Add graph references
This commit is contained in:
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@@ -0,0 +1,574 @@
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/* -- translated by f2c (version 20240504).
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You must link the resulting object file with libf2c:
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on Microsoft Windows system, link with libf2c.lib;
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on Linux or Unix systems, link with .../path/to/libf2c.a -lm
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||||
or, if you install libf2c.a in a standard place, with -lf2c -lm
|
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-- in that order, at the end of the command line, as in
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cc *.o -lf2c -lm
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
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http://www.netlib.org/f2c/libf2c.zip
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*/
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#include "f2c.h"
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/* Table of constant values */
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static doublereal c_b11 = 0.;
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static doublereal c_b12 = 1.;
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static integer c__12 = 12;
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static integer c__2 = 2;
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static integer c__49 = 49;
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/* > \brief \b DHSEQR
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=========== DOCUMENTATION ===========
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Online html documentation available at
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http://www.netlib.org/lapack/explore-html/
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> \htmlonly
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> Download DHSEQR + dependencies
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> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dhseqr.
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f">
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> [TGZ]</a>
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> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dhseqr.
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f">
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> [ZIP]</a>
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> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dhseqr.
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f">
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> [TXT]</a>
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> \endhtmlonly
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Definition:
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===========
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SUBROUTINE DHSEQR( JOB, COMPZ, N, ILO, IHI, H, LDH, WR, WI, Z,
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LDZ, WORK, LWORK, INFO )
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INTEGER IHI, ILO, INFO, LDH, LDZ, LWORK, N
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CHARACTER COMPZ, JOB
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DOUBLE PRECISION H( LDH, * ), WI( * ), WORK( * ), WR( * ),
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$ Z( LDZ, * )
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> \par Purpose:
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=============
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>
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> \verbatim
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>
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> DHSEQR computes the eigenvalues of a Hessenberg matrix H
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> and, optionally, the matrices T and Z from the Schur decomposition
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> H = Z T Z**T, where T is an upper quasi-triangular matrix (the
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> Schur form), and Z is the orthogonal matrix of Schur vectors.
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>
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> Optionally Z may be postmultiplied into an input orthogonal
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> matrix Q so that this routine can give the Schur factorization
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> of a matrix A which has been reduced to the Hessenberg form H
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> by the orthogonal matrix Q: A = Q*H*Q**T = (QZ)*T*(QZ)**T.
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> \endverbatim
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Arguments:
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==========
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> \param[in] JOB
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> \verbatim
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> JOB is CHARACTER*1
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> = 'E': compute eigenvalues only;
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> = 'S': compute eigenvalues and the Schur form T.
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> \endverbatim
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>
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> \param[in] COMPZ
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> \verbatim
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> COMPZ is CHARACTER*1
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> = 'N': no Schur vectors are computed;
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> = 'I': Z is initialized to the unit matrix and the matrix Z
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> of Schur vectors of H is returned;
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> = 'V': Z must contain an orthogonal matrix Q on entry, and
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> the product Q*Z is returned.
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> \endverbatim
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>
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> \param[in] N
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> \verbatim
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> N is INTEGER
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> The order of the matrix H. N .GE. 0.
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> \endverbatim
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>
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> \param[in] ILO
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> \verbatim
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> ILO is INTEGER
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> \endverbatim
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>
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> \param[in] IHI
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> \verbatim
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> IHI is INTEGER
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>
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> It is assumed that H is already upper triangular in rows
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> and columns 1:ILO-1 and IHI+1:N. ILO and IHI are normally
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> set by a previous call to DGEBAL, and then passed to ZGEHRD
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> when the matrix output by DGEBAL is reduced to Hessenberg
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> form. Otherwise ILO and IHI should be set to 1 and N
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> respectively. If N.GT.0, then 1.LE.ILO.LE.IHI.LE.N.
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> If N = 0, then ILO = 1 and IHI = 0.
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> \endverbatim
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||||
>
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> \param[in,out] H
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> \verbatim
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> H is DOUBLE PRECISION array, dimension (LDH,N)
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> On entry, the upper Hessenberg matrix H.
