diff options
Diffstat (limited to 'gsl-1.9/cblas/source_nrm2_r.h')
-rw-r--r-- | gsl-1.9/cblas/source_nrm2_r.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/gsl-1.9/cblas/source_nrm2_r.h b/gsl-1.9/cblas/source_nrm2_r.h new file mode 100644 index 0000000..d2beb3a --- /dev/null +++ b/gsl-1.9/cblas/source_nrm2_r.h @@ -0,0 +1,50 @@ +/* blas/source_nrm2_r.h + * + * Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman + * + * 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. + */ + +{ + BASE scale = 0.0; + BASE ssq = 1.0; + INDEX i; + INDEX ix = 0; + + if (N <= 0 || incX <= 0) { + return 0; + } else if (N == 1) { + return fabs(X[0]); + } + + for (i = 0; i < N; i++) { + const BASE x = X[ix]; + + if (x != 0.0) { + const BASE ax = fabs(x); + + if (scale < ax) { + ssq = 1.0 + ssq * (scale / ax) * (scale / ax); + scale = ax; + } else { + ssq += (ax / scale) * (ax / scale); + } + } + + ix += incX; + } + + return scale * sqrt(ssq); +} |