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https://github.com/VK3FNG/soundmodem.git
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73 lines
1.6 KiB
C
73 lines
1.6 KiB
C
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/*
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* Matrix operations library
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*
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* Copyright (C) 1999-2000
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* Thomas Sailer, <sailer@ife.ee.ethz.ch>
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*
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* This program 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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*
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* This program 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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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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/* AIX requires this to be the first thing in the file. */
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#ifndef __GNUC__
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# if HAVE_ALLOCA_H
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# include <alloca.h>
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# else
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# ifdef _AIX
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#pragma alloca
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# else
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# ifndef alloca /* predefined by HP cc +Olibcalls */
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char *alloca ();
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# endif
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# endif
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# endif
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#endif
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#include "mat.h"
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float frdet(const float *c, unsigned int d)
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{
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float *c2;
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unsigned int i, j, k, l;
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float det = 0, dr;
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if (!d)
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return 0;
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if (d == 1)
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return c[0];
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if (d == 2)
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return c[0] * c[3] - c[1] * c[2];
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c2 = alloca(sizeof(float)*(d-1)*(d-1));
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for (i = 0; i < d; i++) {
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for (j = k = 0; j < d; j++) {
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if (j == i)
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continue;
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for (l = 0; l < d-1; l++)
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c2[l*(d-1)+k] = c[(l+1)*d+j];
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k++;
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}
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dr = frdet(c2, d-1);
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if (i & 1)
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det -= dr * c[i];
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else
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det += dr * c[i];
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}
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return det;
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}
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