[GAP Forum] autoload packages

[Alexander Konovalov]

Dear Mathieu, dear Forum,

On 6 Jul 2012, at 14:26, Mathieu Dutour wrote:

> Has this changed with version 4.5?
> 
> For example for JohnsonGraph(8,4)
> I need to put a RequirePackage("grape") in order to get it,
> while I did not needed it for 4.4
> 
>  Mathieu

To my best knowledge, Grape was not autoloaded in GAP 4.4. Maybe
that installation was made using another installer, or used .gaprc 
file containing a call to load Grape? Also, 'RequirePackage' is 
an old name which was already replaced by 'LoadPackage' some time 
ago. Anyhow, with GAP 4.5 the concept of autloaded packages has been 
withdrawn. 

Please see '?The gap.ini and gaprc files' for the description
of the current mechanism for the user's customisation. If you 
don't have the gap.ini file yet, the easies way is to call
WriteGapIniFile and then to edit the file which will be created,
for example:

gap> WriteGapIniFile();
#I  File ......some-path/gap.ini successfully written.
true

Now open the file in the location told by the command above
and find there the lines:

##  A list of names of packages which should be loaded during startup. For
##  backwards compatibility, the default lists most of packages that were
##  autoloaded in GAP 4.4 (add or remove packages as you like).
# SetUserPreference( "PackagesToLoad", [ "autpgrp", "alnuth", "crisp", 
# "factint", "fga", "irredsol", "laguna", "polenta", "polycyclic", 
# "resclasses", "sophus" ] ); 

Now, if you wish Grape to be loaded automatically each time you start
GAP, all you need to do is to uncomment SetUserPreference call and add 
"grape" there.

Hope this helps,
Alexander