DLAMC3  is intended to force  A  and  B  to be stored prior to doing


 the addition of  A  and  B ,  for use in situations where optimizers


 might hold one of these in a register.

LAPACK is a software package provided by Univ. of Tennessee, Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..

November 2011

A

          A is a DOUBLE PRECISION

B

          B is a DOUBLE PRECISION


          The values A and B.

 DLAMCH determines double precision machine parameters.

CMACH

          Specifies the value to be returned by DLAMCH:


          = 'E' or 'e',   DLAMCH := eps


          = 'S' or 's ,   DLAMCH := sfmin


          = 'B' or 'b',   DLAMCH := base


          = 'P' or 'p',   DLAMCH := eps*base


          = 'N' or 'n',   DLAMCH := t


          = 'R' or 'r',   DLAMCH := rnd


          = 'M' or 'm',   DLAMCH := emin


          = 'U' or 'u',   DLAMCH := rmin


          = 'L' or 'l',   DLAMCH := emax


          = 'O' or 'o',   DLAMCH := rmax


          where


          eps   = relative machine precision


          sfmin = safe minimum, such that 1/sfmin does not overflow


          base  = base of the machine


          prec  = eps*base


          t     = number of (base) digits in the mantissa


          rnd   = 1.0 when rounding occurs in addition, 0.0 otherwise


          emin  = minimum exponent before (gradual) underflow


          rmin  = underflow threshold - base**(emin-1)


          emax  = largest exponent before overflow


          rmax  = overflow threshold  - (base**emax)*(1-eps)

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

November 2011