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

.in +1c
.ti -1c
.RI "subroutine \fBdlarra\fP (N, D, E, E2, SPLTOL, TNRM, NSPLIT, ISPLIT, INFO)"
.br
.RI "\fI\fBDLARRA\fP computes the splitting points with the specified threshold\&. \fP"
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine dlarra (integerN, double precision, dimension( * )D, double precision, dimension( * )E, double precision, dimension( * )E2, double precisionSPLTOL, double precisionTNRM, integerNSPLIT, integer, dimension( * )ISPLIT, integerINFO)"

.PP
\fBDLARRA\fP computes the splitting points with the specified threshold\&.  
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\fBPurpose: \fP
.RS 4

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.nf
 Compute the splitting points with threshold SPLTOL.
 DLARRA sets any "small" off-diagonal elements to zero.
.fi
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.RE
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\fBParameters:\fP
.RS 4
\fIN\fP 
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          N is INTEGER
          The order of the matrix. N > 0.
.fi
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.br
\fID\fP 
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          D is DOUBLE PRECISION array, dimension (N)
          On entry, the N diagonal elements of the tridiagonal
          matrix T.
.fi
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\fIE\fP 
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.nf
          E is DOUBLE PRECISION array, dimension (N)
          On entry, the first (N-1) entries contain the subdiagonal
          elements of the tridiagonal matrix T; E(N) need not be set.
          On exit, the entries E( ISPLIT( I ) ), 1 <= I <= NSPLIT,
          are set to zero, the other entries of E are untouched.
.fi
.PP
.br
\fIE2\fP 
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.nf
          E2 is DOUBLE PRECISION array, dimension (N)
          On entry, the first (N-1) entries contain the SQUARES of the
          subdiagonal elements of the tridiagonal matrix T;
          E2(N) need not be set.
          On exit, the entries E2( ISPLIT( I ) ),
          1 <= I <= NSPLIT, have been set to zero
.fi
.PP
.br
\fISPLTOL\fP 
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          SPLTOL is DOUBLE PRECISION
          The threshold for splitting. Two criteria can be used:
          SPLTOL<0 : criterion based on absolute off-diagonal value
          SPLTOL>0 : criterion that preserves relative accuracy
.fi
.PP
.br
\fITNRM\fP 
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          TNRM is DOUBLE PRECISION
          The norm of the matrix.
.fi
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\fINSPLIT\fP 
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          NSPLIT is INTEGER
          The number of blocks T splits into. 1 <= NSPLIT <= N.
.fi
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\fIISPLIT\fP 
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          ISPLIT is INTEGER array, dimension (N)
          The splitting points, at which T breaks up into blocks.
          The first block consists of rows/columns 1 to ISPLIT(1),
          the second of rows/columns ISPLIT(1)+1 through ISPLIT(2),
          etc., and the NSPLIT-th consists of rows/columns
          ISPLIT(NSPLIT-1)+1 through ISPLIT(NSPLIT)=N.
.fi
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.br
\fIINFO\fP 
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          INFO is INTEGER
          = 0:  successful exit
.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 
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\fBContributors: \fP
.RS 4
Beresford Parlett, University of California, Berkeley, USA 
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 Jim Demmel, University of California, Berkeley, USA 
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 Inderjit Dhillon, University of Texas, Austin, USA 
.br
 Osni Marques, LBNL/NERSC, USA 
.br
 Christof Voemel, University of California, Berkeley, USA 
.RE
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Definition at line 136 of file dlarra\&.f\&.
.SH "Author"
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Generated automatically by Doxygen for LAPACK from the source code\&.