dlasq4(3F)

NAME
     DLASQ4 - DLASQ4 estimates TAU, the smallest eigenvalue of a matrix

SYNOPSIS
     SUBROUTINE DLASQ4( N, Q, E, TAU, SUP )

         INTEGER        N

         DOUBLE         PRECISION SUP, TAU

         DOUBLE         PRECISION E( * ), Q( * )

PURPOSE
        DLASQ4 estimates TAU, the smallest eigenvalue of a matrix. This
        routine improves the input value of SUP which is an upper bound
        for the smallest eigenvalue for this matrix .


ARGUMENTS
     N       (input) INTEGER
             On entry, N specifies the number of rows and columns in the
             matrix. N must be at least 0.

     Q       (input) DOUBLE PRECISION array, dimension (N)
             Q array

     E       (input) DOUBLE PRECISION array, dimension (N)
             E array

     TAU     (output) DOUBLE PRECISION
             Estimate of the shift

     SUP     (input/output) DOUBLE PRECISION
             Upper bound for the smallest singular value