dlarrc.f - Man Page
SRC/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 (character jobt, integer n, double precision vl, double precision vu, double precision, dimension( * ) d, double precision, dimension( * ) e, double precision pivmin, integer eigcnt, integer lcnt, integer rcnt, integer info)
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 The lower bound for the eigenvalues.
VU
VU is DOUBLE PRECISION The upper bound 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.
- 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 135 of file dlarrc.f.
Author
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Referenced By
The man page dlarrc(3) is an alias of dlarrc.f(3).