dlarrc (l)  Linux Man Pages
dlarrc: the number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] if JOBT = aqTaq, and of L D L^T if JOBT = aqLaq
NAME
DLARRC  the number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] if JOBT = aqTaq, and of L D L^T if JOBT = aqLaqSYNOPSIS
 SUBROUTINE DLARRC(
 JOBT, N, VL, VU, D, E, PIVMIN, EIGCNT, LCNT, RCNT, INFO )
 CHARACTER JOBT
 INTEGER EIGCNT, INFO, LCNT, N, RCNT
 DOUBLE PRECISION PIVMIN, VL, VU
 DOUBLE PRECISION D( * ), E( * )
PURPOSE
Find the number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] if JOBT = aqTaq, and of L D L^T if JOBT = aqLaq.ARGUMENTS
 JOBT (input) CHARACTER*1

= aqTaq: Compute Sturm count for matrix T.
= aqLaq: Compute Sturm count for matrix L D L^T.  N (input) INTEGER
 The order of the matrix. N > 0.
 VL (input) DOUBLE PRECISION
 VU (input) DOUBLE PRECISION The lower and upper bounds for the eigenvalues.
 D (input) DOUBLE PRECISION array, dimension (N)

JOBT = aqTaq: The N diagonal elements of the tridiagonal matrix T.
JOBT = aqLaq: The N diagonal elements of the diagonal matrix D.  E (input) DOUBLE PRECISION array, dimension (N)

JOBT = aqTaq: The N1 offdiagonal elements of the matrix T.
JOBT = aqLaq: The N1 offdiagonal elements of the matrix L.  PIVMIN (input) DOUBLE PRECISION
 The minimum pivot in the Sturm sequence for T.
 EIGCNT (output) INTEGER
 The number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU]
 LCNT (output) INTEGER
 RCNT (output) INTEGER The left and right negcounts of the interval.
 INFO (output) INTEGER
FURTHER DETAILS
Based on contributions byBeresford 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