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- /* 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 3 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);
- }
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