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      SUBROUTINE DLABAD( SMALL, LARGE )

*

*  -- LAPACK auxiliary routine (version 3.2) --

*  -- LAPACK is a software package provided by Univ. of Tennessee,    --

*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--

*     November 2006

*

*     .. Scalar Arguments ..

      DOUBLE PRECISION   LARGE, SMALL

*     ..

*

*  Purpose

*  =======

*

*  DLABAD takes as input the values computed by DLAMCH for underflow and

*  overflow, and returns the square root of each of these values if the

*  log of LARGE is sufficiently large.  This subroutine is intended to

*  identify machines with a large exponent range, such as the Crays, and

*  redefine the underflow and overflow limits to be the square roots of

*  the values computed by DLAMCH.  This subroutine is needed because

*  DLAMCH does not compensate for poor arithmetic in the upper half of

*  the exponent range, as is found on a Cray.

*

*  Arguments

*  =========

*

*  SMALL   (input/output) DOUBLE PRECISION

*          On entry, the underflow threshold as computed by DLAMCH.

*          On exit, if LOG10(LARGE) is sufficiently large, the square

*          root of SMALL, otherwise unchanged.

*

*  LARGE   (input/output) DOUBLE PRECISION

*          On entry, the overflow threshold as computed by DLAMCH.

*          On exit, if LOG10(LARGE) is sufficiently large, the square

*          root of LARGE, otherwise unchanged.

*

*  =====================================================================

*

*     .. Intrinsic Functions ..

      INTRINSIC          LOG10, SQRT

*     ..

*     .. Executable Statements ..

*

*     If it looks like we're on a Cray, take the square root of

*     SMALL and LARGE to avoid overflow and underflow problems.

*

      IF( LOG10( LARGE ).GT.2000.D0 ) THEN

         SMALL = SQRT( SMALL )

         LARGE = SQRT( LARGE )

      END IF

*

      RETURN

*

*     End of DLABAD

*

      END