template_blas_rot.h

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00001 /* Ergo, version 3.2, a program for linear scaling electronic structure
00002  * calculations.
00003  * Copyright (C) 2012 Elias Rudberg, Emanuel H. Rubensson, and Pawel Salek.
00004  * 
00005  * This program is free software: you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License as published by
00007  * the Free Software Foundation, either version 3 of the License, or
00008  * (at your option) any later version.
00009  * 
00010  * This program is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013  * GNU General Public License for more details.
00014  * 
00015  * You should have received a copy of the GNU General Public License
00016  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
00017  * 
00018  * Primary academic reference:
00019  * Kohn−Sham Density Functional Theory Electronic Structure Calculations 
00020  * with Linearly Scaling Computational Time and Memory Usage,
00021  * Elias Rudberg, Emanuel H. Rubensson, and Pawel Salek,
00022  * J. Chem. Theory Comput. 7, 340 (2011),
00023  * <http://dx.doi.org/10.1021/ct100611z>
00024  * 
00025  * For further information about Ergo, see <http://www.ergoscf.org>.
00026  */
00027  
00028  /* This file belongs to the template_lapack part of the Ergo source 
00029   * code. The source files in the template_lapack directory are modified
00030   * versions of files originally distributed as CLAPACK, see the
00031   * Copyright/license notice in the file template_lapack/COPYING.
00032   */
00033  
00034 
00035 #ifndef TEMPLATE_BLAS_ROT_HEADER
00036 #define TEMPLATE_BLAS_ROT_HEADER
00037 
00038 
00039 template<class Treal>
00040 int template_blas_rot(const integer *n, Treal *dx, const integer *incx, 
00041         Treal *dy, const integer *incy, const Treal *c__, const Treal *s)
00042 {
00043     /* System generated locals */
00044     integer i__1;
00045     /* Local variables */
00046      integer i__;
00047      Treal dtemp;
00048      integer ix, iy;
00049 /*     applies a plane rotation.   
00050        jack dongarra, linpack, 3/11/78.   
00051        modified 12/3/93, array(1) declarations changed to array(*)   
00052        Parameter adjustments */
00053     --dy;
00054     --dx;
00055     /* Function Body */
00056     if (*n <= 0) {
00057         return 0;
00058     }
00059     if (*incx == 1 && *incy == 1) {
00060         goto L20;
00061     }
00062 /*       code for unequal increments or equal increments not equal   
00063            to 1 */
00064     ix = 1;
00065     iy = 1;
00066     if (*incx < 0) {
00067         ix = (-(*n) + 1) * *incx + 1;
00068     }
00069     if (*incy < 0) {
00070         iy = (-(*n) + 1) * *incy + 1;
00071     }
00072     i__1 = *n;
00073     for (i__ = 1; i__ <= i__1; ++i__) {
00074         dtemp = *c__ * dx[ix] + *s * dy[iy];
00075         dy[iy] = *c__ * dy[iy] - *s * dx[ix];
00076         dx[ix] = dtemp;
00077         ix += *incx;
00078         iy += *incy;
00079 /* L10: */
00080     }
00081     return 0;
00082 /*       code for both increments equal to 1 */
00083 L20:
00084     i__1 = *n;
00085     for (i__ = 1; i__ <= i__1; ++i__) {
00086         dtemp = *c__ * dx[i__] + *s * dy[i__];
00087         dy[i__] = *c__ * dy[i__] - *s * dx[i__];
00088         dx[i__] = dtemp;
00089 /* L30: */
00090     }
00091     return 0;
00092 } /* drot_ */
00093 
00094 #endif

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