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> On exit, if INFO = 0 and JOB = 'S', then H contains the
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> upper quasi-triangular matrix T from the Schur decomposition
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> (the Schur form); 2-by-2 diagonal blocks (corresponding to
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> complex conjugate pairs of eigenvalues) are returned in
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> standard form, with H(i,i) = H(i+1,i+1) and
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> H(i+1,i)*H(i,i+1).LT.0. If INFO = 0 and JOB = 'E', the
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> contents of H are unspecified on exit. (The output value of
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> H when INFO.GT.0 is given under the description of INFO
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> below.)
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>
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> Unlike earlier versions of DHSEQR, this subroutine may
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> explicitly H(i,j) = 0 for i.GT.j and j = 1, 2, ... ILO-1
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> or j = IHI+1, IHI+2, ... N.
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> \endverbatim
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>
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> \param[in] LDH
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> \verbatim
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> LDH is INTEGER
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> The leading dimension of the array H. LDH .GE. max(1,N).
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> \endverbatim
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>
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> \param[out] WR
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> \verbatim
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> WR is DOUBLE PRECISION array, dimension (N)
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> \endverbatim
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||||
>
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> \param[out] WI
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> \verbatim
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> WI is DOUBLE PRECISION array, dimension (N)
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>
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> The real and imaginary parts, respectively, of the computed
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> eigenvalues. If two eigenvalues are computed as a complex
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> conjugate pair, they are stored in consecutive elements of
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> WR and WI, say the i-th and (i+1)th, with WI(i) .GT. 0 and
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> WI(i+1) .LT. 0. If JOB = 'S', the eigenvalues are stored in
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> the same order as on the diagonal of the Schur form returned
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> in H, with WR(i) = H(i,i) and, if H(i:i+1,i:i+1) is a 2-by-2
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> diagonal block, WI(i) = sqrt(-H(i+1,i)*H(i,i+1)) and
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> WI(i+1) = -WI(i).
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||||
> \endverbatim
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||||
>
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||||
> \param[in,out] Z
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||||
> \verbatim
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||||
> Z is DOUBLE PRECISION array, dimension (LDZ,N)
|
||||
> If COMPZ = 'N', Z is not referenced.
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||||
> If COMPZ = 'I', on entry Z need not be set and on exit,
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||||
> if INFO = 0, Z contains the orthogonal matrix Z of the Schur
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||||
> vectors of H. If COMPZ = 'V', on entry Z must contain an
|
||||
> N-by-N matrix Q, which is assumed to be equal to the unit
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||||
> matrix except for the submatrix Z(ILO:IHI,ILO:IHI). On exit,
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||||
> if INFO = 0, Z contains Q*Z.
|
||||
> Normally Q is the orthogonal matrix generated by DORGHR
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||||
> after the call to DGEHRD which formed the Hessenberg matrix
|
||||
> H. (The output value of Z when INFO.GT.0 is given under
|
||||
> the description of INFO below.)
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||||
> \endverbatim
|
||||
>
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||||
> \param[in] LDZ
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||||
> \verbatim
|
||||
> LDZ is INTEGER
|
||||
> The leading dimension of the array Z. if COMPZ = 'I' or
|
||||
> COMPZ = 'V', then LDZ.GE.MAX(1,N). Otherwize, LDZ.GE.1.
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> \endverbatim
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||||
>
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||||
> \param[out] WORK
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||||
> \verbatim
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||||
> WORK is DOUBLE PRECISION array, dimension (LWORK)
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||||
> On exit, if INFO = 0, WORK(1) returns an estimate of
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||||
> the optimal value for LWORK.
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||||
> \endverbatim
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||||
>
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||||
> \param[in] LWORK
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||||
> \verbatim
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||||
> LWORK is INTEGER
|
||||
> The dimension of the array WORK. LWORK .GE. max(1,N)
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||||
> is sufficient and delivers very good and sometimes
|
||||
> optimal performance. However, LWORK as large as 11*N
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||||
> may be required for optimal performance. A workspace
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> query is recommended to determine the optimal workspace
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> size.
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>
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> If LWORK = -1, then DHSEQR does a workspace query.
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||||
> In this case, DHSEQR checks the input parameters and
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> estimates the optimal workspace size for the given
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> values of N, ILO and IHI. The estimate is returned
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> in WORK(1). No error message related to LWORK is
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||||
> issued by XERBLA. Neither H nor Z are accessed.
