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+      SUBROUTINE DLABAD( SMALL, LARGE )
+*
+*  -- LAPACK auxiliary routine (version 3.1) --
+*     Univ. of Tennessee, Univ. of California Berkeley 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