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

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.ti -1c
.RI "subroutine \fBcptcon\fP (N, D, E, ANORM, RCOND, RWORK, INFO)"
.br
.RI "\fI\fBCPTCON\fP \fP"
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.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine cptcon (integerN, real, dimension( * )D, complex, dimension( * )E, realANORM, realRCOND, real, dimension( * )RWORK, integerINFO)"

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\fBCPTCON\fP  
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\fBPurpose: \fP
.RS 4

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.nf
 CPTCON computes the reciprocal of the condition number (in the
 1-norm) of a complex Hermitian positive definite tridiagonal matrix
 using the factorization A = L*D*L**H or A = U**H*D*U computed by
 CPTTRF.

 Norm(inv(A)) is computed by a direct method, and the reciprocal of
 the condition number is computed as
                  RCOND = 1 / (ANORM * norm(inv(A))).
.fi
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.RE
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\fBParameters:\fP
.RS 4
\fIN\fP 
.PP
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          N is INTEGER
          The order of the matrix A.  N >= 0.
.fi
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\fID\fP 
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          D is REAL array, dimension (N)
          The n diagonal elements of the diagonal matrix D from the
          factorization of A, as computed by CPTTRF.
.fi
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\fIE\fP 
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.nf
          E is COMPLEX array, dimension (N-1)
          The (n-1) off-diagonal elements of the unit bidiagonal factor
          U or L from the factorization of A, as computed by CPTTRF.
.fi
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\fIANORM\fP 
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          ANORM is REAL
          The 1-norm of the original matrix A.
.fi
.PP
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\fIRCOND\fP 
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          RCOND is REAL
          The reciprocal of the condition number of the matrix A,
          computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is the
          1-norm of inv(A) computed in this routine.
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\fIRWORK\fP 
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          RWORK is REAL array, dimension (N)
.fi
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\fIINFO\fP 
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          INFO is INTEGER
          = 0:  successful exit
          < 0:  if INFO = -i, the i-th argument had an illegal value
.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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\fBFurther Details: \fP
.RS 4

.PP
.nf
  The method used is described in Nicholas J. Higham, "Efficient
  Algorithms for Computing the Condition Number of a Tridiagonal
  Matrix", SIAM J. Sci. Stat. Comput., Vol. 7, No. 1, January 1986.
.fi
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.RE
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Definition at line 120 of file cptcon\&.f\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for LAPACK from the source code\&.