[136] | 1 | *> \brief \b SLADIV
|
---|
| 2 | *
|
---|
| 3 | * =========== DOCUMENTATION ===========
|
---|
| 4 | *
|
---|
| 5 | * Online html documentation available at
|
---|
| 6 | * http://www.netlib.org/lapack/explore-html/
|
---|
| 7 | *
|
---|
| 8 | *> \htmlonly
|
---|
| 9 | *> Download SLADIV + dependencies
|
---|
| 10 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/sladiv.f">
|
---|
| 11 | *> [TGZ]</a>
|
---|
| 12 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/sladiv.f">
|
---|
| 13 | *> [ZIP]</a>
|
---|
| 14 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/sladiv.f">
|
---|
| 15 | *> [TXT]</a>
|
---|
| 16 | *> \endhtmlonly
|
---|
| 17 | *
|
---|
| 18 | * Definition:
|
---|
| 19 | * ===========
|
---|
| 20 | *
|
---|
| 21 | * SUBROUTINE SLADIV( A, B, C, D, P, Q )
|
---|
| 22 | *
|
---|
| 23 | * .. Scalar Arguments ..
|
---|
| 24 | * REAL A, B, C, D, P, Q
|
---|
| 25 | * ..
|
---|
| 26 | *
|
---|
| 27 | *
|
---|
| 28 | *> \par Purpose:
|
---|
| 29 | * =============
|
---|
| 30 | *>
|
---|
| 31 | *> \verbatim
|
---|
| 32 | *>
|
---|
| 33 | *> SLADIV performs complex division in real arithmetic
|
---|
| 34 | *>
|
---|
| 35 | *> a + i*b
|
---|
| 36 | *> p + i*q = ---------
|
---|
| 37 | *> c + i*d
|
---|
| 38 | *>
|
---|
| 39 | *> The algorithm is due to Robert L. Smith and can be found
|
---|
| 40 | *> in D. Knuth, The art of Computer Programming, Vol.2, p.195
|
---|
| 41 | *> \endverbatim
|
---|
| 42 | *
|
---|
| 43 | * Arguments:
|
---|
| 44 | * ==========
|
---|
| 45 | *
|
---|
| 46 | *> \param[in] A
|
---|
| 47 | *> \verbatim
|
---|
| 48 | *> A is REAL
|
---|
| 49 | *> \endverbatim
|
---|
| 50 | *>
|
---|
| 51 | *> \param[in] B
|
---|
| 52 | *> \verbatim
|
---|
| 53 | *> B is REAL
|
---|
| 54 | *> \endverbatim
|
---|
| 55 | *>
|
---|
| 56 | *> \param[in] C
|
---|
| 57 | *> \verbatim
|
---|
| 58 | *> C is REAL
|
---|
| 59 | *> \endverbatim
|
---|
| 60 | *>
|
---|
| 61 | *> \param[in] D
|
---|
| 62 | *> \verbatim
|
---|
| 63 | *> D is REAL
|
---|
| 64 | *> The scalars a, b, c, and d in the above expression.
|
---|
| 65 | *> \endverbatim
|
---|
| 66 | *>
|
---|
| 67 | *> \param[out] P
|
---|
| 68 | *> \verbatim
|
---|
| 69 | *> P is REAL
|
---|
| 70 | *> \endverbatim
|
---|
| 71 | *>
|
---|
| 72 | *> \param[out] Q
|
---|
| 73 | *> \verbatim
|
---|
| 74 | *> Q is REAL
|
---|
| 75 | *> The scalars p and q in the above expression.
|
---|
| 76 | *> \endverbatim
|
---|
| 77 | *
|
---|
| 78 | * Authors:
|
---|
| 79 | * ========
|
---|
| 80 | *
|
---|
| 81 | *> \author Univ. of Tennessee
|
---|
| 82 | *> \author Univ. of California Berkeley
|
---|
| 83 | *> \author Univ. of Colorado Denver
|
---|
| 84 | *> \author NAG Ltd.
|
---|
| 85 | *
|
---|
| 86 | *> \date November 2011
|
---|
| 87 | *
|
---|
| 88 | *> \ingroup auxOTHERauxiliary
|
---|
| 89 | *
|
---|
| 90 | * =====================================================================
|
---|
| 91 | SUBROUTINE SLADIV( A, B, C, D, P, Q )
|
---|
| 92 | *
|
---|
| 93 | * -- LAPACK auxiliary routine (version 3.4.0) --
|
---|
| 94 | * -- LAPACK is a software package provided by Univ. of Tennessee, --
|
---|
| 95 | * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
|
---|
| 96 | * November 2011
|
---|
| 97 | *
|
---|
| 98 | * .. Scalar Arguments ..
|
---|
| 99 | REAL A, B, C, D, P, Q
|
---|
| 100 | * ..
|
---|
| 101 | *
|
---|
| 102 | * =====================================================================
|
---|
| 103 | *
|
---|
| 104 | * .. Local Scalars ..
|
---|
| 105 | REAL E, F
|
---|
| 106 | * ..
|
---|
| 107 | * .. Intrinsic Functions ..
|
---|
| 108 | INTRINSIC ABS
|
---|
| 109 | * ..
|
---|
| 110 | * .. Executable Statements ..
|
---|
| 111 | *
|
---|
| 112 | IF( ABS( D ).LT.ABS( C ) ) THEN
|
---|
| 113 | E = D / C
|
---|
| 114 | F = C + D*E
|
---|
| 115 | P = ( A+B*E ) / F
|
---|
| 116 | Q = ( B-A*E ) / F
|
---|
| 117 | ELSE
|
---|
| 118 | E = C / D
|
---|
| 119 | F = D + C*E
|
---|
| 120 | P = ( B+A*E ) / F
|
---|
| 121 | Q = ( -A+B*E ) / F
|
---|
| 122 | END IF
|
---|
| 123 | *
|
---|
| 124 | RETURN
|
---|
| 125 | *
|
---|
| 126 | * End of SLADIV
|
---|
| 127 | *
|
---|
| 128 | END
|
---|