[ut.na] NAgMAg Vol 89 #06

krj@na.toronto.edu (Ken Jackson) (03/24/89)

From:	nagmag%ukc.ac.uk@NSS.Cs.Ucl.AC.UK
Date:	Thu, 23 Mar 89 10:25:39 EST
Subject: NAgMAg Vol 89 #06
Sender: trh%ukc.ac.uk@NSS.Cs.Ucl.AC.UK

NAgMAg		Thursday,  March 23 1989	Volume 89   Issue 6

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%%   The official electronic digest of the NAG Users Association   %%
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Today's Topics
                                 E01ADF
                  Assistance sought for Mark 3 Graphics
                           Replies to NAGMAG 5
                               C Software
%% Editorial
%%
%% This digest is going out a day early -- so it can sit in your
%% mailbox 'til you've recovered from gorging too many chocolate eggs!
%% I'm away next week so the next digest (if there's any input -- HINT)
%% will go out sometime during the week beginning April 3.
%%
%% NAG wish it to be known that this is NOT an official NAG digest but
%% it IS an official NAGUA digest -- hence the appearance of the
%% boxed comment in the header.
%%
%% As you will see I have been forced to insert my own articles in
%% an attempt to generate some discussion. I don't have an infinite
%% supply of these. I just don't believe nobody has anything to say
%% about NAG. One or two people have said they are only interested
%% in particular areas (e.g., statistics) -- don't be afraid of
%% submitting articles I'm sure other readers will be interested.
%%
%% Have a peaceful Easter.
%%                         Tim

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Date: Fri,17 Mar 89 16:37:36 GMT
From: Bob_Hatfield@vme.ccc.nottingham.ac.uk
Subject: E01ADF

 I have a copy of the documentation for E01ADF if you still haven't
found a copy.
 
   Bob Hatfield
  Cripps Computing Centre
  University of Nottingham

---------------------------

Date:		Sun, 19 MAR 89 17:28:50 GMT
From:		DAVID@vax.nag.co.uk
Subject: Assistance sought for Mark 3 Graphics


Requests for assistance from NAG Graphics Users
-----------------------------------------------

1)Do any of our NAG Graphics users have any data cases and/or 
programs which generate interesting pictures or illustrate 
applications to which NAG Graphics has been put? 

We would like to include examples of 'real usage' of our software in
such documentation as advertising material, newsletter articles,
displayed on our trade stand, used to illustrate talks about the NAG 
Graphics etc.

We would welcome any contributions of: code (and data), data only 
or pictoral output (e.g. 35mm slide, good quality hardcopy etc.), 
preferably accompanied by a brief explanatory description. 

The source of any contributions would of course be acknowledged if 
we were to use them.


2) In the Mark 3 Graphics Library Manual we wish to include a 
section describing common user mis-understandings and the corrective 
action to take. Below please find a list which NAG have compiled. We 
believe that many NAGUA members will perhaps have experienced other
problems which should be included. If so please let us know and we 
will see that they appear in the list.

Corrective actions for commonly encountered errors.
--------------------------------------------------

The following Section has been derived directly as a result of questions
received from our user sites about problems encountered when running the
 
NAG Graphics Library. It is hoped that the following table will 
assist you in identifying the cause of any problems you may 
encounter when linking or running NAG Graphics. 

To use this table you should first identify the category of your problem
(left hand side of table) and check each of the possible causes listed
(right hand side) in turn. Full details associated with each cause are 
listed following the table (indexed alphabetically).

Should you still be unable to resolve your problem after having checked
the advice given, you are recommeneded to contact your local NAG site 
representative for further assistance. 


         Problem                                    Possible Cause
         -------                                    --------------

Problems encountered at Link time:

   Messages are generated indicating      Libraries being searched in 
   that there are unresolved external     wrong order (a)
   references (or multiple references)
                                          Incorrect routine name used (b)


Problems encountered at Run time:

   Program will not run without           Incorrect Parameter(s) 
   generating run time messages           supplied (c) 
   e.g. access violations.                Wrong base precision used (d)

                                          Program was copied from
                                          Handbook (e)

                                          Wrong compiler version (f)


   Graphical output is incomplete         NAG Graphics has not been 
                                          terminated correctly (g)


   Graphical output generated was         Wrong base precision used (d)
   not what was expected
                                          Wrong NAG Graphics routine
                                          used (h)

                                          Incorrect Parameter(s)
                                          supplied (c) 

                                          Site specific modifications
                                          made to NAG Graphical 
                                          Interface (j)


   Example output plot differs from       Incorrect Parameter(s) 
   that printed in the Handbook           supplied (c) 
 
                                          Underlying plotting software
                                          has 

                                          different attributes from one 
                                          used
                                          by Handbook (Adobe PostScript)
                                          (i)
 
                                          Site specific modifications
                                          made 

                                          to NAG Graphical Interface (j)

                                          
Possible causes - further guidance 
----------------------------------

 a) Libraries are being searched in wrong order
    The correct order for linking NAG graphics routines is:

     NAG Graphics, NAG Graphical Interface, NAG routines,
     Plotting Software

    Please check the instructions supplied by your site or contact your
    site representative for further assistance.

 b) Incorrect routine name used
    Check that you have used the NAG naming convention applicable to
    your site. NAG graphics routine names may end in either F 
    (e.g J06GAF) or E (e.g. J06GAE).

    Check that you have not mistyped the NAG Graphics routine name. All 
    NAG Graphics routines start with the characters J06 (J-zero-6) not 
    JO6 (J-oh-6); it is easy to mistype this. 

