a, a, left->row[row][row]);
592 if (isl_int_is_zero(a)){
594 isl_assert(ctx, 0, goto error);
596 for (row = 0; row < left->n_row; ++row) {
597 isl_int_divexact(left->row[row][row], a, left->row[row][row]);
598 if (isl_int_is_one(left->row[row][row]))
600 isl_seq_scale(right->row[row], right->row[row],
601 left->row[row][row], right->n_col);
613 void isl_mat_col_scale(struct isl_mat *mat, unsigned col, isl_int m)
617 for (i = 0; i < mat->n_row; ++i)
618 isl_int_mul(mat->row[i][col], mat->row[i][col], m);
621 void isl_mat_col_combine(struct isl_mat *mat, unsigned dst,
622 isl_int m1, unsigned src1, isl_int m2, unsigned src2)
628 for (i = 0; i < mat->n_row; ++i) {
629 isl_int_mul(tmp, m1, mat->row[i][src1]);
630 isl_int_addmul(tmp, m2, mat->row[i][src2]);
631 isl_int_set(mat->row[i][dst], tmp);
636 struct isl_mat *isl_mat_right_inverse(struct isl_mat *mat)
642 mat = isl_mat_cow(mat);
646 inv = isl_mat_identity(mat->ctx, mat->n_col);
647 inv = isl_mat_cow(inv);
653 for (row = 0; row < mat->n_row; ++row) {
654 int pivot, first, i, off;
655 pivot = isl_seq_abs_min_non_zero(mat->row[row]+row, mat->n_col-row);
663 exchange(mat, &inv, NULL, row, pivot, row);
664 if (isl_int_is_neg(mat->row[row][row]))
665 oppose(mat, &inv, NULL, row, row);
667 while ((off = isl_seq_first_non_zero(mat->row[row]+first,
668 mat->n_col-first)) != -1) {
670 isl_int_fdiv_q(a, mat->row[row][first],
672 subtract(mat, &inv, NULL, row, row, first, a);
673 if (!isl_int_is_zero(mat->row[row][first]))
674 exchange(mat, &inv, NULL, row, row, first);
678 for (i = 0; i < row; ++i) {
679 if (isl_int_is_zero(mat->row[row][i]))
681 isl_int_gcd(a, mat->row[row][row], mat->row[row][i]);
682 isl_int_divexact(b, mat->row[row][i], a);
683 isl_int_divexact(a, mat->row[row][row], a);
685 isl_mat_col_combine(mat, i, a, i, b, row);
686 isl_mat_col_combine(inv, i, a, i, b, row);
691 isl_int_set(a, mat->row[0][0]);
692 for (row = 1; row < mat->n_row; ++row)
693 isl_int_lcm(a, a, mat->row[row][row]);
694 if (isl_int_is_zero(a)){
698 for (row = 0; row < mat->n_row; ++row) {
699 isl_int_divexact(mat->row[row][row], a, mat->row[row][row]);
700 if (isl_int_is_one(mat->row[row][row]))
702 isl_mat_col_scale(inv, row, mat->row[row][row]);
714 struct isl_mat *isl_mat_transpose(struct isl_mat *mat)
716 struct isl_mat *transpose = NULL;
719 if (mat->n_col == mat->n_row) {
720 mat = isl_mat_cow(mat);
723 for (i = 0; i < mat->n_row; ++i)
724 for (j = i + 1; j < mat->n_col; ++j)
725 isl_int_swap(mat->row[i][j], mat->row[j][i]);
728 transpose = isl_mat_alloc(mat->ctx, mat->n_col, mat->n_row);
731 for (i = 0; i < mat->n_row; ++i)
732 for (j = 0; j < mat->n_col; ++j)
733 isl_int_set(transpose->row[j][i], mat->row[i][j]);
741 struct isl_mat *isl_mat_swap_cols(struct isl_mat *mat, unsigned i, unsigned j)
745 mat = isl_mat_cow(mat);
748 isl_assert(ctx, i < mat->n_col, goto error);
749 isl_assert(ctx, j < mat->n_col, goto error);
751 for (r = 0; r < mat->n_row; ++r)
752 isl_int_swap(mat->row[r][i], mat->row[r][j]);
759 struct isl_mat *isl_mat_swap_rows(struct isl_mat *mat, unsigned i, unsigned j)
765 mat = isl_mat_cow(mat);
769 mat->row[i] = mat->row[j];
774 struct isl_mat *isl_mat_product(struct isl_mat *left, struct isl_mat *right)
777 struct isl_mat *prod;
781 isl_assert(ctx, left->n_col == right->n_row, goto error);
782 prod = isl_mat_alloc(left->ctx, left->n_row, right->n_col);
785 if (left->n_col == 0) {
786 for (i = 0; i < prod->n_row; ++i)
787 isl_seq_clr(prod->row[i], prod->n_col);
790 for (i = 0; i < prod->n_row; ++i) {
791 for (j = 0; j < prod->n_col; ++j) {
792 isl_int_mul(prod->row[i][j],
793 left->row[i][0], right->row[0][j]);
794 for (k = 1; k < left->n_col; ++k)
795 isl_int_addmul(prod->row[i][j],
796 left->row[i][k], right->row[k][j]);
808 /* Replace the variables x in the rows q by x' given by x = M x',
809 * with M the matrix mat.
811 * If the number of new variables is greater than the original
812 * number of variables, then the rows q have already been
813 * preextended. If the new number is smaller, then the coefficients
814 * of the divs, which are not changed, need to be shifted down.
815 * The row q may be the equalities, the inequalities or the
816 * div expressions. In the latter case, has_div is true and
817 * we need to take into account the extra denominator column.
