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Using 'GAP with GRAPE' in SAGE notebook()?

asked 2011-12-09 10:21:44 +0200

GaryMak gravatar image

Hi I have been trying to do some graph computations using Leonard Soicher's GRAPE sub-package in GAP and have run across some problems in the notebook() version which do not occur in the command-line version (inside SAGE). Not sure if this is of interest to others, but here are the 2 things which are occurring so far (I have had confirmation from Leonard that he has never heard of these problems before, so they are not apparently to do with GRAPE itself): (1) - not so serious - every time a GRAPE routine is called it stores up a string "AgIcAgIcAgIc" and at the next 'print' command, spews out however many of these it has accumulated .... (2) - more serious - when we create graphs as objects in GRAPE, they are usually stored with a property autGroup which should be a Group(...) object from GAP. However strangely in this notebook() version we obtain (sometimes ...) a display saying "autGroup:=1", yet "1" is not a valid group description in GAP. In other words, something fishy's going on in the interpretation ...

Thanks for any help!

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answered 2011-12-10 14:24:12 +0200

GaryMak gravatar image

I think I can answer number (2) now myself ... it only occurs if I ask for the StructureDescription of the automorphism group, and then I ask it to output the graph (eg by typing gap> graphname;), but NOT using the "Print()" command. So in invoking the StructureDescription I seem to be switching the field of "autGroup" inside the GRAPE structure of a graph, to equal its StructureDescription instead; however only in one particular slicing of the data. BY THE WAY this DOES occur for normal command-line gap_console() inside SAGE - ie you do not need the notebook as I previously thought.

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Asked: 2011-12-09 10:21:44 +0200

Seen: 399 times

Last updated: Dec 10 '11