NAME

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

SYNOPSIS

       SUBROUTINE PSLABAD( ICTXT, SMALL, LARGE )

           INTEGER         ICTXT

           REAL            LARGE, SMALL

PURPOSE

       PSLABAD takes as input the values computed by PSLAMCH  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 PSLAMCH.  This subroutine is needed because PSLAMCH 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) REAL
               On  entry,  the  underflow  threshold  as  computed  by  PSLAMCH.   On  exit,   if
               LOG10(LARGE) is sufficiently large, the square root of SMALL, otherwise unchanged.

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