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Diffstat (limited to 'gsl-1.9/poly/companion.c')
-rw-r--r-- | gsl-1.9/poly/companion.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/gsl-1.9/poly/companion.c b/gsl-1.9/poly/companion.c new file mode 100644 index 0000000..736483f --- /dev/null +++ b/gsl-1.9/poly/companion.c @@ -0,0 +1,36 @@ +/* poly/companion.c + * + * Copyright (C) 1996, 1997, 1998, 1999, 2000 Brian Gough + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +static void set_companion_matrix (const double *a, size_t n, double *m); + +static void +set_companion_matrix (const double *a, size_t nc, double *m) +{ + size_t i, j; + + for (i = 0; i < nc; i++) + for (j = 0; j < nc; j++) + MAT (m, i, j, nc) = 0.0; + + for (i = 1; i < nc; i++) + MAT (m, i, i - 1, nc) = 1.0; + + for (i = 0; i < nc; i++) + MAT (m, i, nc - 1, nc) = -a[i] / a[nc]; +} |