    Please see section 2 of Background Notes for further details.

 c) Incorrect Parameter(s) supplied 
    Check that you have not supplied an incorrect value for one of 
    the input parameters to your selected NAG Graphics routine; you 
    are advised to check the following:

      - Your calling sequence(s) matches that given in the associated 
        routine documention.
      - The type of each variable
      - That all EXTERNAL subroutines have been declared
      - The base precision being used for interpreting real variables
      - That you have supplied sufficient workspace
      - The dimension of arrays   
      - The order of dimensions for 2D arrays

 d) Wrong base precision used 
    NAG Graphics routines are available in both single and double
    precisions. It is normal for a site to make available only one 
    precision version of the Library. If you call NAG Graphics 
    with single precision arguments and the implementation available
    at your site is double precision your program may behave
    unpredictably. A program will not necessary fail
    and a plot may even be generated.
   
    A common cause for selecting the wrong precision is copying code or
    routine parameter specifications directly from the User Handbook
    without considering the precision of the NAG Graphics Library you 
    are using. The examples and text in the NAG Graphics Library
    Handbook are printed to reflect single precision implementations. 
    Emboldened terms are used to reflect those elements which need to
    be converted to double precision 

    Please see section 2 of Background Notes for further details.

 e) Program was copied from Handbook 
    Typing errors may be the source of your problem. 

    You are advised that your site has a copy of all example programs
    printed in the Handbook which are specific to your local
    implementation of the NAG Graphics Library. 

    Please contact your site representative for further details.

 f) Wrong compiler version selected
    When linking to NAG Graphics Libraries on some systems, especially 
    Personal computers you should ensure that your compiler is    
    compatible with the implementation NAG have supplied. The following
    should be checked:
       - Compiler version
       - Whether a co-processor is required or not (PC machines)
       - Whether G-Floating or D-Floating arithmetic is being used
 
    You can determine the compiler version of the NAG Graphics
    Implementation available at your site by calling NAG Graphics 
    routine J00AAF (zero-zero).

    Please contact your site representative for further assistance.

 g) NAG Graphics has not been terminated correctly
    You have omitted to call NAG Graphical Interface routine J06WZF.
    J06WZF ensures that the underlying plotting software and NAG 
    Graphics are terminated correctly and that all graphical
    buffers are flushed.

 h) Wrong NAG Graphics routine selected 
    Check that you have selected the appropriate routine to produce
    your desired output plot. 

    A Pictoral Guide to using the NAG Graphics Library and detailed
    guidance in each Chapter Introduction have been provided in the 
    Handbook to assist you in your selection of routines.

 i) Underlying Plotting Software attributes vary
    The form of graphical output is very much dependent upon your target
    device and the NAG Graphical Interface in use. You are recommended
    to use discretion when judging the acceptability of graphical 
    results. The graphical plots printed in the User Handbook are
    supplied as examples of the style of output you would expect from 
    the routine.

    The general form of output generated should match that supplied
    i.e. the position of lines, textual content, relationship of
    plot to the viewport etc. should be in a similar position, 
    however differences such as the 
    following can be expected:

     - Representations of line styles (other than solid) 
     - Marker styles
     - Text font representation.
     - Text sizes (particularly if using medium quality (hardware) text.
     - Colours (of lines or filled areas)
     - Package supplied fill styles (most example programs supplied use 
       NAG generated fill styles; these should not vary significantly) 

 j) Site specific modifications
    Your site may have made modifications to the default settings of the
    NAG Graphical Interface you are using. Any modifications made should
    be indicated in local documentation.

    Please contact your site representative for further details.
    
LAC/16-Mar-1989


---------------------------

Date:		Sun, 19 MAR 89 18:08:01 GMT
From:		DAVID@vax.nag.co.uk
Subject: Replies to NAGMAG 5

RE: E01ADF

NAG keeps copies of the withdrawn routine documentation for these
purposes. In brief:
   SUBROUTINE E01ADF(N,A,X,Y,W,D,IG,VAL)
   INTEGER N,IG
   real A,X(IG),Y(IG),W(IG),D(IG),VAL

N- the number of intervals ie there are N+1 datapoints
X,Y the datapoints (x,y)
W,D work arrays
A   specified point where interpolated value is required
VAL on exit contains the answer.

Exactly the same answers should not be expected. In the newer 
routines more natural end conditions were imposed ; earlier software
would not reproduce a cubic exactly - a feature that still exists
in other libraries I believe.

RE: GAMS

Ron Boisverts offer is very atractive to NAG. We would hope that
MARK 14 would be included. For completeness the Sparse Matrix
Library, the NAG Graphics, and the statistical packages GENSTAT and
GLIM should be seen alongside the other entries. 

We would like to take the latest version when it becomes available
and make these additions.

---------------------------

Date: Thu, 23 MAR 89 15:15:01 GMT
From: trh@ukc.ac.uk
Subject: C software

I was recently assaulted by a colleague waving an advertisement
for NAG software which claimed to be able supply numerical s/ware
in Fortran/Pascal/ADA and C.  What exactly is available in C?
Are there any plans to produce a C version of the main subroutine
library? If not, why not?

Anybody else out there perceive a need for C numerical s/ware?

Tim

---------------------------


%%
%%   Replies or submissions to          nagmag@uk.ac.ukc
%%   Distribution changes to    nagmag-request@uk.ac.ukc
%%
%%   END OF ISSUE 

Reposted by
-- 
Kenneth R. Jackson,            krj@na.toronto.edu   (on Internet, CSNet, 
Computer Science Dept.,                              ARPAnet, BITNET)
University of Toronto,         krj@na.utoronto.ca   (CDNnet and other 
Toronto, Canada  M5S 1A4                             X.400 nets (Europe))
(Phone: 416-978-7075)          ...!{uunet,pyramid,watmath,ubc-cs}!utai!krj