Dear Lee Martin, [I suggest that further discussion on these issues is not sent to the forum@, mail address, which copies to hundreds of subscribers, but to support@]
> How to edit the value of dictionary? > How to append a function to a list which is a value of dictionary? The values of a dictionary are immutable and cannot be changed (cleanly), so this is not possible. Concerning the memory problems you reported, did you by any chance get the error message: exceeded the permitted memory (`-o' command line option) If so, you can find a description under http://mail.gap-system.org/pipermail/forum/2010/002986.html Regards, Alexander Hulpke > > Regards, > > Martin > > > Subject: Re: [GAP Forum] which function of dictionary can use polynomial or > > function as key > > From: hul...@math.colostate.edu > > Date: Wed, 24 Sep 2014 09:27:04 -0600 > > CC: fo...@gap-system.org > > To: tesl...@hotmail.com > > > > Dear Forum, > > > > On Sep 24, 2014, at 9/24/14 3:21, Lee Martin CCNP <tesl...@hotmail.com> > > wrote: > > > > > would like to use rational function as key in dictionary like table > > > function in maple > > > which function is a dictionary can use function as key and value as list > > > to store ideals. > > > > Lookup dictionaries currently work with rational functions, e.g: > > > > gap> > > R:=PolynomialRing(Rationals,["x","y","z"]);AssignGeneratorVariables(R); > > Rationals[x,y,z] > > #I Assigned the global variables [ x, y, z ] > > > > gap> d:=NewDictionary(x,true); > > <object> > > gap> AddDictionary(d,x,1); > > gap> AddDictionary(d,y,2); > > gap> LookupDictionary(d,x); > > 1 > > gap> LookupDictionary(d,z); > > fail > > gap> AddDictionary(d,x/y,2); > > gap> LookupDictionary(d,z); > > fail > > gap> LookupDictionary(d,x/y); > > 2 > > > > Instead of numbers you should be able to store arbitrary associated > > information. However internally lists will be made immutable, so if your > > ideal list is expected to grow you would need to keep a separate (mutable) > > list of the ideal lists, storing only an index in the dictionary. > > > > I note that > > > > gap> RepresentationsOfObject(d); > > [ "IsComponentObjectRep", "IsDictionaryDefaultRep", "IsListDictionary", > > "IsListLookupDictionary", "IsSortDictionary", "IsSortLookupDictionary" ] > > > > this currently uses sorted lists internally and not yet hashing. To enable > > hashing, one would have to add a method for SparseHashKey for rational > > functions, which currently is not on the list of features. > > > > Best, > > > > Alexander Hulpke > > > > > > > Regards, > > > Martin > > > _______________________________________________ > > > Forum mailing list > > > Forum@mail.gap-system.org > > > http://mail.gap-system.org/mailman/listinfo/forum > > _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
