# slarrc.f - Man Page

SRC/slarrc.f

## Synopsis

### Functions/Subroutines

subroutine **slarrc** (jobt, n, vl, vu, d, e, pivmin, eigcnt, lcnt, rcnt, info)**SLARRC** computes the number of eigenvalues of the symmetric tridiagonal matrix.

## Function/Subroutine Documentation

### subroutine slarrc (character jobt, integer n, real vl, real vu, real, dimension( * ) d, real, dimension( * ) e, real pivmin, integer eigcnt, integer lcnt, integer rcnt, integer info)

**SLARRC** 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 REAL The lower bound for the eigenvalues.

*VU*VU is REAL The upper bound for the eigenvalues.

*D*D is REAL 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 REAL 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 REAL 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 **slarrc.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page slarrc(3) is an alias of slarrc.f(3).