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

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.ti -1c
.RI "subroutine \fBzlaein\fP (rightv, noinit, n, h, ldh, w, v, b, ldb, rwork, eps3, smlnum, info)"
.br
.RI "\fBZLAEIN\fP computes a specified right or left eigenvector of an upper Hessenberg matrix by inverse iteration\&. "
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine zlaein (logical rightv, logical noinit, integer n, complex*16, dimension( ldh, * ) h, integer ldh, complex*16 w, complex*16, dimension( * ) v, complex*16, dimension( ldb, * ) b, integer ldb, double precision, dimension( * ) rwork, double precision eps3, double precision smlnum, integer info)"

.PP
\fBZLAEIN\fP computes a specified right or left eigenvector of an upper Hessenberg matrix by inverse iteration\&.  
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\fBPurpose:\fP
.RS 4

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.nf
 ZLAEIN uses inverse iteration to find a right or left eigenvector
 corresponding to the eigenvalue W of a complex upper Hessenberg
 matrix H\&.
.fi
.PP
 
.RE
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\fBParameters\fP
.RS 4
\fIRIGHTV\fP 
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.nf
          RIGHTV is LOGICAL
          = \&.TRUE\&. : compute right eigenvector;
          = \&.FALSE\&.: compute left eigenvector\&.
.fi
.PP
.br
\fINOINIT\fP 
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.nf
          NOINIT is LOGICAL
          = \&.TRUE\&. : no initial vector supplied in V
          = \&.FALSE\&.: initial vector supplied in V\&.
.fi
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\fIN\fP 
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          N is INTEGER
          The order of the matrix H\&.  N >= 0\&.
.fi
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\fIH\fP 
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          H is COMPLEX*16 array, dimension (LDH,N)
          The upper Hessenberg matrix H\&.
.fi
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\fILDH\fP 
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          LDH is INTEGER
          The leading dimension of the array H\&.  LDH >= max(1,N)\&.
.fi
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\fIW\fP 
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          W is COMPLEX*16
          The eigenvalue of H whose corresponding right or left
          eigenvector is to be computed\&.
.fi
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.br
\fIV\fP 
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          V is COMPLEX*16 array, dimension (N)
          On entry, if NOINIT = \&.FALSE\&., V must contain a starting
          vector for inverse iteration; otherwise V need not be set\&.
          On exit, V contains the computed eigenvector, normalized so
          that the component of largest magnitude has magnitude 1; here
          the magnitude of a complex number (x,y) is taken to be
          |x| + |y|\&.
.fi
.PP
.br
\fIB\fP 
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          B is COMPLEX*16 array, dimension (LDB,N)
.fi
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\fILDB\fP 
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          LDB is INTEGER
          The leading dimension of the array B\&.  LDB >= max(1,N)\&.
.fi
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.br
\fIRWORK\fP 
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          RWORK is DOUBLE PRECISION array, dimension (N)
.fi
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\fIEPS3\fP 
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          EPS3 is DOUBLE PRECISION
          A small machine-dependent value which is used to perturb
          close eigenvalues, and to replace zero pivots\&.
.fi
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.br
\fISMLNUM\fP 
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          SMLNUM is DOUBLE PRECISION
          A machine-dependent value close to the underflow threshold\&.
.fi
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.br
\fIINFO\fP 
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          INFO is INTEGER
          = 0:  successful exit
          = 1:  inverse iteration did not converge; V is set to the
                last iterate\&.
.fi
.PP
 
.RE
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\fBAuthor\fP
.RS 4
Univ\&. of Tennessee 
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Univ\&. of California Berkeley 
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Univ\&. of Colorado Denver 
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NAG Ltd\&. 
.RE
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Definition at line \fB147\fP of file \fBzlaein\&.f\fP\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for LAPACK from the source code\&.