table of contents
| gsvj0(3) | LAPACK | gsvj0(3) |
NAME¶
gsvj0 - gsvj0: step in gesvj
SYNOPSIS¶
Functions¶
subroutine cgsvj0 (jobv, m, n, a, lda, d, sva, mv, v, ldv,
eps, sfmin, tol, nsweep, work, lwork, info)
CGSVJ0 pre-processor for the routine cgesvj. subroutine dgsvj0
(jobv, m, n, a, lda, d, sva, mv, v, ldv, eps, sfmin, tol, nsweep, work,
lwork, info)
DGSVJ0 pre-processor for the routine dgesvj. subroutine sgsvj0
(jobv, m, n, a, lda, d, sva, mv, v, ldv, eps, sfmin, tol, nsweep, work,
lwork, info)
SGSVJ0 pre-processor for the routine sgesvj. subroutine zgsvj0
(jobv, m, n, a, lda, d, sva, mv, v, ldv, eps, sfmin, tol, nsweep, work,
lwork, info)
ZGSVJ0 pre-processor for the routine zgesvj.
Detailed Description¶
Function Documentation¶
subroutine cgsvj0 (character*1 jobv, integer m, integer n, complex, dimension( lda, * ) a, integer lda, complex, dimension( n ) d, real, dimension( n ) sva, integer mv, complex, dimension( ldv, * ) v, integer ldv, real eps, real sfmin, real tol, integer nsweep, complex, dimension( lwork ) work, integer lwork, integer info)¶
CGSVJ0 pre-processor for the routine cgesvj.
Purpose:
CGSVJ0 is called from CGESVJ as a pre-processor and that is its main
purpose. It applies Jacobi rotations in the same way as CGESVJ does, but
it does not check convergence (stopping criterion). Few tuning
parameters (marked by [TP]) are available for the implementer.
Parameters
JOBV
JOBV is CHARACTER*1
Specifies whether the output from this procedure is used
to compute the matrix V:
= 'V': the product of the Jacobi rotations is accumulated
by postmultiplying the N-by-N array V.
(See the description of V.)
= 'A': the product of the Jacobi rotations is accumulated
by postmultiplying the MV-by-N array V.
(See the descriptions of MV and V.)
= 'N': the Jacobi rotations are not accumulated.
M
M is INTEGER
The number of rows of the input matrix A. M >= 0.
N
N is INTEGER
The number of columns of the input matrix A.
M >= N >= 0.
A
A is COMPLEX array, dimension (LDA,N)
On entry, M-by-N matrix A, such that A*diag(D) represents
the input matrix.
On exit,
A_onexit * diag(D_onexit) represents the input matrix A*diag(D)
post-multiplied by a sequence of Jacobi rotations, where the
rotation threshold and the total number of sweeps are given in
TOL and NSWEEP, respectively.
(See the descriptions of D, TOL and NSWEEP.)
LDA
LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,M).
D
D is COMPLEX array, dimension (N)
The array D accumulates the scaling factors from the complex scaled
Jacobi rotations.
On entry, A*diag(D) represents the input matrix.
On exit, A_onexit*diag(D_onexit) represents the input matrix
post-multiplied by a sequence of Jacobi rotations, where the
rotation threshold and the total number of sweeps are given in
TOL and NSWEEP, respectively.
(See the descriptions of A, TOL and NSWEEP.)
SVA
SVA is REAL array, dimension (N)
On entry, SVA contains the Euclidean norms of the columns of
the matrix A*diag(D).
On exit, SVA contains the Euclidean norms of the columns of
the matrix A_onexit*diag(D_onexit).
MV
MV is INTEGER
If JOBV = 'A', then MV rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'N', then MV is not referenced.
V
V is COMPLEX array, dimension (LDV,N)
If JOBV = 'V' then N rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'A' then MV rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'N', then V is not referenced.
LDV
LDV is INTEGER
The leading dimension of the array V, LDV >= 1.
If JOBV = 'V', LDV >= N.
If JOBV = 'A', LDV >= MV.
EPS
EPS is REAL
EPS = SLAMCH('Epsilon')
SFMIN
SFMIN is REAL
SFMIN = SLAMCH('Safe Minimum')
TOL
TOL is REAL
TOL is the threshold for Jacobi rotations. For a pair
A(:,p), A(:,q) of pivot columns, the Jacobi rotation is
applied only if ABS(COS(angle(A(:,p),A(:,q)))) > TOL.
