added lapack 3.7.0 with latest patches from git
This commit is contained in:
544
lapack-netlib/SRC/stgexc.f
Normal file
544
lapack-netlib/SRC/stgexc.f
Normal file
@@ -0,0 +1,544 @@
|
||||
*> \brief \b STGEXC
|
||||
*
|
||||
* =========== DOCUMENTATION ===========
|
||||
*
|
||||
* Online html documentation available at
|
||||
* http://www.netlib.org/lapack/explore-html/
|
||||
*
|
||||
*> \htmlonly
|
||||
*> Download STGEXC + dependencies
|
||||
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/stgexc.f">
|
||||
*> [TGZ]</a>
|
||||
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/stgexc.f">
|
||||
*> [ZIP]</a>
|
||||
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/stgexc.f">
|
||||
*> [TXT]</a>
|
||||
*> \endhtmlonly
|
||||
*
|
||||
* Definition:
|
||||
* ===========
|
||||
*
|
||||
* SUBROUTINE STGEXC( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z,
|
||||
* LDZ, IFST, ILST, WORK, LWORK, INFO )
|
||||
*
|
||||
* .. Scalar Arguments ..
|
||||
* LOGICAL WANTQ, WANTZ
|
||||
* INTEGER IFST, ILST, INFO, LDA, LDB, LDQ, LDZ, LWORK, N
|
||||
* ..
|
||||
* .. Array Arguments ..
|
||||
* REAL A( LDA, * ), B( LDB, * ), Q( LDQ, * ),
|
||||
* $ WORK( * ), Z( LDZ, * )
|
||||
* ..
|
||||
*
|
||||
*
|
||||
*> \par Purpose:
|
||||
* =============
|
||||
*>
|
||||
*> \verbatim
|
||||
*>
|
||||
*> STGEXC reorders the generalized real Schur decomposition of a real
|
||||
*> matrix pair (A,B) using an orthogonal equivalence transformation
|
||||
*>
|
||||
*> (A, B) = Q * (A, B) * Z**T,
|
||||
*>
|
||||
*> so that the diagonal block of (A, B) with row index IFST is moved
|
||||
*> to row ILST.
|
||||
*>
|
||||
*> (A, B) must be in generalized real Schur canonical form (as returned
|
||||
*> by SGGES), i.e. A is block upper triangular with 1-by-1 and 2-by-2
|
||||
*> diagonal blocks. B is upper triangular.
|
||||
*>
|
||||
*> Optionally, the matrices Q and Z of generalized Schur vectors are
|
||||
*> updated.
|
||||
*>
|
||||
*> Q(in) * A(in) * Z(in)**T = Q(out) * A(out) * Z(out)**T
|
||||
*> Q(in) * B(in) * Z(in)**T = Q(out) * B(out) * Z(out)**T
|
||||
*>
|
||||
*> \endverbatim
|
||||
*
|
||||
* Arguments:
|
||||
* ==========
|
||||
*
|
||||
*> \param[in] WANTQ
|
||||
*> \verbatim
|
||||
*> WANTQ is LOGICAL
|
||||
*> .TRUE. : update the left transformation matrix Q;
|
||||
*> .FALSE.: do not update Q.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in] WANTZ
|
||||
*> \verbatim
|
||||
*> WANTZ is LOGICAL
|
||||
*> .TRUE. : update the right transformation matrix Z;
|
||||
*> .FALSE.: do not update Z.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in] N
|
||||
*> \verbatim
|
||||
*> N is INTEGER
|
||||
*> The order of the matrices A and B. N >= 0.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in,out] A
|
||||
*> \verbatim
|
||||
*> A is REAL array, dimension (LDA,N)
|
||||
*> On entry, the matrix A in generalized real Schur canonical
|
||||
*> form.
|
||||
*> On exit, the updated matrix A, again in generalized
|
||||
*> real Schur canonical form.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in] LDA
|
||||
*> \verbatim
|
||||
*> LDA is INTEGER
|
||||
*> The leading dimension of the array A. LDA >= max(1,N).
