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/* blas/source_nrm2_c.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 < 1) {
return 0;
}
for (i = 0; i < N; i++) {
const BASE x = CONST_REAL(X, ix);
const BASE y = CONST_IMAG(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);
}
}
if (y != 0.0) {
const BASE ay = fabs(y);
if (scale < ay) {
ssq = 1.0 + ssq * (scale / ay) * (scale / ay);
scale = ay;
} else {
ssq += (ay / scale) * (ay / scale);
}
}
ix += incX;
}
return scale * sqrt(ssq);
}
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