819 static int preimage(struct isl_ctx *ctx, isl_int **q, unsigned n,
820 unsigned n_div, int has_div, struct isl_mat *mat)
826 if (mat->n_col >= mat->n_row)
829 e = mat->n_row - mat->n_col;
831 for (i = 0; i < n; ++i)
832 isl_int_mul(q[i][0], q[i][0], mat->row[0][0]);
833 t = isl_mat_sub_alloc(mat->ctx, q, 0, n, has_div, mat->n_row);
834 t = isl_mat_product(t, mat);
837 for (i = 0; i < n; ++i) {
838 isl_seq_swp_or_cpy(q[i] + has_div, t->row[i], t->n_col);
839 isl_seq_cpy(q[i] + has_div + t->n_col,
840 q[i] + has_div + t->n_col + e, n_div);
841 isl_seq_clr(q[i] + has_div + t->n_col + n_div, e);
847 /* Replace the variables x in bset by x' given by x = M x', with
850 * If there are fewer variables x' then there are x, then we perform
851 * the transformation in place, which that, in principle,
852 * this frees up some extra variables as the number
853 * of columns remains constant, but we would have to extend
854 * the div array too as the number of rows in this array is assumed
855 * to be equal to extra.
857 struct isl_basic_set *isl_basic_set_preimage(struct isl_basic_set *bset,
866 bset = isl_basic_set_cow(bset);
870 isl_assert(ctx, bset->dim->nparam == 0, goto error);
871 isl_assert(ctx, 1+bset->dim->n_out == mat->n_row, goto error);
873 if (mat->n_col > mat->n_row)
874 bset = isl_basic_set_extend(bset, 0, mat->n_col-1, 0,
876 else if (mat->n_col < mat->n_row) {
877 bset->dim = isl_dim_cow(bset->dim);
880 bset->dim->n_out -= mat->n_row - mat->n_col;
883 if (preimage(ctx, bset->eq, bset->n_eq, bset->n_div, 0,
884 isl_mat_copy(mat)) < 0)
887 if (preimage(ctx, bset->ineq, bset->n_ineq, bset->n_div, 0,
888 isl_mat_copy(mat)) < 0)
891 if (preimage(ctx, bset->div, bset->n_div, bset->n_div, 1, mat) < 0)
894 ISL_F_CLR(bset, ISL_BASIC_SET_NO_IMPLICIT);
895 ISL_F_CLR(bset, ISL_BASIC_SET_NO_REDUNDANT);
896 ISL_F_CLR(bset, ISL_BASIC_SET_NORMALIZED);
897 ISL_F_CLR(bset, ISL_BASIC_SET_NORMALIZED_DIVS);
898 ISL_F_CLR(bset, ISL_BASIC_SET_ALL_EQUALITIES);
900 bset = isl_basic_set_simplify(bset);
901 bset = isl_basic_set_finalize(bset);
907 isl_basic_set_free(bset);
911 struct isl_set *isl_set_preimage(struct isl_set *set, struct isl_mat *mat)
916 set = isl_set_cow(set);
921 for (i = 0; i < set->n; ++i) {
922 set->p[i] = isl_basic_set_preimage(set->p[i],
927 if (mat->n_col != mat->n_row) {
928 set->dim = isl_dim_cow(set->dim);
931 set->dim->n_out += mat->n_col;
932 set->dim->n_out -= mat->n_row;
935 ISL_F_CLR(set, ISL_SET_NORMALIZED);
943 void isl_mat_dump(struct isl_mat *mat, FILE *out, int indent)
948 fprintf(out, "%*snull mat\n", indent, "");
953 fprintf(out, "%*s[]\n", indent, "");
955 for (i = 0; i < mat->n_row; ++i) {
957 fprintf(out, "%*s[[", indent, "");
959 fprintf(out, "%*s[", indent+1, "");
960 for (j = 0; j < mat->n_col; ++j) {
963 isl_int_print(out, mat->row[i][j], 0);
965 if (i == mat->n_row-1)
966 fprintf(out, "]]\n");
972 struct isl_mat *isl_mat_drop_cols(struct isl_mat *mat, unsigned col, unsigned n)
976 mat = isl_mat_cow(mat);
980 if (col != mat->n_col-n) {
981 for (r = 0; r < mat->n_row; ++r)
982 isl_seq_cpy(mat->row[r]+col, mat->row[r]+col+n,
983 mat->n_col - col - n);
989 struct isl_mat *isl_mat_drop_rows(struct isl_mat *mat, unsigned row, unsigned n)
993 mat = isl_mat_cow(mat);
997 for (r = row; r+n < mat->n_row; ++r)
998 mat->row[r] = mat->row[r+n];
1004 void isl_mat_col_submul(struct isl_mat *mat,
1005 int dst_col, isl_int f, int src_col)
1009 for (i = 0; i < mat->n_row; ++i)
1010 isl_int_submul(mat->row[i][dst_col], f, mat->row[i][src_col]);
1013 void isl_mat_col_mul(struct isl_mat *mat, int dst_col, isl_int f, int src_col)
1017 for (i = 0; i < mat->n_row; ++i)
1018 isl_int_mul(mat->row[i][dst_col], f, mat->row[i][src_col]);
1021 struct isl_mat *isl_mat_unimodular_complete(struct isl_mat *M, int row)
1024 struct isl_mat *H = NULL, *Q = NULL;
1026 isl_assert(ctx, M->n_row == M->n_col, goto error);
1028 H = isl_mat_left_hermite(isl_mat_copy(M), 0, NULL, &Q);
1029 M->n_row = M->n_col;
1032 for (r = 0; r < row; ++r)
1033 isl_assert(ctx, isl_int_is_one(H->row[r][r]), goto error);
1034 for (r = row; r < M->n_row; ++r)
1035 isl_seq_cpy(M->row[r], Q->row[r], M->n_col);