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in,out] B
|
||||
*> \verbatim
|
||||
*> B is REAL array, dimension (LDB,N)
|
||||
*> On entry, the matrix B in generalized real Schur canonical
|
||||
*> form (A,B).
|
||||
*> On exit, the updated matrix B, again in generalized
|
||||
*> real Schur canonical form (A,B).
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in] LDB
|
||||
*> \verbatim
|
||||
*> LDB is INTEGER
|
||||
*> The leading dimension of the array B. LDB >= max(1,N).
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in,out] Q
|
||||
*> \verbatim
|
||||
*> Q is REAL array, dimension (LDZ,N)
|
||||
*> On entry, if WANTQ = .TRUE., the orthogonal matrix Q.
|
||||
*> On exit, the updated matrix Q.
|
||||
*> If WANTQ = .FALSE., Q is not referenced.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in] LDQ
|
||||
*> \verbatim
|
||||
*> LDQ is INTEGER
|
||||
*> The leading dimension of the array Q. LDQ >= 1.
|
||||
*> If WANTQ = .TRUE., LDQ >= N.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in,out] Z
|
||||
*> \verbatim
|
||||
*> Z is REAL array, dimension (LDZ,N)
|
||||
*> On entry, if WANTZ = .TRUE., the orthogonal matrix Z.
|
||||
*> On exit, the updated matrix Z.
|
||||
*> If WANTZ = .FALSE., Z is not referenced.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in] LDZ
|
||||
*> \verbatim
|
||||
*> LDZ is INTEGER
|
||||
*> The leading dimension of the array Z. LDZ >= 1.
|
||||
*> If WANTZ = .TRUE., LDZ >= N.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in,out] IFST
|
||||
*> \verbatim
|
||||
*> IFST is INTEGER
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in,out] ILST
|
||||
*> \verbatim
|
||||
*> ILST is INTEGER
|
||||
*> Specify the reordering of the diagonal blocks of (A, B).
|
||||
*> The block with row index IFST is moved to row ILST, by a
|
||||
*> sequence of swapping between adjacent blocks.
|
||||
*> On exit, if IFST pointed on entry to the second row of
|
||||
*> a 2-by-2 block, it is changed to point to the first row;
|
||||
*> ILST always points to the first row of the block in its
|
||||
*> final position (which may differ from its input value by
|
||||
*> +1 or -1). 1 <= IFST, ILST <= N.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[out] WORK
|
||||
*> \verbatim
|
||||
*> WORK is REAL array, dimension (MAX(1,LWORK))
|
||||
*> On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[in] LWORK
|
||||
*> \verbatim
|
||||
*> LWORK is INTEGER
|
||||
*> The dimension of the array WORK.
|
||||
*> LWORK >= 1 when N <= 1, otherwise LWORK >= 4*N + 16.
|
||||
*>
|
||||
*> If LWORK = -1, then a workspace query is assumed; the routine
|
||||
*> only calculates the optimal size of the WORK array, returns
|
||||
*> this value as the first entry of the WORK array, and no error
|
||||
*> message related to LWORK is issued by XERBLA.
|
||||
*> \endverbatim
|
||||
*>
|
||||
*> \param[out] INFO
|
||||
*> \verbatim
|
||||
*> INFO is INTEGER
|
||||
*> =0: successful exit.
|
||||
*> <0: if INFO = -i, the i-th argument had an illegal value.
|
||||
*> =1: The transformed matrix pair (A, B) would be too far
|
||||
*> from generalized Schur form; the problem is ill-
|
||||
*> conditioned. (A, B) may have been partially reordered,
|
||||
*> and ILST points to the first row of the current
|
||||
*> position of the block being moved.
|
||||
*> \endverbatim
|
||||
*
|
||||
* Authors:
|
||||
* ========
|
||||
*
|
||||
*> \author Univ. of Tennessee
|
||||
*> \author Univ. of California Berkeley
|
||||
*> \author Univ. of Colorado Denver
|
||||
*> \author NAG Ltd.