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> \endverbatim
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||||
>
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||||
> \param[out] INFO
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||||
> \verbatim
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||||
> INFO is INTEGER
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||||
> = 0: successful exit
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||||
> .LT. 0: if INFO = -i, the i-th argument had an illegal
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||||
> value
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||||
> .GT. 0: if INFO = i, DHSEQR failed to compute all of
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||||
> the eigenvalues. Elements 1:ilo-1 and i+1:n of WR
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||||
> and WI contain those eigenvalues which have been
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||||
> successfully computed. (Failures are rare.)
|
||||
>
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||||
> If INFO .GT. 0 and JOB = 'E', then on exit, the
|
||||
> remaining unconverged eigenvalues are the eigen-
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||||
> values of the upper Hessenberg matrix rows and
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||||
> columns ILO through INFO of the final, output
|
||||
> value of H.
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||||
>
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||||
> If INFO .GT. 0 and JOB = 'S', then on exit
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||||
>
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||||
> (*) (initial value of H)*U = U*(final value of H)
|
||||
>
|
||||
> where U is an orthogonal matrix. The final
|
||||
> value of H is upper Hessenberg and quasi-triangular
|
||||
> in rows and columns INFO+1 through IHI.
|
||||
>
|
||||
> If INFO .GT. 0 and COMPZ = 'V', then on exit
|
||||
>
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||||
> (final value of Z) = (initial value of Z)*U
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||||
>
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||||
> where U is the orthogonal matrix in (*) (regard-
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||||
> less of the value of JOB.)
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||||
>
|
||||
> If INFO .GT. 0 and COMPZ = 'I', then on exit
|
||||
> (final value of Z) = U
|
||||
> where U is the orthogonal matrix in (*) (regard-
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||||
> less of the value of JOB.)
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||||
>
|
||||
> If INFO .GT. 0 and COMPZ = 'N', then Z is not
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||||
> accessed.
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||||
> \endverbatim
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||||
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||||
Authors:
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||||
========
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||||
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||||
> \author Univ. of Tennessee
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> \author Univ. of California Berkeley
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||||
> \author Univ. of Colorado Denver
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||||
> \author NAG Ltd.
|
||||
|
||||
> \date November 2011
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||||
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||||
> \ingroup doubleOTHERcomputational
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||||
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||||
> \par Contributors:
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||||
==================
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||||
>
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||||
> Karen Braman and Ralph Byers, Department of Mathematics,
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||||
> University of Kansas, USA
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||||
|
||||
> \par Further Details:
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||||
=====================
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||||
>
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||||
> \verbatim
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||||
>
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||||
> Default values supplied by
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||||
> ILAENV(ISPEC,'DHSEQR',JOB(:1)//COMPZ(:1),N,ILO,IHI,LWORK).
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||||
> It is suggested that these defaults be adjusted in order
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> to attain best performance in each particular
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> computational environment.
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>
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> ISPEC=12: The DLAHQR vs DLAQR0 crossover point.
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> Default: 75. (Must be at least 11.)
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>
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||||
> ISPEC=13: Recommended deflation window size.
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||||
> This depends on ILO, IHI and NS. NS is the
|
||||
> number of simultaneous shifts returned
|
||||
> by ILAENV(ISPEC=15). (See ISPEC=15 below.)
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||||
> The default for (IHI-ILO+1).LE.500 is NS.
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||||
> The default for (IHI-ILO+1).GT.500 is 3*NS/2.
|
||||
>
|
||||
> ISPEC=14: Nibble crossover point. (See IPARMQ for
|
||||
> details.) Default: 14% of deflation window
|
||||
> size.
|
||||
>
|
||||
> ISPEC=15: Number of simultaneous shifts in a multishift
|
||||
> QR iteration.
|
||||
>
|
||||
> If IHI-ILO+1 is ...
|
||||
>
|
||||
> greater than ...but less ... the
|
||||
> or equal to ... than default is
|
||||
>
|
||||
> 1 30 NS = 2(+)
|
||||
> 30 60 NS = 4(+)
|
||||
> 60 150 NS = 10(+)
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||||
> 150 590 NS = **
|
||||
> 590 3000 NS = 64
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||||
> 3000 6000 NS = 128
|
||||
> 6000 infinity NS = 256
|
||||
>
|
||||
> (+) By default some or all matrices of this order
|
||||
> are passed to the implicit double shift routine
|
||||
> DLAHQR and this parameter is ignored. See
|
||||
> ISPEC=12 above and comments in IPARMQ for
|
||||
> details.
|
||||
>
|
||||
> (**) The asterisks (**) indicate an ad-hoc
|
||||
> function of N increasing from 10 to 64.
|
||||
>
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||||
> ISPEC=16: Select structured matrix multiply.
