dlabad(3S)

NAME
     DLABAD - take 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

SYNOPSIS
     SUBROUTINE DLABAD( SMALL, LARGE )

         DOUBLE         PRECISION LARGE, SMALL

IMPLEMENTATION
     These routines are part of the SCSL Scientific Library and can be loaded
     using either the -lscs or the -lscs_mp option.  The -lscs_mp option
     directs the linker to use the multi-processor version of the library.

     When linking to SCSL with -lscs or -lscs_mp, the default integer size is
     4 bytes (32 bits). Another version of SCSL is available in which integers
     are 8 bytes (64 bits).  This version allows the user access to larger
     memory sizes and helps when porting legacy Cray codes.  It can be loaded
     by using the -lscs_i8 option or the -lscs_i8_mp option. A program may use
     only one of the two versions; 4-byte integer and 8-byte integer library
     calls cannot be mixed.

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.

SEE ALSO
     INTRO_LAPACK(3S), INTRO_SCSL(3S)

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