| *> \brief \b DLADIV | |
| * | |
| * =========== DOCUMENTATION =========== | |
| * | |
| * Online html documentation available at | |
| * http://www.netlib.org/lapack/explore-html/ | |
| * | |
| *> \htmlonly | |
| *> Download DLADIV + dependencies | |
| *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dladiv.f"> | |
| *> [TGZ]</a> | |
| *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dladiv.f"> | |
| *> [ZIP]</a> | |
| *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dladiv.f"> | |
| *> [TXT]</a> | |
| *> \endhtmlonly | |
| * | |
| * Definition: | |
| * =========== | |
| * | |
| * SUBROUTINE DLADIV( A, B, C, D, P, Q ) | |
| * | |
| * .. Scalar Arguments .. | |
| * DOUBLE PRECISION A, B, C, D, P, Q | |
| * .. | |
| * | |
| * | |
| *> \par Purpose: | |
| * ============= | |
| *> | |
| *> \verbatim | |
| *> | |
| *> DLADIV performs complex division in real arithmetic | |
| *> | |
| *> a + i*b | |
| *> p + i*q = --------- | |
| *> c + i*d | |
| *> | |
| *> The algorithm is due to Robert L. Smith and can be found | |
| *> in D. Knuth, The art of Computer Programming, Vol.2, p.195 | |
| *> \endverbatim | |
| * | |
| * Arguments: | |
| * ========== | |
| * | |
| *> \param[in] A | |
| *> \verbatim | |
| *> A is DOUBLE PRECISION | |
| *> \endverbatim | |
| *> | |
| *> \param[in] B | |
| *> \verbatim | |
| *> B is DOUBLE PRECISION | |
| *> \endverbatim | |
| *> | |
| *> \param[in] C | |
| *> \verbatim | |
| *> C is DOUBLE PRECISION | |
| *> \endverbatim | |
| *> | |
| *> \param[in] D | |
| *> \verbatim | |
| *> D is DOUBLE PRECISION | |
| *> The scalars a, b, c, and d in the above expression. | |
| *> \endverbatim | |
| *> | |
| *> \param[out] P | |
| *> \verbatim | |
| *> P is DOUBLE PRECISION | |
| *> \endverbatim | |
| *> | |
| *> \param[out] Q | |
| *> \verbatim | |
| *> Q is DOUBLE PRECISION | |
| *> The scalars p and q in the above expression. | |
| *> \endverbatim | |
| * | |
| * Authors: | |
| * ======== | |
| * | |
| *> \author Univ. of Tennessee | |
| *> \author Univ. of California Berkeley | |
| *> \author Univ. of Colorado Denver | |
| *> \author NAG Ltd. | |
| * | |
| *> \date November 2011 | |
| * | |
| *> \ingroup auxOTHERauxiliary | |
| * | |
| * ===================================================================== | |
| SUBROUTINE DLADIV( A, B, C, D, P, Q ) | |
| * | |
| * -- LAPACK auxiliary routine (version 3.4.0) -- | |
| * -- LAPACK is a software package provided by Univ. of Tennessee, -- | |
| * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- | |
| * November 2011 | |
| * | |
| * .. Scalar Arguments .. | |
| DOUBLE PRECISION A, B, C, D, P, Q | |
| * .. | |
| * | |
| * ===================================================================== | |
| * | |
| * .. Local Scalars .. | |
| DOUBLE PRECISION E, F | |
| * .. | |
| * .. Intrinsic Functions .. | |
| INTRINSIC ABS | |
| * .. | |
| * .. Executable Statements .. | |
| * | |
| IF( ABS( D ).LT.ABS( C ) ) THEN | |
| E = D / C | |
| F = C + D*E | |
| P = ( A+B*E ) / F | |
| Q = ( B-A*E ) / F | |
| ELSE | |
| E = C / D | |
| F = D + C*E | |
| P = ( B+A*E ) / F | |
| Q = ( -A+B*E ) / F | |
| END IF | |
| * | |
| RETURN | |
| * | |
| * End of DLADIV | |
| * | |
| END | |