NSWEEP
NSWEEP is INTEGER
NSWEEP is the number of sweeps of Jacobi rotations to be
performed.
WORK
WORK is COMPLEX array, dimension (LWORK)
LWORK
LWORK is INTEGER
LWORK is the dimension of WORK. LWORK >= M.
INFO
INFO is INTEGER
= 0: successful exit.
< 0: if INFO = -i, then the i-th argument had an illegal value
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
CGSVJ0 is used just to enable CGESVJ to call a simplified
version of itself to work on a submatrix of the original matrix.
Contributor:
Zlatko Drmac (Zagreb, Croatia)
Bugs, Examples and Comments:
Please report all bugs and send interesting test examples
and comments to drmac@math.hr. Thank you.
subroutine dgsvj0 (character*1 jobv, integer m, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( n ) d, double precision, dimension( n ) sva, integer mv, double precision, dimension( ldv, * ) v, integer ldv, double precision eps, double precision sfmin, double precision tol, integer nsweep, double precision, dimension( lwork ) work, integer lwork, integer info)¶
DGSVJ0 pre-processor for the routine dgesvj.
Purpose:
DGSVJ0 is called from DGESVJ as a pre-processor and that is its main
purpose. It applies Jacobi rotations in the same way as DGESVJ does, but
it does not check convergence (stopping criterion). Few tuning
parameters (marked by [TP]) are available for the implementer.
Parameters
JOBV
JOBV is CHARACTER*1
Specifies whether the output from this procedure is used
to compute the matrix V:
= 'V': the product of the Jacobi rotations is accumulated
by postmultiplying the N-by-N array V.
(See the description of V.)
= 'A': the product of the Jacobi rotations is accumulated
by postmultiplying the MV-by-N array V.
(See the descriptions of MV and V.)
= 'N': the Jacobi rotations are not accumulated.
M
M is INTEGER
The number of rows of the input matrix A. M >= 0.
N
N is INTEGER
The number of columns of the input matrix A.
M >= N >= 0.
A
A is DOUBLE PRECISION array, dimension (LDA,N)
On entry, M-by-N matrix A, such that A*diag(D) represents
the input matrix.
On exit,
A_onexit * D_onexit represents the input matrix A*diag(D)
post-multiplied by a sequence of Jacobi rotations, where the
rotation threshold and the total number of sweeps are given in
TOL and NSWEEP, respectively.
(See the descriptions of D, TOL and NSWEEP.)
LDA
LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,M).
D
D is DOUBLE PRECISION array, dimension (N)
The array D accumulates the scaling factors from the fast scaled
Jacobi rotations.
On entry, A*diag(D) represents the input matrix.
On exit, A_onexit*diag(D_onexit) represents the input matrix
post-multiplied by a sequence of Jacobi rotations, where the
rotation threshold and the total number of sweeps are given in
TOL and NSWEEP, respectively.
(See the descriptions of A, TOL and NSWEEP.)
SVA
SVA is DOUBLE PRECISION array, dimension (N)
On entry, SVA contains the Euclidean norms of the columns of
the matrix A*diag(D).
On exit, SVA contains the Euclidean norms of the columns of
the matrix onexit*diag(D_onexit).
MV
MV is INTEGER
If JOBV = 'A', then MV rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'N', then MV is not referenced.
V
V is DOUBLE PRECISION array, dimension (LDV,N)
If JOBV = 'V' then N rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'A' then MV rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'N', then V is not referenced.
LDV
LDV is INTEGER
The leading dimension of the array V, LDV >= 1.
If JOBV = 'V', LDV >= N.
If JOBV = 'A', LDV >= MV.
EPS
EPS is DOUBLE PRECISION
EPS = DLAMCH('Epsilon')
SFMIN
SFMIN is DOUBLE PRECISION
SFMIN = DLAMCH('Safe Minimum')
TOL
TOL is DOUBLE PRECISION
TOL is the threshold for Jacobi rotations. For a pair
A(:,p), A(:,q) of pivot columns, the Jacobi rotation is
applied only if DABS(COS(angle(A(:,p),A(:,q)))) > TOL.
NSWEEP
NSWEEP is INTEGER
NSWEEP is the number of sweeps of Jacobi rotations to be
performed.
WORK
WORK is DOUBLE PRECISION array, dimension (LWORK)
LWORK
LWORK is INTEGER
LWORK is the dimension of WORK. LWORK >= M.
