From GOLUB@SU-SCORE.ARPA Wed Oct 16 22:05:26 1985
Received: from SU-SCORE.ARPA (su-score.arpa.ARPA) by anl-mcs.ARPA ; Wed, 16 Oct 85 22:05:03 cdt
Return-Path: <rhbartels%watcgl%waterloo.csnet@CSNET-RELAY.ARPA>
Received: from CSNET-RELAY.ARPA by SU-SCORE.ARPA with TCP; Wed 16 Oct 85 13:53:44-PDT
Received: from waterloo by csnet-relay.csnet id al25408; 16 Oct 85 16:50 EDT
Date: Wed, 16 Oct 85 12:48:58 edt
From: Richard Bartels <rhbartels%watcgl%waterloo.csnet@CSNET-RELAY.ARPA>
Message-Id: <8510161648.AA02190@watcgl.UUCP>
To: na.dis@su-score.ARPA
Subject: UNIX/f77 dpmpar
Resent-Date: Wed 16 Oct 85 18:48:26-PDT
Resent-From: Gene Golub (415/497-3124) <GOLUB@SU-SCORE.ARPA>
Resent-To: :;
Resent-Message-Id: <12151704861.14.GOLUB@SU-SCORE.ARPA>
Status: RO


The following is a version of the MINPACK routine DPMPAR,
which provides double-precision machine constants, suitable
for use with UNIX/f77.  This is being circulated because it
was discovered that nobody here at Waterloo knew how to specify
these constants -- including Esmond Ng (and that is pretty shocking).

This version of DPMPAR checks out correctly with the MINPACK machine-constant
verifier run under UNIX/f77.

Bug fixes, comments, and improvements solicited.

------------------  cut here ---------------------------------------
      DOUBLE PRECISION FUNCTION DPMPAR(I)
      INTEGER I
C     **********
C
C     FUNCTION DPMPAR
C
C     THIS FUNCTION PROVIDES DOUBLE PRECISION MACHINE PARAMETERS
C     WHEN THE APPROPRIATE SET OF DATA STATEMENTS IS ACTIVATED (BY
C     REMOVING THE C FROM COLUMN 1) AND ALL OTHER DATA STATEMENTS ARE
C     RENDERED INACTIVE. MOST OF THE PARAMETER VALUES WERE OBTAINED
C     FROM THE CORRESPONDING BELL LABORATORIES PORT LIBRARY FUNCTION.
C
C     THE FUNCTION STATEMENT IS
C
C       DOUBLE PRECISION FUNCTION DPMPAR(I)
C
C     WHERE
C
C       I IS AN INTEGER INPUT VARIABLE SET TO 1, 2, OR 3 WHICH
C         SELECTS THE DESIRED MACHINE PARAMETER. IF THE MACHINE HAS
C         T BASE B DIGITS AND ITS SMALLEST AND LARGEST EXPONENTS ARE
C         EMIN AND EMAX, RESPECTIVELY, THEN THESE PARAMETERS ARE
C
C         DPMPAR(1) = B**(1 - T), THE MACHINE PRECISION,
C
C         DPMPAR(2) = B**(EMIN - 1), THE SMALLEST MAGNITUDE,
C
C         DPMPAR(3) = B**EMAX*(1 - B**(-T)), THE LARGEST MAGNITUDE.
C
C     MINPACK. VERSION OF NOVEMBER 1979.
C     BURTON S. GARBOW, KENNETH E. HILLSTROM, JORGE J. MORE
C
C     UNIX/F77 VERSION OF OCTOBER 16, 1985
C     RICHARD BARTELS
C
C     **********
      DOUBLE PRECISION RMACH(3)
      INTEGER NMAX(2)
      EQUIVALENCE(NMAX(1),RMACH(3))
C
      DATA RMACH(1) /O'22200'/
      DATA RMACH(2) /O'200'/
      DATA NMAX(1) /O'37777677777'/
      DATA NMAX(2) /O'37777777777'/
C
      DPMPAR = RMACH(I)
      RETURN
C
C     LAST CARD OF FUNCTION DPMPAR.
C
      END



.