TESTING/EIG/dsvdct.f(3)

NAME
TESTING/EIG/dsvdct.f

SYNOPSIS

  Functions/Subroutines
subroutine dsvdct (n, s, e, shift, num)
DSVDCT

Function/Subroutine Documentation

  subroutine dsvdct (integer n, double precision, dimension( * ) s, double precision, dimension( * ) e, double precision shift, integer num)

DSVDCT

Purpose:

    !>
    !> DSVDCT counts the number NUM of eigenvalues of a 2*N by 2*N
    !> tridiagonal matrix T which are less than or equal to SHIFT.  T is
    !> formed by putting zeros on the diagonal and making the off-diagonals
    !> equal to S(1), E(1), S(2), E(2), ... , E(N-1), S(N).  If SHIFT is
    !> positive, NUM is equal to N plus the number of singular values of a
    !> bidiagonal matrix B less than or equal to SHIFT.  Here B has diagonal
    !> entries S(1), ..., S(N) and superdiagonal entries E(1), ... E(N-1).
    !> If SHIFT is negative, NUM is equal to the number of singular values
    !> of B greater than or equal to -SHIFT.
    !>
    !> See W. Kahan , Report CS41, Computer Science Dept., Stanford University,
    !> July 21, 1966
    !>

Parameters
    N

    !>          N is INTEGER
    !>          The dimension of the bidiagonal matrix B.
    !>

    S

    !>          S is DOUBLE PRECISION array, dimension (N)
    !>          The diagonal entries of the bidiagonal matrix B.
    !>

    E

    !>          E is DOUBLE PRECISION array of dimension (N-1)
    !>          The superdiagonal entries of the bidiagonal matrix B.
    !>

    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 86 of file dsvdct.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.