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dlarrc.f(3) LAPACK dlarrc.f(3)

NAME

dlarrc.f -

SYNOPSIS

Functions/Subroutines


subroutine dlarrc (JOBT, N, VL, VU, D, E, PIVMIN, EIGCNT, LCNT, RCNT, INFO)
 
DLARRC computes the number of eigenvalues of the symmetric tridiagonal matrix.

Function/Subroutine Documentation

subroutine dlarrc (characterJOBT, integerN, double precisionVL, double precisionVU, double precision, dimension( * )D, double precision, dimension( * )E, double precisionPIVMIN, integerEIGCNT, integerLCNT, integerRCNT, integerINFO)

DLARRC computes the number of eigenvalues of the symmetric tridiagonal matrix.
Purpose:
 Find the number of eigenvalues of the symmetric tridiagonal matrix T
 that are in the interval (VL,VU] if JOBT = 'T', and of L D L^T
 if JOBT = 'L'.
Parameters:
JOBT
          JOBT is CHARACTER*1
          = 'T':  Compute Sturm count for matrix T.
          = 'L':  Compute Sturm count for matrix L D L^T.
N
          N is INTEGER
          The order of the matrix. N > 0.
VL
          VL is DOUBLE PRECISION
VU
          VU is DOUBLE PRECISION
          The lower and upper bounds for the eigenvalues.
D
          D is DOUBLE PRECISION array, dimension (N)
          JOBT = 'T': The N diagonal elements of the tridiagonal matrix T.
          JOBT = 'L': The N diagonal elements of the diagonal matrix D.
E
          E is DOUBLE PRECISION array, dimension (N)
          JOBT = 'T': The N-1 offdiagonal elements of the matrix T.
          JOBT = 'L': The N-1 offdiagonal elements of the matrix L.
PIVMIN
          PIVMIN is DOUBLE PRECISION
          The minimum pivot in the Sturm sequence for T.
EIGCNT
          EIGCNT is INTEGER
          The number of eigenvalues of the symmetric tridiagonal matrix T
          that are in the interval (VL,VU]
LCNT
          LCNT is INTEGER
RCNT
          RCNT is INTEGER
          The left and right negcounts of the interval.
INFO
          INFO is INTEGER
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
September 2012
Contributors:
Beresford Parlett, University of California, Berkeley, USA
 

Jim Demmel, University of California, Berkeley, USA
 

Inderjit Dhillon, University of Texas, Austin, USA
 

Osni Marques, LBNL/NERSC, USA
 

Christof Voemel, University of California, Berkeley, USA
Definition at line 136 of file dlarrc.f.

Author

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Wed Oct 15 2014 Version 3.4.2