.TH DLARRC 1 "November 2006" " LAPACK auxiliary routine (version 3.1) " " LAPACK auxiliary routine (version 3.1) " .SH NAME DLARRC - number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] if JOBT = \(aqT\(aq, and of L D L^T if JOBT = \(aqL\(aq .SH SYNOPSIS .TP 19 SUBROUTINE DLARRC( JOBT, N, VL, VU, D, E, PIVMIN, EIGCNT, LCNT, RCNT, INFO ) .TP 19 .ti +4 CHARACTER JOBT .TP 19 .ti +4 INTEGER EIGCNT, INFO, LCNT, N, RCNT .TP 19 .ti +4 DOUBLE PRECISION PIVMIN, VL, VU .TP 19 .ti +4 DOUBLE PRECISION D( * ), E( * ) .SH PURPOSE Find the number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] if JOBT = \(aqT\(aq, and of L D L^T if JOBT = \(aqL\(aq. .SH ARGUMENTS .TP 8 JOBT (input) CHARACTER*1 = \(aqT\(aq: Compute Sturm count for matrix T. .br = \(aqL\(aq: Compute Sturm count for matrix L D L^T. .TP 8 N (input) INTEGER The order of the matrix. N > 0. .TP 8 VL (input) DOUBLE PRECISION VU (input) DOUBLE PRECISION The lower and upper bounds for the eigenvalues. .TP 8 D (input) DOUBLE PRECISION array, dimension (N) JOBT = \(aqT\(aq: The N diagonal elements of the tridiagonal matrix T. .br JOBT = \(aqL\(aq: The N diagonal elements of the diagonal matrix D. .TP 8 E (input) DOUBLE PRECISION array, dimension (N) .br JOBT = \(aqT\(aq: The N-1 offdiagonal elements of the matrix T. .br JOBT = \(aqL\(aq: The N-1 offdiagonal elements of the matrix L. .TP 8 PIVMIN (input) DOUBLE PRECISION The minimum pivot in the Sturm sequence for T. .TP 8 EIGCNT (output) INTEGER The number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] .TP 8 LCNT (output) INTEGER RCNT (output) INTEGER The left and right negcounts of the interval. .TP 8 INFO (output) INTEGER .SH FURTHER DETAILS Based on contributions by .br Beresford Parlett, University of California, Berkeley, USA Jim Demmel, University of California, Berkeley, USA .br Inderjit Dhillon, University of Texas, Austin, USA .br Osni Marques, LBNL/NERSC, USA .br Christof Voemel, University of California, Berkeley, USA