dlamch(3S)

NAME
     DLAMCH - determine double precision machine parameters

SYNOPSIS
     DOUBLE PRECISION FUNCTION DLAMCH( CMACH )

         CHARACTER    CMACH

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
     DLAMCH determines double precision machine parameters.

ARGUMENTS
     CMACH   (input) CHARACTER*1
             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)
SEE ALSO
     INTRO_LAPACK(3S), INTRO_SCSL(3S)

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