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||||
> If the number of simultaneous shifts (specified
|
||||
> by ISPEC=15) is less than 14, then the default
|
||||
> for ISPEC=16 is 0. Otherwise the default for
|
||||
> ISPEC=16 is 2.
|
||||
> \endverbatim
|
||||
|
||||
> \par References:
|
||||
================
|
||||
>
|
||||
> K. Braman, R. Byers and R. Mathias, The Multi-Shift QR
|
||||
> Algorithm Part I: Maintaining Well Focused Shifts, and Level 3
|
||||
> Performance, SIAM Journal of Matrix Analysis, volume 23, pages
|
||||
> 929--947, 2002.
|
||||
> \n
|
||||
> K. Braman, R. Byers and R. Mathias, The Multi-Shift QR
|
||||
> Algorithm Part II: Aggressive Early Deflation, SIAM Journal
|
||||
> of Matrix Analysis, volume 23, pages 948--973, 2002.
|
||||
|
||||
=====================================================================
|
||||
Subroutine */ int igraphdhseqr_(char *job, char *compz, integer *n, integer *ilo,
|
||||
integer *ihi, doublereal *h__, integer *ldh, doublereal *wr,
|
||||
doublereal *wi, doublereal *z__, integer *ldz, doublereal *work,
|
||||
integer *lwork, integer *info)
|
||||
{
|
||||
/* System generated locals */
|
||||
address a__1[2];
|
||||
integer h_dim1, h_offset, z_dim1, z_offset, i__1, i__2[2], i__3;
|
||||
doublereal d__1;
|
||||
char ch__1[2];
|
||||
|
||||
/* Builtin functions
|
||||
Subroutine */ int s_cat(char *, char **, integer *, integer *, ftnlen);
|
||||
|
||||
/* Local variables */
|
||||
integer i__;
|
||||
doublereal hl[2401] /* was [49][49] */;
|
||||
integer kbot, nmin;
|
||||
extern logical igraphlsame_(char *, char *);
|
||||
logical initz;
|
||||
doublereal workl[49];
|
||||
logical wantt, wantz;
|
||||
extern /* Subroutine */ int igraphdlaqr0_(logical *, logical *, integer *,
|
||||
integer *, integer *, doublereal *, integer *, doublereal *,
|
||||
doublereal *, integer *, integer *, doublereal *, integer *,
|
||||
doublereal *, integer *, integer *), igraphdlahqr_(logical *, logical *,
|
||||
integer *, integer *, integer *, doublereal *, integer *,
|
||||
doublereal *, doublereal *, integer *, integer *, doublereal *,
|
||||
integer *, integer *), igraphdlacpy_(char *, integer *, integer *,
|
||||
doublereal *, integer *, doublereal *, integer *),
|
||||
igraphdlaset_(char *, integer *, integer *, doublereal *, doublereal *,
|
||||
doublereal *, integer *);
|
||||
extern integer igraphilaenv_(integer *, char *, char *, integer *, integer *,
|
||||
integer *, integer *, ftnlen, ftnlen);
|
||||
extern /* Subroutine */ int igraphxerbla_(char *, integer *, ftnlen);
|
||||
logical lquery;
|
||||
|
||||
|
||||
/* -- LAPACK computational 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
|
||||
|
||||
|
||||
=====================================================================
|
||||
|
||||
|
||||
==== Matrices of order NTINY or smaller must be processed by
|
||||
. DLAHQR because of insufficient subdiagonal scratch space.
