Dear all, Using DeclareAttribute and then the appropriate getters and setters for that attribute seems to be a good way to "memoize" a computation in GAP.
I often find myself trawling through the small-groups library. If I do something like DeclareAttribute( "Foo", IsGroup ); G:=SmallGroup(8,3); # pretend that some involved computation computes the value bar SetFoo(G,bar); then, for the rest of the session I can use HasFoo(G) and Foo(G) to avoid repeating my computation. However, the attribute Foo is associated to the object referenced by the identifier G. If I overwrite G, say I do G:=SmallGroup(8,3); again, then my stored attribute is lost. This makes sense. The result of IsAttributeStoringRep(SmallGroup(8,3)); is "true" but attempting to set my custom attribute for SmallGroup(8,3) directly seems to do nothing: it is not listed when I run KnownAttributesOfObject(SmallGroup(8,3)). What I would really like to do is set attributes for groups in the small groups library in such a way that this information persists between sessions. Is there any way to do this or any way to achieve something similar? I guess I could have a big hash-table storing the information I want, perhaps with small-group IDs as the keys, which I could read at the beginning of a session and write at the end, but I'm wondering if there is a more idiomatic way to do things. Thanks & best regards, Bob _______________________________________________ Forum mailing list Forum@gap-system.org https://mail.gap-system.org/mailman/listinfo/forum
