NAME

       PDLABAD  -  take  as  input the values computed by PDLAMCH for underflow and overflow, and
       returns the square root of each of these values if the log of LARGE is sufficiently large

SYNOPSIS

       SUBROUTINE PDLABAD( ICTXT, SMALL, LARGE )

           INTEGER         ICTXT

           DOUBLE          PRECISION LARGE, SMALL

PURPOSE

       PDLABAD takes as input the values computed by PDLAMCH  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 PDLAMCH.  This subroutine is needed because PDLAMCH does  not  compensate  for
       poor arithmetic in the upper half of the exponent range, as is found on a Cray.

       In  addition,  this  routine  performs  a  global minimization and maximi- zation on these
       values, to support heterogeneous computing networks.

ARGUMENTS

       ICTXT   (global input) INTEGER
               The BLACS context handle in which the computation takes place.

       SMALL   (local input/local output) DOUBLE PRECISION
               On  entry,  the  underflow  threshold  as  computed  by  PDLAMCH.   On  exit,   if
               LOG10(LARGE) is sufficiently large, the square root of SMALL, otherwise unchanged.

       LARGE   (local input/local output) DOUBLE PRECISION
               On entry, the overflow threshold as computed by PDLAMCH.  On exit, if LOG10(LARGE)
               is sufficiently large, the square root of LARGE, otherwise unchanged.