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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/dstect.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/dstect.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/dstect.f

SYNOPSIS

Functions/Subroutines


subroutine DSTECT (n, a, b, shift, num)
DSTECT

Function/Subroutine Documentation

subroutine DSTECT (integer n, double precision, dimension( * ) a, double precision, dimension( * ) b, double precision shift, integer num)

DSTECT

Purpose:

!>
!>    DSTECT counts the number NUM of eigenvalues of a tridiagonal
!>    matrix T which are less than or equal to SHIFT. T has
!>    diagonal entries A(1), ... , A(N), and offdiagonal entries
!>    B(1), ..., B(N-1).
!>    See W. Kahan , Report CS41, Computer Science Dept., Stanford
!>    University, July 21, 1966
!>

Parameters

N 

!>          N is INTEGER
!>          The dimension of the tridiagonal matrix T.
!>

A

!>          A is DOUBLE PRECISION array, dimension (N)
!>          The diagonal entries of the tridiagonal matrix T.
!>

B

!>          B is DOUBLE PRECISION array, dimension (N-1)
!>          The offdiagonal entries of the tridiagonal matrix T.
!>

SHIFT

!>          SHIFT is DOUBLE PRECISION
!>          The shift, used as described under Purpose.
!>

NUM

!>          NUM is INTEGER
!>          The number of eigenvalues of T less than or equal
!>          to SHIFT.
!>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 81 of file dstect.f.

Author

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Version 3.12.0 LAPACK