|
||||
. (This is a hard limit.) ====
|
||||
|
||||
==== NL allocates some local workspace to help small matrices
|
||||
. through a rare DLAHQR failure. NL .GT. NTINY = 11 is
|
||||
. required and NL .LE. NMIN = ILAENV(ISPEC=12,...) is recom-
|
||||
. mended. (The default value of NMIN is 75.) Using NL = 49
|
||||
. allows up to six simultaneous shifts and a 16-by-16
|
||||
. deflation window. ====
|
||||
|
||||
==== Decode and check the input parameters. ====
|
||||
|
||||
Parameter adjustments */
|
||||
h_dim1 = *ldh;
|
||||
h_offset = 1 + h_dim1;
|
||||
h__ -= h_offset;
|
||||
--wr;
|
||||
--wi;
|
||||
z_dim1 = *ldz;
|
||||
z_offset = 1 + z_dim1;
|
||||
z__ -= z_offset;
|
||||
--work;
|
||||
|
||||
/* Function Body */
|
||||
wantt = igraphlsame_(job, "S");
|
||||
initz = igraphlsame_(compz, "I");
|
||||
wantz = initz || igraphlsame_(compz, "V");
|
||||
work[1] = (doublereal) max(1,*n);
|
||||
lquery = *lwork == -1;
|
||||
|
||||
*info = 0;
|
||||
if (! igraphlsame_(job, "E") && ! wantt) {
|
||||
*info = -1;
|
||||
} else if (! igraphlsame_(compz, "N") && ! wantz) {
|
||||
*info = -2;
|
||||
} else if (*n < 0) {
|
||||
*info = -3;
|
||||
} else if (*ilo < 1 || *ilo > max(1,*n)) {
|
||||
*info = -4;
|
||||
} else if (*ihi < min(*ilo,*n) || *ihi > *n) {
|
||||
*info = -5;
|
||||
} else if (*ldh < max(1,*n)) {
|
||||
*info = -7;
|
||||
} else if (*ldz < 1 || wantz && *ldz < max(1,*n)) {
|
||||
*info = -11;
|
||||
} else if (*lwork < max(1,*n) && ! lquery) {
|
||||
*info = -13;
|
||||
}
|
||||
|
||||
if (*info != 0) {
|
||||
|
||||
/* ==== Quick return in case of invalid argument. ==== */
|
||||
|
||||
i__1 = -(*info);
|
||||
igraphxerbla_("DHSEQR", &i__1, (ftnlen)6);
|
||||
return 0;
|
||||
|
||||
} else if (*n == 0) {
|
||||
|
||||
/* ==== Quick return in case N = 0; nothing to do. ==== */
|
||||
|
||||
return 0;
|
||||
|
||||
} else if (lquery) {
|
||||
|
||||
/* ==== Quick return in case of a workspace query ==== */
|
||||
|
||||
igraphdlaqr0_(&wantt, &wantz, n, ilo, ihi, &h__[h_offset], ldh, &wr[1], &wi[
|
||||
1], ilo, ihi, &z__[z_offset], ldz, &work[1], lwork, info);
|
||||
/* ==== Ensure reported workspace size is backward-compatible with
|
||||
. previous LAPACK versions. ====
|
||||
Computing MAX */
|
||||
d__1 = (doublereal) max(1,*n);
|
||||
work[1] = max(d__1,work[1]);
|
||||
return 0;
|
||||
|
||||
} else {
|
||||
|
||||
/* ==== copy eigenvalues isolated by DGEBAL ==== */
|
||||
|
||||
i__1 = *ilo - 1;
|
||||
for (i__ = 1; i__ <= i__1; ++i__) {
|
||||
wr[i__] = h__[i__ + i__ * h_dim1];
|
||||
wi[i__] = 0.;
|
||||
/* L10: */
|
||||
}
|
||||
i__1 = *n;
|
||||
for (i__ = *ihi + 1; i__ <= i__1; ++i__) {
|
||||
wr[i__] = h__[i__ + i__ * h_dim1];
|
||||
wi[i__] = 0.;
|
||||
/* L20: */
|
||||
}
|
||||
|
||||
/* ==== Initialize Z, if requested ==== */
|
||||
|
||||
if (initz) {
|
||||
igraphdlaset_("A", n, n, &c_b11, &c_b12, &z__[z_offset], ldz)
