57 lines
1.8 KiB
C
57 lines
1.8 KiB
C
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/*=============================================================================
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This file is part of FLINT.
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FLINT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FLINT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2011 Fredrik Johansson
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******************************************************************************/
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#include "flint.h"
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#include "nmod_poly.h"
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#include "nmod_poly_mat.h"
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slong
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nmod_poly_mat_find_pivot_partial(const nmod_poly_mat_t mat,
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slong start_row, slong end_row, slong c)
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{
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slong best_row, best_length, i;
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best_row = start_row;
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best_length = nmod_poly_length(nmod_poly_mat_entry(mat, start_row, c));
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for (i = start_row + 1; i < end_row; i++)
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{
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slong l;
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l = nmod_poly_length(nmod_poly_mat_entry(mat, i, c));
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if (l != 0 && (best_length == 0 || l <= best_length))
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{
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best_row = i;
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best_length = l;
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}
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}
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if (best_length == 0)
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return -1;
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return best_row;
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}
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