|
||||
*
|
||||
*> \date December 2016
|
||||
*
|
||||
*> \ingroup realGEcomputational
|
||||
*
|
||||
*> \par Contributors:
|
||||
* ==================
|
||||
*>
|
||||
*> Bo Kagstrom and Peter Poromaa, Department of Computing Science,
|
||||
*> Umea University, S-901 87 Umea, Sweden.
|
||||
*
|
||||
*> \par References:
|
||||
* ================
|
||||
*>
|
||||
*> \verbatim
|
||||
*>
|
||||
*> [1] B. Kagstrom; A Direct Method for Reordering Eigenvalues in the
|
||||
*> Generalized Real Schur Form of a Regular Matrix Pair (A, B), in
|
||||
*> M.S. Moonen et al (eds), Linear Algebra for Large Scale and
|
||||
*> Real-Time Applications, Kluwer Academic Publ. 1993, pp 195-218.
|
||||
*> \endverbatim
|
||||
*>
|
||||
* =====================================================================
|
||||
SUBROUTINE STGEXC( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z,
|
||||
$ LDZ, IFST, ILST, WORK, LWORK, INFO )
|
||||
*
|
||||
* -- LAPACK computational routine (version 3.7.0) --
|
||||
* -- LAPACK is a software package provided by Univ. of Tennessee, --
|
||||
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
|
||||
* December 2016
|
||||
*
|
||||
* .. Scalar Arguments ..
|
||||
LOGICAL WANTQ, WANTZ
|
||||
INTEGER IFST, ILST, INFO, LDA, LDB, LDQ, LDZ, LWORK, N
|
||||
* ..
|
||||
* .. Array Arguments ..
|
||||
REAL A( LDA, * ), B( LDB, * ), Q( LDQ, * ),
|
||||
$ WORK( * ), Z( LDZ, * )
|
||||
* ..
|
||||
*
|
||||
* =====================================================================
|
||||
*
|
||||
* .. Parameters ..
|
||||
REAL ZERO
|
||||
PARAMETER ( ZERO = 0.0E+0 )
|
||||
* ..
|
||||
* .. Local Scalars ..
|
||||
LOGICAL LQUERY
|
||||
INTEGER HERE, LWMIN, NBF, NBL, NBNEXT
|
||||
* ..
|
||||
* .. External Subroutines ..
|
||||
EXTERNAL STGEX2, XERBLA
|
||||
* ..
|
||||
* .. Intrinsic Functions ..
|
||||
INTRINSIC MAX
|
||||
* ..
|
||||
* .. Executable Statements ..
|
||||
*
|
||||
* Decode and test input arguments.
|
||||
*
|
||||
INFO = 0
|
||||
LQUERY = ( LWORK.EQ.-1 )
|
||||
IF( N.LT.0 ) THEN
|
||||
INFO = -3
|
||||
ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
|
||||
INFO = -5
|
||||
ELSE IF( LDB.LT.MAX( 1, N ) ) THEN
|
||||
INFO = -7
|
||||
ELSE IF( LDQ.LT.1 .OR. WANTQ .AND. ( LDQ.LT.MAX( 1, N ) ) ) THEN
|
||||
INFO = -9
|
||||
ELSE IF( LDZ.LT.1 .OR. WANTZ .AND. ( LDZ.LT.MAX( 1, N ) ) ) THEN
|
||||
INFO = -11
|
||||
ELSE IF( IFST.LT.1 .OR. IFST.GT.N ) THEN
|
||||
INFO = -12
|
||||
ELSE IF( ILST.LT.1 .OR. ILST.GT.N ) THEN
|
||||
INFO = -13
|
||||
END IF
|
||||
*
|
||||
IF( INFO.EQ.0 ) THEN
|
||||
IF( N.LE.1 ) THEN
|
||||
LWMIN = 1
|
||||
ELSE
|
||||
LWMIN = 4*N + 16
|
||||
END IF
|
||||
WORK(1) = LWMIN
|
||||
*
|
||||
IF (LWORK.LT.LWMIN .AND. .NOT.LQUERY) THEN
|
||||
INFO = -15
|
||||
END IF
|
||||
END IF
|
||||
*
|
||||
IF( INFO.NE.0 ) THEN
|
||||
CALL XERBLA( 'STGEXC', -INFO )
|
||||
RETURN
|
||||
ELSE IF( LQUERY ) THEN
|
||||
RETURN
|
||||
END IF
|
||||
*
|
||||
* Quick return if possible
|
||||
*
|
||||
IF( N.LE.1 )
|
||||
$ RETURN
|
||||
*
|
||||
* Determine the first row of the specified block and find out
|
||||
* if it is 1-by-1 or 2-by-2.
