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.

SMALL

          SMALL is 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

          LARGE is 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.

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NAG Ltd.

December 2016