ergo
template_blas_dot.h
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1/* Ergo, version 3.8.2, a program for linear scaling electronic structure
2 * calculations.
3 * Copyright (C) 2023 Elias Rudberg, Emanuel H. Rubensson, Pawel Salek,
4 * and Anastasia Kruchinina.
5 *
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 *
19 * Primary academic reference:
20 * Ergo: An open-source program for linear-scaling electronic structure
21 * calculations,
22 * Elias Rudberg, Emanuel H. Rubensson, Pawel Salek, and Anastasia
23 * Kruchinina,
24 * SoftwareX 7, 107 (2018),
25 * <http://dx.doi.org/10.1016/j.softx.2018.03.005>
26 *
27 * For further information about Ergo, see <http://www.ergoscf.org>.
28 */
29
30 /* This file belongs to the template_lapack part of the Ergo source
31 * code. The source files in the template_lapack directory are modified
32 * versions of files originally distributed as CLAPACK, see the
33 * Copyright/license notice in the file template_lapack/COPYING.
34 */
35
36
37#ifndef TEMPLATE_BLAS_DOT_HEADER
38#define TEMPLATE_BLAS_DOT_HEADER
39
41
42template<class Treal>
43Treal template_blas_dot(const integer *n, const Treal *dx, const integer *incx, const Treal *dy,
44 const integer *incy)
45{
46 /* System generated locals */
47 integer i__1;
48 Treal ret_val;
49 /* Local variables */
50 integer i__, m;
51 Treal dtemp;
52 integer ix, iy, mp1;
53/* forms the dot product of two vectors.
54 uses unrolled loops for increments equal to one.
55 jack dongarra, linpack, 3/11/78.
56 modified 12/3/93, array(1) declarations changed to array(*)
57 Parameter adjustments */
58 --dy;
59 --dx;
60 /* Function Body */
61 ret_val = 0.;
62 dtemp = 0.;
63 if (*n <= 0) {
64 return ret_val;
65 }
66 if (*incx == 1 && *incy == 1) {
67 goto L20;
68 }
69/* code for unequal increments or equal increments
70 not equal to 1 */
71 ix = 1;
72 iy = 1;
73 if (*incx < 0) {
74 ix = (-(*n) + 1) * *incx + 1;
75 }
76 if (*incy < 0) {
77 iy = (-(*n) + 1) * *incy + 1;
78 }
79 i__1 = *n;
80 for (i__ = 1; i__ <= i__1; ++i__) {
81 dtemp += dx[ix] * dy[iy];
82 ix += *incx;
83 iy += *incy;
84/* L10: */
85 }
86 ret_val = dtemp;
87 return ret_val;
88/* code for both increments equal to 1
89 clean-up loop */
90L20:
91 m = *n % 5;
92 if (m == 0) {
93 goto L40;
94 }
95 i__1 = m;
96 for (i__ = 1; i__ <= i__1; ++i__) {
97 dtemp += dx[i__] * dy[i__];
98/* L30: */
99 }
100 if (*n < 5) {
101 goto L60;
102 }
103L40:
104 mp1 = m + 1;
105 i__1 = *n;
106 for (i__ = mp1; i__ <= i__1; i__ += 5) {
107 dtemp = dtemp + dx[i__] * dy[i__] + dx[i__ + 1] * dy[i__ + 1] + dx[
108 i__ + 2] * dy[i__ + 2] + dx[i__ + 3] * dy[i__ + 3] + dx[i__ +
109 4] * dy[i__ + 4];
110/* L50: */
111 }
112L60:
113 ret_val = dtemp;
114 return ret_val;
115} /* ddot_ */
116
117#endif
int integer
Definition: template_blas_common.h:40
Treal template_blas_dot(const integer *n, const Treal *dx, const integer *incx, const Treal *dy, const integer *incy)
Definition: template_blas_dot.h:43