|
||||
*
|
||||
IF( IFST.GT.1 ) THEN
|
||||
IF( A( IFST, IFST-1 ).NE.ZERO )
|
||||
$ IFST = IFST - 1
|
||||
END IF
|
||||
NBF = 1
|
||||
IF( IFST.LT.N ) THEN
|
||||
IF( A( IFST+1, IFST ).NE.ZERO )
|
||||
$ NBF = 2
|
||||
END IF
|
||||
*
|
||||
* Determine the first row of the final block
|
||||
* and find out if it is 1-by-1 or 2-by-2.
|
||||
*
|
||||
IF( ILST.GT.1 ) THEN
|
||||
IF( A( ILST, ILST-1 ).NE.ZERO )
|
||||
$ ILST = ILST - 1
|
||||
END IF
|
||||
NBL = 1
|
||||
IF( ILST.LT.N ) THEN
|
||||
IF( A( ILST+1, ILST ).NE.ZERO )
|
||||
$ NBL = 2
|
||||
END IF
|
||||
IF( IFST.EQ.ILST )
|
||||
$ RETURN
|
||||
*
|
||||
IF( IFST.LT.ILST ) THEN
|
||||
*
|
||||
* Update ILST.
|
||||
*
|
||||
IF( NBF.EQ.2 .AND. NBL.EQ.1 )
|
||||
$ ILST = ILST - 1
|
||||
IF( NBF.EQ.1 .AND. NBL.EQ.2 )
|
||||
$ ILST = ILST + 1
|
||||
*
|
||||
HERE = IFST
|
||||
*
|
||||
10 CONTINUE
|
||||
*
|
||||
* Swap with next one below.
|
||||
*
|
||||
IF( NBF.EQ.1 .OR. NBF.EQ.2 ) THEN
|
||||
*
|
||||
* Current block either 1-by-1 or 2-by-2.
|
||||
*
|
||||
NBNEXT = 1
|
||||
IF( HERE+NBF+1.LE.N ) THEN
|
||||
IF( A( HERE+NBF+1, HERE+NBF ).NE.ZERO )
|
||||
$ NBNEXT = 2
|
||||
END IF
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z,
|
||||
$ LDZ, HERE, NBF, NBNEXT, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE + NBNEXT
|
||||
*
|
||||
* Test if 2-by-2 block breaks into two 1-by-1 blocks.
|
||||
*
|
||||
IF( NBF.EQ.2 ) THEN
|
||||
IF( A( HERE+1, HERE ).EQ.ZERO )
|
||||
$ NBF = 3
|
||||
END IF
|
||||
*
|
||||
ELSE
|
||||
*
|
||||
* Current block consists of two 1-by-1 blocks, each of which
|
||||
* must be swapped individually.
|
||||
*
|
||||
NBNEXT = 1
|
||||
IF( HERE+3.LE.N ) THEN
|
||||
IF( A( HERE+3, HERE+2 ).NE.ZERO )
|
||||
$ NBNEXT = 2
|
||||
END IF
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z,
|
||||
$ LDZ, HERE+1, 1, NBNEXT, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
IF( NBNEXT.EQ.1 ) THEN
|
||||
*
|
||||
* Swap two 1-by-1 blocks.
|
||||
*
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z,
|
||||
$ LDZ, HERE, 1, 1, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE + 1
|
||||
*
|
||||
ELSE
|
||||
*
|
||||
* Recompute NBNEXT in case of 2-by-2 split.
|
||||
*
|
||||
IF( A( HERE+2, HERE+1 ).EQ.ZERO )
|
||||
$ NBNEXT = 1
|
||||
IF( NBNEXT.EQ.2 ) THEN
|
||||
*
|
||||
* 2-by-2 block did not split.
