1 /*
2 * Copyright (c) 2011, Michael Lehn
3 *
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1) Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2) Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
15 * distribution.
16 * 3) Neither the name of the FLENS development group nor the names of
17 * its contributors may be used to endorse or promote products derived
18 * from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 /* Based on
34 *
35 SUBROUTINE DLADIV( A, B, C, D, P, Q )
36 *
37 * -- LAPACK auxiliary routine (version 3.2) --
38 * -- LAPACK is a software package provided by Univ. of Tennessee, --
39 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
40 * November 2006
41 */
42
43 #ifndef FLENS_LAPACK_AUX_LADIV_TCC
44 #define FLENS_LAPACK_AUX_LADIV_TCC 1
45
46 #include <cmath>
47
48 namespace flens { namespace lapack {
49
50 //== generic lapack implementation =============================================
51 template <typename T>
52 void
53 ladiv(const T &a, const T &b, const T &c, const T &d, T &p, T &q)
54 {
55 LAPACK_DEBUG_OUT("ladiv");
56
57 using std::abs;
58
59 if (abs(d)<abs(c)) {
60 const T e = d / c;
61 const T f = c + d*e;
62 p = (a + b*e) / f;
63 q = (b - a*e) / f;
64 } else {
65 const T e = c / d;
66 const T f = d + c*e;
67 p = ( b + a*e) / f;
68 q = (-a + b*e) / f;
69 }
70 }
71
72 } } // namespace lapack, flens
73
74 #endif // FLENS_LAPACK_AUX_LADIV_TCC
2 * Copyright (c) 2011, Michael Lehn
3 *
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1) Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2) Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
15 * distribution.
16 * 3) Neither the name of the FLENS development group nor the names of
17 * its contributors may be used to endorse or promote products derived
18 * from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 /* Based on
34 *
35 SUBROUTINE DLADIV( A, B, C, D, P, Q )
36 *
37 * -- LAPACK auxiliary routine (version 3.2) --
38 * -- LAPACK is a software package provided by Univ. of Tennessee, --
39 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
40 * November 2006
41 */
42
43 #ifndef FLENS_LAPACK_AUX_LADIV_TCC
44 #define FLENS_LAPACK_AUX_LADIV_TCC 1
45
46 #include <cmath>
47
48 namespace flens { namespace lapack {
49
50 //== generic lapack implementation =============================================
51 template <typename T>
52 void
53 ladiv(const T &a, const T &b, const T &c, const T &d, T &p, T &q)
54 {
55 LAPACK_DEBUG_OUT("ladiv");
56
57 using std::abs;
58
59 if (abs(d)<abs(c)) {
60 const T e = d / c;
61 const T f = c + d*e;
62 p = (a + b*e) / f;
63 q = (b - a*e) / f;
64 } else {
65 const T e = c / d;
66 const T f = d + c*e;
67 p = ( b + a*e) / f;
68 q = (-a + b*e) / f;
69 }
70 }
71
72 } } // namespace lapack, flens
73
74 #endif // FLENS_LAPACK_AUX_LADIV_TCC