template_blas_scal.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_SCAL_HEADER
00036 #define TEMPLATE_BLAS_SCAL_HEADER
00037 
00038 #include "template_blas_common.h"
00039 
00040 template<class Treal>
00041 int template_blas_scal(const integer *n, const Treal *da, Treal *dx, 
00042         const integer *incx)
00043 {
00044     /* System generated locals */
00045     integer i__1, i__2;
00046     /* Local variables */
00047      integer i__, m, nincx, mp1;
00048 /*     scales a vector by a constant.   
00049        uses unrolled loops for increment equal to one.   
00050        jack dongarra, linpack, 3/11/78.   
00051        modified 3/93 to return if incx .le. 0.   
00052        modified 12/3/93, array(1) declarations changed to array(*)   
00053        Parameter adjustments */
00054     --dx;
00055     /* Function Body */
00056     if (*n <= 0 || *incx <= 0) {
00057         return 0;
00058     }
00059     if (*incx == 1) {
00060         goto L20;
00061     }
00062 /*        code for increment not equal to 1 */
00063     nincx = *n * *incx;
00064     i__1 = nincx;
00065     i__2 = *incx;
00066     for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
00067         dx[i__] = *da * dx[i__];
00068 /* L10: */
00069     }
00070     return 0;
00071 /*        code for increment equal to 1   
00072           clean-up loop */
00073 L20:
00074     m = *n % 5;
00075     if (m == 0) {
00076         goto L40;
00077     }
00078     i__2 = m;
00079     for (i__ = 1; i__ <= i__2; ++i__) {
00080         dx[i__] = *da * dx[i__];
00081 /* L30: */
00082     }
00083     if (*n < 5) {
00084         return 0;
00085     }
00086 L40:
00087     mp1 = m + 1;
00088     i__2 = *n;
00089     for (i__ = mp1; i__ <= i__2; i__ += 5) {
00090         dx[i__] = *da * dx[i__];
00091         dx[i__ + 1] = *da * dx[i__ + 1];
00092         dx[i__ + 2] = *da * dx[i__ + 2];
00093         dx[i__ + 3] = *da * dx[i__ + 3];
00094         dx[i__ + 4] = *da * dx[i__ + 4];
00095 /* L50: */
00096     }
00097     return 0;
00098 } /* dscal_ */
00099 
00100 #endif

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