Dear Forum,
Arie Molina Rueda wrote:
My Situation:
------------
Im working in a problem involving in calculating _A LOT_ of tables of
marks, my problem is that GAP keeps stoping, telling me that my memory
assingned to GAP ran down.
The algorithm giving me trouble is very simple:
For every SimpleGroup(i,j){
-> Calculate ToM
-> A := Uncompress ToM
-> dim := Calculate Dimension of A
-> Save dim,i and j to file,
}
I assume GAP is keeping in memory those big arrays and thus running out
of memory.
My Question:
-----------.
Is there a way to free memory in GAP? or
to avoid GAP keeping those big things in memory?
Alas the above pseudo code does not provide enough information for
deciding what happens. In an off-list mail, Thomas Breuer asked the
following questions:
1. Do you write down a `for' loop over a list of groups or a list of
indices?
In the first case, the tables of marks are stored in the groups as
they are computed;
one remedy would then be to use `AttributeValueNotSet' instead of
calling `TableOfMarks' for the groups in question,
see the GAP Reference Manual for details about `AttributeValueNotSet'.
2. Do you compute the tables of marks from given group objects,
or do you use the library of tables of marks?
In the latter case, a certain number of data files are kept in memory;
one can reduce this number if required.
(Note that loading a table of marks from the library is much faster than
computing the table of marks anew, see `The Library of Tables of Marks'
in the GAP Reference Manual.)
3. Do I understand you right that you are interested only in the number
of conjugacy classes of subgroups of a given (simple) group?
If yes then you can completely avoid computing the table of marks,
and compute just `Length( ConjugacyClassesSubgroups( G ) )'.
Best wishes,
Stefan Kohl
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