Previous: dhseqr Up: ../lapack-d.html Next: dlabrd

dlabad

 NAME
      DLABAD - take as input the values computed by SLAMCH 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

 PURPOSE
      DLABAD takes as input the values computed by SLAMCH 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.