INFO
INFO is INTEGER
= 0: successful exit.
< 0: if INFO = -i, then the i-th argument had an illegal value
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
DGSVJ0 is used just to enable DGESVJ to call a simplified
version of itself to work on a submatrix of the original matrix.
Contributors:
Zlatko Drmac (Zagreb, Croatia) and Kresimir Veselic
(Hagen, Germany)
Bugs, Examples and Comments:
Please report all bugs and send interesting test examples
and comments to drmac@math.hr. Thank you.
subroutine sgsvj0 (character*1 jobv, integer m, integer n, real, dimension( lda, * ) a, integer lda, real, dimension( n ) d, real, dimension( n ) sva, integer mv, real, dimension( ldv, * ) v, integer ldv, real eps, real sfmin, real tol, integer nsweep, real, dimension( lwork ) work, integer lwork, integer info)¶
SGSVJ0 pre-processor for the routine sgesvj.
Purpose:
SGSVJ0 is called from SGESVJ as a pre-processor and that is its main
purpose. It applies Jacobi rotations in the same way as SGESVJ does, but
it does not check convergence (stopping criterion). Few tuning
parameters (marked by [TP]) are available for the implementer.
Parameters
JOBV
JOBV is CHARACTER*1
Specifies whether the output from this procedure is used
to compute the matrix V:
= 'V': the product of the Jacobi rotations is accumulated
by postmultiplying the N-by-N array V.
(See the description of V.)
= 'A': the product of the Jacobi rotations is accumulated
by postmultiplying the MV-by-N array V.
(See the descriptions of MV and V.)
= 'N': the Jacobi rotations are not accumulated.
M
M is INTEGER
The number of rows of the input matrix A. M >= 0.
N
N is INTEGER
The number of columns of the input matrix A.
M >= N >= 0.
A
A is REAL array, dimension (LDA,N)
On entry, M-by-N matrix A, such that A*diag(D) represents
the input matrix.
On exit,
A_onexit * D_onexit represents the input matrix A*diag(D)
post-multiplied by a sequence of Jacobi rotations, where the
rotation threshold and the total number of sweeps are given in
TOL and NSWEEP, respectively.
(See the descriptions of D, TOL and NSWEEP.)
LDA
LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,M).
D
D is REAL array, dimension (N)
The array D accumulates the scaling factors from the fast scaled
Jacobi rotations.
On entry, A*diag(D) represents the input matrix.
On exit, A_onexit*diag(D_onexit) represents the input matrix
post-multiplied by a sequence of Jacobi rotations, where the
rotation threshold and the total number of sweeps are given in
TOL and NSWEEP, respectively.
(See the descriptions of A, TOL and NSWEEP.)
SVA
SVA is REAL array, dimension (N)
On entry, SVA contains the Euclidean norms of the columns of
the matrix A*diag(D).
On exit, SVA contains the Euclidean norms of the columns of
the matrix onexit*diag(D_onexit).
MV
MV is INTEGER
If JOBV = 'A', then MV rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'N', then MV is not referenced.
V
V is REAL array, dimension (LDV,N)
If JOBV = 'V' then N rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'A' then MV rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'N', then V is not referenced.
LDV
LDV is INTEGER
The leading dimension of the array V, LDV >= 1.
If JOBV = 'V', LDV >= N.
If JOBV = 'A', LDV >= MV.
EPS
EPS is REAL
EPS = SLAMCH('Epsilon')
SFMIN
SFMIN is REAL
SFMIN = SLAMCH('Safe Minimum')
TOL
TOL is REAL
TOL is the threshold for Jacobi rotations. For a pair
A(:,p), A(:,q) of pivot columns, the Jacobi rotation is
applied only if ABS(COS(angle(A(:,p),A(:,q)))) > TOL.
NSWEEP
NSWEEP is INTEGER
NSWEEP is the number of sweeps of Jacobi rotations to be
performed.
WORK
WORK is REAL array, dimension (LWORK)
LWORK
LWORK is INTEGER
LWORK is the dimension of WORK. LWORK >= M.
INFO
INFO is INTEGER
= 0: successful exit.
< 0: if INFO = -i, then the i-th argument had an illegal value
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
SGSVJ0 is used just to enable SGESVJ to call a simplified
version of itself to work on a submatrix of the original matrix.
