ergo
template_blas_swap.h
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1/* Ergo, version 3.8, a program for linear scaling electronic structure
2 * calculations.
3 * Copyright (C) 2019 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_SWAP_HEADER
38#define TEMPLATE_BLAS_SWAP_HEADER
39
40
41template<class Treal>
42int template_blas_swap(const integer *n, Treal *dx, const integer *incx,
43 Treal *dy, const integer *incy)
44{
45 /* System generated locals */
46 integer i__1;
47 /* Local variables */
48 integer i__, m;
49 Treal dtemp;
50 integer ix, iy, mp1;
51/* interchanges two vectors.
52 uses unrolled loops for increments equal one.
53 jack dongarra, linpack, 3/11/78.
54 modified 12/3/93, array(1) declarations changed to array(*)
55 Parameter adjustments */
56 --dy;
57 --dx;
58 /* Function Body */
59 if (*n <= 0) {
60 return 0;
61 }
62 if (*incx == 1 && *incy == 1) {
63 goto L20;
64 }
65/* code for unequal increments or equal increments not equal
66 to 1 */
67 ix = 1;
68 iy = 1;
69 if (*incx < 0) {
70 ix = (-(*n) + 1) * *incx + 1;
71 }
72 if (*incy < 0) {
73 iy = (-(*n) + 1) * *incy + 1;
74 }
75 i__1 = *n;
76 for (i__ = 1; i__ <= i__1; ++i__) {
77 dtemp = dx[ix];
78 dx[ix] = dy[iy];
79 dy[iy] = dtemp;
80 ix += *incx;
81 iy += *incy;
82/* L10: */
83 }
84 return 0;
85/* code for both increments equal to 1
86 clean-up loop */
87L20:
88 m = *n % 3;
89 if (m == 0) {
90 goto L40;
91 }
92 i__1 = m;
93 for (i__ = 1; i__ <= i__1; ++i__) {
94 dtemp = dx[i__];
95 dx[i__] = dy[i__];
96 dy[i__] = dtemp;
97/* L30: */
98 }
99 if (*n < 3) {
100 return 0;
101 }
102L40:
103 mp1 = m + 1;
104 i__1 = *n;
105 for (i__ = mp1; i__ <= i__1; i__ += 3) {
106 dtemp = dx[i__];
107 dx[i__] = dy[i__];
108 dy[i__] = dtemp;
109 dtemp = dx[i__ + 1];
110 dx[i__ + 1] = dy[i__ + 1];
111 dy[i__ + 1] = dtemp;
112 dtemp = dx[i__ + 2];
113 dx[i__ + 2] = dy[i__ + 2];
114 dy[i__ + 2] = dtemp;
115/* L50: */
116 }
117 return 0;
118} /* dswap_ */
119
120#endif
int integer
Definition: template_blas_common.h:40
int template_blas_swap(const integer *n, Treal *dx, const integer *incx, Treal *dy, const integer *incy)
Definition: template_blas_swap.h:42