.TH "SRC/zgsvj0.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*-
.ad l
.nh
.SH NAME
SRC/zgsvj0.f
.SH SYNOPSIS
.br
.PP
.SS "Functions/Subroutines"

.in +1c
.ti -1c
.RI "subroutine \fBzgsvj0\fP (jobv, m, n, a, lda, d, sva, mv, v, ldv, eps, sfmin, tol, nsweep, work, lwork, info)"
.br
.RI "\fB ZGSVJ0 pre-processor for the routine zgesvj\&. \fP "
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "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)"

.PP
\fB ZGSVJ0 pre-processor for the routine zgesvj\&. \fP  
.PP
\fBPurpose:\fP
.RS 4

.PP
.nf
!>
!> 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\&.
!> 
.fi
.PP
 
.RE
.PP
\fBParameters\fP
.RS 4
\fIJOBV\fP 
.PP
.nf
!>          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\&.
!> 
.fi
.PP
.br
\fIM\fP 
.PP
.nf
!>          M is INTEGER
!>          The number of rows of the input matrix A\&.  M >= 0\&.
!> 
.fi
.PP
.br
\fIN\fP 
.PP
.nf
!>          N is INTEGER
!>          The number of columns of the input matrix A\&.
!>          M >= N >= 0\&.
!> 
.fi
.PP
.br
\fIA\fP 
.PP
.nf
!>          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\&.)
!> 
.fi
.PP
.br
\fILDA\fP 
.PP
.nf
!>          LDA is INTEGER
!>          The leading dimension of the array A\&.  LDA >= max(1,M)\&.
!> 
.fi
.PP
.br
\fID\fP 
.PP
.nf
!>          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\&.)
!> 
.fi
.PP
.br
\fISVA\fP 
.PP
.nf
!>          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)\&.
!> 
.fi
.PP
.br
\fIMV\fP 
.PP
.nf
!>          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\&.
!> 
.fi
.PP
.br
\fIV\fP 
.PP
.nf
!>          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\&.
!> 
.fi
.PP
.br
\fILDV\fP 
.PP
.nf
!>          LDV is INTEGER
!>          The leading dimension of the array V,  LDV >= 1\&.
!>          If JOBV = 'V', LDV >= N\&.
!>          If JOBV = 'A', LDV >= MV\&.
!> 
.fi
.PP
.br
\fIEPS\fP 
.PP
.nf
!>          EPS is DOUBLE PRECISION
!>          EPS = DLAMCH('Epsilon')
!> 
.fi
.PP
.br
\fISFMIN\fP 
.PP
.nf
!>          SFMIN is DOUBLE PRECISION
!>          SFMIN = DLAMCH('Safe Minimum')
!> 
.fi
.PP
.br
\fITOL\fP 
.PP
.nf
!>          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\&.
!> 
.fi
.PP
.br
\fINSWEEP\fP 
.PP
.nf
!>          NSWEEP is INTEGER
!>          NSWEEP is the number of sweeps of Jacobi rotations to be
!>          performed\&.
!> 
.fi
.PP
.br
\fIWORK\fP 
.PP
.nf
!>          WORK is COMPLEX*16 array, dimension (LWORK)
!> 
.fi
.PP
.br
\fILWORK\fP 
.PP
.nf
!>          LWORK is INTEGER
!>          LWORK is the dimension of WORK\&. LWORK >= M\&.
!> 
.fi
.PP
.br
\fIINFO\fP 
.PP
.nf
!>          INFO is INTEGER
!>          = 0:  successful exit\&.
!>          < 0:  if INFO = -i, then the i-th argument had an illegal value
!> 
.fi
.PP
 
.RE
.PP
\fBAuthor\fP
.RS 4
Univ\&. of Tennessee 

.PP
Univ\&. of California Berkeley 

.PP
Univ\&. of Colorado Denver 

.PP
NAG Ltd\&.
.RE
.PP
\fBFurther Details:\fP
.RS 4
ZGSVJ0 is used just to enable ZGESVJ to call a simplified version of itself to work on a submatrix of the original matrix\&.
.RE
.PP
Contributor: Zlatko Drmac (Zagreb, Croatia)

.PP
\fBBugs, Examples and Comments:\fP
.RS 4
Please report all bugs and send interesting test examples and comments to drmac@math.hr\&. Thank you\&. 
.RE
.PP

.PP
Definition at line \fB216\fP of file \fBzgsvj0\&.f\fP\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for LAPACK from the source code\&.