|
||||
;
|
||||
}
|
||||
|
||||
/* ==== Quick return if possible ==== */
|
||||
|
||||
if (*ilo == *ihi) {
|
||||
wr[*ilo] = h__[*ilo + *ilo * h_dim1];
|
||||
wi[*ilo] = 0.;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* ==== DLAHQR/DLAQR0 crossover point ====
|
||||
|
||||
Writing concatenation */
|
||||
i__2[0] = 1, a__1[0] = job;
|
||||
i__2[1] = 1, a__1[1] = compz;
|
||||
s_cat(ch__1, a__1, i__2, &c__2, (ftnlen)2);
|
||||
nmin = igraphilaenv_(&c__12, "DHSEQR", ch__1, n, ilo, ihi, lwork, (ftnlen)6,
|
||||
(ftnlen)2);
|
||||
nmin = max(11,nmin);
|
||||
|
||||
/* ==== DLAQR0 for big matrices; DLAHQR for small ones ==== */
|
||||
|
||||
if (*n > nmin) {
|
||||
igraphdlaqr0_(&wantt, &wantz, n, ilo, ihi, &h__[h_offset], ldh, &wr[1],
|
||||
&wi[1], ilo, ihi, &z__[z_offset], ldz, &work[1], lwork,
|
||||
info);
|
||||
} else {
|
||||
|
||||
/* ==== Small matrix ==== */
|
||||
|
||||
igraphdlahqr_(&wantt, &wantz, n, ilo, ihi, &h__[h_offset], ldh, &wr[1],
|
||||
&wi[1], ilo, ihi, &z__[z_offset], ldz, info);
|
||||
|
||||
if (*info > 0) {
|
||||
|
||||
/* ==== A rare DLAHQR failure! DLAQR0 sometimes succeeds
|
||||
. when DLAHQR fails. ==== */
|
||||
|
||||
kbot = *info;
|
||||
|
||||
if (*n >= 49) {
|
||||
|
||||
/* ==== Larger matrices have enough subdiagonal scratch
|
||||
. space to call DLAQR0 directly. ==== */
|
||||
|
||||
igraphdlaqr0_(&wantt, &wantz, n, ilo, &kbot, &h__[h_offset],
|
||||
ldh, &wr[1], &wi[1], ilo, ihi, &z__[z_offset],
|
||||
ldz, &work[1], lwork, info);
|
||||
|
||||
} else {
|
||||
|
||||
/* ==== Tiny matrices don't have enough subdiagonal
|
||||
. scratch space to benefit from DLAQR0. Hence,
|
||||
. tiny matrices must be copied into a larger
|
||||
. array before calling DLAQR0. ==== */
|
||||
|
||||
igraphdlacpy_("A", n, n, &h__[h_offset], ldh, hl, &c__49);
|
||||
hl[*n + 1 + *n * 49 - 50] = 0.;
|
||||
i__1 = 49 - *n;
|
||||
igraphdlaset_("A", &c__49, &i__1, &c_b11, &c_b11, &hl[(*n + 1) *
|
||||
49 - 49], &c__49);
|
||||
igraphdlaqr0_(&wantt, &wantz, &c__49, ilo, &kbot, hl, &c__49, &
|
||||
wr[1], &wi[1], ilo, ihi, &z__[z_offset], ldz,
|
||||
workl, &c__49, info);
|
||||
if (wantt || *info != 0) {
|
||||
igraphdlacpy_("A", n, n, hl, &c__49, &h__[h_offset], ldh);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/* ==== Clear out the trash, if necessary. ==== */
|
||||
|
||||
if ((wantt || *info != 0) && *n > 2) {
|
||||
i__1 = *n - 2;
|
||||
i__3 = *n - 2;
|
||||
igraphdlaset_("L", &i__1, &i__3, &c_b11, &c_b11, &h__[h_dim1 + 3], ldh);
|
||||
}
|
||||
|
||||
/* ==== Ensure reported workspace size is backward-compatible with
|
||||
. previous LAPACK versions. ====
|
||||
|
||||
Computing MAX */
|
||||
d__1 = (doublereal) max(1,*n);
|
||||
work[1] = max(d__1,work[1]);
|
||||
}
|
||||
|
||||
/* ==== End of DHSEQR ==== */
|
||||
|
||||
return 0;
|
||||
} /* igraphdhseqr_ */
|
||||
|
||||
Reference in New Issue
Block a user