Contributors:
Zlatko Drmac (Zagreb, Croatia) and Kresimir Veselic
(Hagen, Germany)
Bugs, Examples and Comments:
Please report all bugs and send interesting test examples
and comments to drmac@math.hr. Thank you.
subroutine zgsvj0 (character*1 jobv, integer m, integer n, complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( n ) d, double precision, dimension( n ) sva, integer mv, complex*16, dimension( ldv, * ) v, integer ldv, double precision eps, double precision sfmin, double precision tol, integer nsweep, complex*16, dimension( lwork ) work, integer lwork, integer info)¶
ZGSVJ0 pre-processor for the routine zgesvj.
Purpose:
ZGSVJ0 is called from ZGESVJ as a pre-processor and that is its main
purpose. It applies Jacobi rotations in the same way as ZGESVJ does, but
it does not check convergence (stopping criterion). Few tuning
parameters (marked by [TP]) are available for the implementer.
Parameters
JOBV
JOBV is CHARACTER*1
Specifies whether the output from this procedure is used
to compute the matrix V:
= 'V': the product of the Jacobi rotations is accumulated
by postmultiplying the N-by-N array V.
(See the description of V.)
= 'A': the product of the Jacobi rotations is accumulated
by postmultiplying the MV-by-N array V.
(See the descriptions of MV and V.)
= 'N': the Jacobi rotations are not accumulated.
M
M is INTEGER
The number of rows of the input matrix A. M >= 0.
N
N is INTEGER
The number of columns of the input matrix A.
M >= N >= 0.
A
A is COMPLEX*16 array, dimension (LDA,N)
On entry, M-by-N matrix A, such that A*diag(D) represents
the input matrix.
On exit,
A_onexit * diag(D_onexit) represents the input matrix A*diag(D)
post-multiplied by a sequence of Jacobi rotations, where the
rotation threshold and the total number of sweeps are given in
TOL and NSWEEP, respectively.
(See the descriptions of D, TOL and NSWEEP.)
LDA
LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,M).
D
D is COMPLEX*16 array, dimension (N)
The array D accumulates the scaling factors from the complex scaled
Jacobi rotations.
On entry, A*diag(D) represents the input matrix.
On exit, A_onexit*diag(D_onexit) represents the input matrix
post-multiplied by a sequence of Jacobi rotations, where the
rotation threshold and the total number of sweeps are given in
TOL and NSWEEP, respectively.
(See the descriptions of A, TOL and NSWEEP.)
SVA
SVA is DOUBLE PRECISION array, dimension (N)
On entry, SVA contains the Euclidean norms of the columns of
the matrix A*diag(D).
On exit, SVA contains the Euclidean norms of the columns of
the matrix A_onexit*diag(D_onexit).
MV
MV is INTEGER
If JOBV = 'A', then MV rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'N', then MV is not referenced.
V
V is COMPLEX*16 array, dimension (LDV,N)
If JOBV = 'V' then N rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'A' then MV rows of V are post-multiplied by a
sequence of Jacobi rotations.
If JOBV = 'N', then V is not referenced.
LDV
LDV is INTEGER
The leading dimension of the array V, LDV >= 1.
If JOBV = 'V', LDV >= N.
If JOBV = 'A', LDV >= MV.
EPS
EPS is DOUBLE PRECISION
EPS = DLAMCH('Epsilon')
SFMIN
SFMIN is DOUBLE PRECISION
SFMIN = DLAMCH('Safe Minimum')
TOL
TOL is DOUBLE PRECISION
TOL is the threshold for Jacobi rotations. For a pair
A(:,p), A(:,q) of pivot columns, the Jacobi rotation is
applied only if ABS(COS(angle(A(:,p),A(:,q)))) > TOL.
NSWEEP
NSWEEP is INTEGER
NSWEEP is the number of sweeps of Jacobi rotations to be
performed.
WORK
WORK is COMPLEX*16 array, dimension (LWORK)
LWORK
LWORK is INTEGER
LWORK is the dimension of WORK. LWORK >= M.
INFO
INFO is INTEGER
= 0: successful exit.
< 0: if INFO = -i, then the i-th argument had an illegal value
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
ZGSVJ0 is used just to enable ZGESVJ to call a simplified
version of itself to work on a submatrix of the original matrix.
Contributor: Zlatko Drmac (Zagreb, Croatia)
Bugs, Examples and Comments:
Please report all bugs and send interesting test examples
and comments to drmac@math.hr. Thank you.
Author¶
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