.TH "slasd5.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*-
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.SH NAME
slasd5.f \- 
.SH SYNOPSIS
.br
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.SS "Functions/Subroutines"

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.RI "subroutine \fBslasd5\fP (I, D, Z, DELTA, RHO, DSIGMA, WORK)"
.br
.RI "\fI\fBSLASD5\fP computes the square root of the i-th eigenvalue of a positive symmetric rank-one modification of a 2-by-2 diagonal matrix\&. Used by sbdsdc\&. \fP"
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.SH "Function/Subroutine Documentation"
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.SS "subroutine slasd5 (integerI, real, dimension( 2 )D, real, dimension( 2 )Z, real, dimension( 2 )DELTA, realRHO, realDSIGMA, real, dimension( 2 )WORK)"

.PP
\fBSLASD5\fP computes the square root of the i-th eigenvalue of a positive symmetric rank-one modification of a 2-by-2 diagonal matrix\&. Used by sbdsdc\&.  
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\fBPurpose: \fP
.RS 4

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.nf
 This subroutine computes the square root of the I-th eigenvalue
 of a positive symmetric rank-one modification of a 2-by-2 diagonal
 matrix

            diag( D ) * diag( D ) +  RHO * Z * transpose(Z) .

 The diagonal entries in the array D are assumed to satisfy

            0 <= D(i) < D(j)  for  i < j .

 We also assume RHO > 0 and that the Euclidean norm of the vector
 Z is one.
.fi
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.RE
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\fBParameters:\fP
.RS 4
\fII\fP 
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          I is INTEGER
         The index of the eigenvalue to be computed.  I = 1 or I = 2.
.fi
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\fID\fP 
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          D is REAL array, dimension (2)
         The original eigenvalues.  We assume 0 <= D(1) < D(2).
.fi
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\fIZ\fP 
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          Z is REAL array, dimension (2)
         The components of the updating vector.
.fi
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\fIDELTA\fP 
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          DELTA is REAL array, dimension (2)
         Contains (D(j) - sigma_I) in its  j-th component.
         The vector DELTA contains the information necessary
         to construct the eigenvectors.
.fi
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\fIRHO\fP 
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          RHO is REAL
         The scalar in the symmetric updating formula.
.fi
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\fIDSIGMA\fP 
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          DSIGMA is REAL
         The computed sigma_I, the I-th updated eigenvalue.
.fi
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\fIWORK\fP 
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          WORK is REAL array, dimension (2)
         WORK contains (D(j) + sigma_I) in its  j-th component.
.fi
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.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
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\fBContributors: \fP
.RS 4
Ren-Cang Li, Computer Science Division, University of California at Berkeley, USA 
.RE
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Definition at line 117 of file slasd5\&.f\&.
.SH "Author"
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Generated automatically by Doxygen for LAPACK from the source code\&.