TESTING/EIG/ssvdct.f(3)    Library Functions Manual    TESTING/EIG/ssvdct.f(3)

NAME
       TESTING/EIG/ssvdct.f

SYNOPSIS
   Functions/Subroutines
       subroutine ssvdct (n, s, e, shift, num)
           SSVDCT

Function/Subroutine Documentation
   subroutine ssvdct (integer n, real, dimension( * ) s, real, dimension( * )
       e, real shift, integer num)
       SSVDCT

       Purpose:


            SSVDCT 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 'Accurate Eigenvalues of a Symmetric Tridiagonal
            Matrix', 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 REAL array, dimension (N)
                     The diagonal entries of the bidiagonal matrix B.

           E

                     E is REAL array of dimension (N-1)
                     The superdiagonal entries of the bidiagonal matrix B.

           SHIFT

                     SHIFT is REAL
                     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 ssvdct.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0         TESTING/EIG/ssvdct.f(3)