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ilaenv2stage.f
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*> \brief \b ILAENV2STAGE
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download ILAENV2STAGE + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ilaenv2stage.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ilaenv2stage.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ilaenv2stage.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* INTEGER FUNCTION ILAENV2STAGE( ISPEC, NAME, OPTS, N1, N2, N3, N4 )
*
* .. Scalar Arguments ..
* CHARACTER*( * ) NAME, OPTS
* INTEGER ISPEC, N1, N2, N3, N4
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> ILAENV2STAGE is called from the LAPACK routines to choose problem-dependent
*> parameters for the local environment. See ISPEC for a description of
*> the parameters.
*> It sets problem and machine dependent parameters useful for *_2STAGE and
*> related subroutines.
*>
*> ILAENV2STAGE returns an INTEGER
*> if ILAENV2STAGE >= 0: ILAENV2STAGE returns the value of the parameter
*> specified by ISPEC
*> if ILAENV2STAGE < 0: if ILAENV2STAGE = -k, the k-th argument had an
*> illegal value.
*>
*> This version provides a set of parameters which should give good,
*> but not optimal, performance on many of the currently available
*> computers for the 2-stage solvers. Users are encouraged to modify this
*> subroutine to set the tuning parameters for their particular machine using
*> the option and problem size information in the arguments.
*>
*> This routine will not function correctly if it is converted to all
*> lower case. Converting it to all upper case is allowed.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] ISPEC
*> \verbatim
*> ISPEC is INTEGER
*> Specifies the parameter to be returned as the value of
*> ILAENV2STAGE.
*> = 1: the optimal blocksize nb for the reduction to BAND
*>
*> = 2: the optimal blocksize ib for the eigenvectors
*> singular vectors update routine
*>
*> = 3: The length of the array that store the Housholder
*> representation for the second stage
*> Band to Tridiagonal or Bidiagonal
*>
*> = 4: The workspace needed for the routine in input.
*>
*> = 5: For future release.
*> \endverbatim
*>
*> \param[in] NAME
*> \verbatim
*> NAME is CHARACTER*(*)
*> The name of the calling subroutine, in either upper case or
*> lower case.
*> \endverbatim
*>
*> \param[in] OPTS
*> \verbatim
*> OPTS is CHARACTER*(*)
*> The character options to the subroutine NAME, concatenated
*> into a single character string. For example, UPLO = 'U',
*> TRANS = 'T', and DIAG = 'N' for a triangular routine would
*> be specified as OPTS = 'UTN'.
*> \endverbatim
*>
*> \param[in] N1
*> \verbatim
*> N1 is INTEGER
*> \endverbatim
*>
*> \param[in] N2
*> \verbatim
*> N2 is INTEGER
*> \endverbatim
*>
*> \param[in] N3
*> \verbatim
*> N3 is INTEGER
*> \endverbatim
*>
*> \param[in] N4
*> \verbatim
*> N4 is INTEGER
*> Problem dimensions for the subroutine NAME; these may not all
*> be required.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*> \author Nick R. Papior
*
*> \date July 2017
*
*> \ingroup OTHERauxiliary
*
*> \par Further Details:
* =====================
*>
*> \verbatim
*>
*> The following conventions have been used when calling ILAENV2STAGE
*> from the LAPACK routines:
*> 1) OPTS is a concatenation of all of the character options to
*> subroutine NAME, in the same order that they appear in the
*> argument list for NAME, even if they are not used in determining
*> the value of the parameter specified by ISPEC.
*> 2) The problem dimensions N1, N2, N3, N4 are specified in the order
*> that they appear in the argument list for NAME. N1 is used
*> first, N2 second, and so on, and unused problem dimensions are
*> passed a value of -1.
*> 3) The parameter value returned by ILAENV2STAGE is checked for validity in
*> the calling subroutine.
*>
*> \endverbatim
*>
* =====================================================================
INTEGER FUNCTION ILAENV2STAGE( ISPEC, NAME, OPTS, N1, N2, N3, N4 )
*
* -- LAPACK auxiliary routine (version 3.8.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* July 2017
*
* .. Scalar Arguments ..
CHARACTER*( * ) NAME, OPTS
INTEGER ISPEC, N1, N2, N3, N4
* ..
*
* =====================================================================
* ..
* .. Local Scalars ..
INTEGER IISPEC
* ..
* .. External Functions ..
INTEGER IPARAM2STAGE
EXTERNAL IPARAM2STAGE
* ..
* .. Executable Statements ..
*
GO TO ( 10, 10, 10, 10, 10 )ISPEC
*
* Invalid value for ISPEC
*
ILAENV2STAGE = -1
RETURN
*
10 CONTINUE
*
* 2stage eigenvalues and SVD or related subroutines.
*
IISPEC = 16 + ISPEC
ILAENV2STAGE = IPARAM2STAGE( IISPEC, NAME, OPTS,
$ N1, N2, N3, N4 )
RETURN
*
* End of ILAENV2STAGE
*
END