|
||||
*
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ,
|
||||
$ Z, LDZ, HERE, 1, NBNEXT, WORK, LWORK,
|
||||
$ INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE + 2
|
||||
ELSE
|
||||
*
|
||||
* 2-by-2 block did split.
|
||||
*
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ,
|
||||
$ Z, LDZ, HERE, 1, 1, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE + 1
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ,
|
||||
$ Z, LDZ, HERE, 1, 1, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE + 1
|
||||
END IF
|
||||
*
|
||||
END IF
|
||||
END IF
|
||||
IF( HERE.LT.ILST )
|
||||
$ GO TO 10
|
||||
ELSE
|
||||
HERE = IFST
|
||||
*
|
||||
20 CONTINUE
|
||||
*
|
||||
* Swap with next one below.
|
||||
*
|
||||
IF( NBF.EQ.1 .OR. NBF.EQ.2 ) THEN
|
||||
*
|
||||
* Current block either 1-by-1 or 2-by-2.
|
||||
*
|
||||
NBNEXT = 1
|
||||
IF( HERE.GE.3 ) THEN
|
||||
IF( A( HERE-1, HERE-2 ).NE.ZERO )
|
||||
$ NBNEXT = 2
|
||||
END IF
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z,
|
||||
$ LDZ, HERE-NBNEXT, NBNEXT, NBF, WORK, LWORK,
|
||||
$ INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE - NBNEXT
|
||||
*
|
||||
* Test if 2-by-2 block breaks into two 1-by-1 blocks.
|
||||
*
|
||||
IF( NBF.EQ.2 ) THEN
|
||||
IF( A( HERE+1, HERE ).EQ.ZERO )
|
||||
$ NBF = 3
|
||||
END IF
|
||||
*
|
||||
ELSE
|
||||
*
|
||||
* Current block consists of two 1-by-1 blocks, each of which
|
||||
* must be swapped individually.
|
||||
*
|
||||
NBNEXT = 1
|
||||
IF( HERE.GE.3 ) THEN
|
||||
IF( A( HERE-1, HERE-2 ).NE.ZERO )
|
||||
$ NBNEXT = 2
|
||||
END IF
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z,
|
||||
$ LDZ, HERE-NBNEXT, NBNEXT, 1, WORK, LWORK,
|
||||
$ INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
IF( NBNEXT.EQ.1 ) THEN
|
||||
*
|
||||
* Swap two 1-by-1 blocks.
|
||||
*
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z,
|
||||
$ LDZ, HERE, NBNEXT, 1, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE - 1
|
||||
ELSE
|
||||
*
|
||||
* Recompute NBNEXT in case of 2-by-2 split.
|
||||
*
|
||||
IF( A( HERE, HERE-1 ).EQ.ZERO )
|
||||
$ NBNEXT = 1
|
||||
IF( NBNEXT.EQ.2 ) THEN
|
||||
*
|
||||
* 2-by-2 block did not split.
|
||||
*
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ,
|
||||
$ Z, LDZ, HERE-1, 2, 1, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE - 2
|
||||
ELSE
|
||||
*
|
||||
* 2-by-2 block did split.
|
||||
*
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ,
|
||||
$ Z, LDZ, HERE, 1, 1, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE - 1
|
||||
CALL STGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ,
|
||||
$ Z, LDZ, HERE, 1, 1, WORK, LWORK, INFO )
|
||||
IF( INFO.NE.0 ) THEN
|
||||
ILST = HERE
|
||||
RETURN
|
||||
END IF
|
||||
HERE = HERE - 1
|
||||
END IF
|
||||
END IF
|
||||
END IF
|
||||
IF( HERE.GT.ILST )
|
||||
$ GO TO 20
|
||||
END IF
|
||||
ILST = HERE
|
||||
WORK( 1 ) = LWMIN
|
||||
RETURN
|
||||
*
|
||||
* End of STGEXC
|
||||
*
|
||||
END
|
||||
Reference in New Issue
Block a user