debian man page for pdlabad

PDLABAD(l)					      LAPACK auxiliary routine (version 1.5)						PDLABAD(l)

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.

LAPACK version 1.5						    12 May 1997 							PDLABAD(l)