.TH "dlaein.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*-
.ad l
.nh
.SH NAME
dlaein.f \- 
.SH SYNOPSIS
.br
.PP
.SS "Functions/Subroutines"

.in +1c
.ti -1c
.RI "subroutine \fBdlaein\fP (RIGHTV, NOINIT, N, H, LDH, WR, WI, VR, VI, B, LDB, WORK, EPS3, SMLNUM, BIGNUM, INFO)"
.br
.RI "\fI\fBDLAEIN\fP computes a specified right or left eigenvector of an upper Hessenberg matrix by inverse iteration\&. \fP"
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine dlaein (logicalRIGHTV, logicalNOINIT, integerN, double precision, dimension( ldh, * )H, integerLDH, double precisionWR, double precisionWI, double precision, dimension( * )VR, double precision, dimension( * )VI, double precision, dimension( ldb, * )B, integerLDB, double precision, dimension( * )WORK, double precisionEPS3, double precisionSMLNUM, double precisionBIGNUM, integerINFO)"

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

.PP
.nf
 DLAEIN uses inverse iteration to find a right or left eigenvector
 corresponding to the eigenvalue (WR,WI) of a real upper Hessenberg
 matrix H.
.fi
.PP
 
.RE
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\fBParameters:\fP
.RS 4
\fIRIGHTV\fP 
.PP
.nf
          RIGHTV is LOGICAL
          = .TRUE. : compute right eigenvector;
          = .FALSE.: compute left eigenvector.
.fi
.PP
.br
\fINOINIT\fP 
.PP
.nf
          NOINIT is LOGICAL
          = .TRUE. : no initial vector supplied in (VR,VI).
          = .FALSE.: initial vector supplied in (VR,VI).
.fi
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.br
\fIN\fP 
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          N is INTEGER
          The order of the matrix H.  N >= 0.
.fi
.PP
.br
\fIH\fP 
.PP
.nf
          H is DOUBLE PRECISION array, dimension (LDH,N)
          The upper Hessenberg matrix H.
.fi
.PP
.br
\fILDH\fP 
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.nf
          LDH is INTEGER
          The leading dimension of the array H.  LDH >= max(1,N).
.fi
.PP
.br
\fIWR\fP 
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          WR is DOUBLE PRECISION
.fi
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.br
\fIWI\fP 
.PP
.nf
          WI is DOUBLE PRECISION
          The real and imaginary parts of the eigenvalue of H whose
          corresponding right or left eigenvector is to be computed.
.fi
.PP
.br
\fIVR\fP 
.PP
.nf
          VR is DOUBLE PRECISION array, dimension (N)
.fi
.PP
.br
\fIVI\fP 
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          VI is DOUBLE PRECISION array, dimension (N)
          On entry, if NOINIT = .FALSE. and WI = 0.0, VR must contain
          a real starting vector for inverse iteration using the real
          eigenvalue WR; if NOINIT = .FALSE. and WI.ne.0.0, VR and VI
          must contain the real and imaginary parts of a complex
          starting vector for inverse iteration using the complex
          eigenvalue (WR,WI); otherwise VR and VI need not be set.
          On exit, if WI = 0.0 (real eigenvalue), VR contains the
          computed real eigenvector; if WI.ne.0.0 (complex eigenvalue),
          VR and VI contain the real and imaginary parts of the
          computed complex eigenvector. The eigenvector is 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|.
          VI is not referenced if WI = 0.0.
.fi
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.br
\fIB\fP 
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          B is DOUBLE PRECISION array, dimension (LDB,N)
.fi
.PP
.br
\fILDB\fP 
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.nf
          LDB is INTEGER
          The leading dimension of the array B.  LDB >= N+1.
.fi
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.br
\fIWORK\fP 
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.nf
          WORK is DOUBLE PRECISION array, dimension (N)
.fi
.PP
.br
\fIEPS3\fP 
.PP
.nf
          EPS3 is DOUBLE PRECISION
          A small machine-dependent value which is used to perturb
          close eigenvalues, and to replace zero pivots.
.fi
.PP
.br
\fISMLNUM\fP 
.PP
.nf
          SMLNUM is DOUBLE PRECISION
          A machine-dependent value close to the underflow threshold.
.fi
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.br
\fIBIGNUM\fP 
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.nf
          BIGNUM is DOUBLE PRECISION
          A machine-dependent value close to the overflow threshold.
.fi
.PP
.br
\fIINFO\fP 
.PP
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          INFO is INTEGER
          = 0:  successful exit
          = 1:  inverse iteration did not converge; VR is set to the
                last iterate, and so is VI if WI.ne.0.0.
.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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\fBDate:\fP
.RS 4
September 2012 
.RE
.PP

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Definition at line 172 of file dlaein\&.f\&.
.SH "Author"
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Generated automatically by Doxygen for LAPACK from the source code\&.