Here's what we have been doing for 7th week of GSoC.
Kalevi mentioned about the $LaTex$ not getting rendered on Planet Sympy website, thought it works fine on my website. Following the conversation Aaron opened issue planet-sympy/issues/45, though it hasn't been fixed.
What do we do this week?Implemented the Reidemeister Schreier algorithm (shortly RS algorithm) and Titze Transformations (shortly TT) in PR #11295 . Most of the pseudo code for RS algorithm is there in the Handbook , perhaps majority of the time was spent working with TT. There isn't any pseudo code available for making that work, but we gathered detailed information from  combined with Havas Paper . What issues were there? In the both  and , there a few assumptions made, like
> shall assume that all relators are always cyclically reduced; that is, that whenever a relator is changed, it is immediately replaced by its cyclic reduction.
I opened the issue #11352 regarding a typo I left in
coset_enumeration_c. Though I didn't expect a PR, @kritkaran94 fixed it. Perhaps a good test case which makes use of different value of
max_stack_size was suggested by Kalevi. One thing came back to me, "everthing is an object in Python", the fact that initially
CosetTableDefaultMaxLimit was a module level variable initially and we changed it to
CosetTable.CosetTableDefaultMaxLimit, module is an object so is a
What hasn't been done?
- No testing for a few of techniques, for example currently no tests exist for
elimination_technique_2, which is a variant of the elimination procedures.
- TT doesn't produce the best possible result.
Though doing this seemed easy at first. But I didn't wanted to apply
identity_cyclic_reduction every change as there can be a few instance where it not necessary to do this, perhaps because of the property of words.
The good thing about this week was that I could now understand the limitations that will remain after my GSoC project. The scope of Computational Group Theory is more than what I expected. Apart from that I will be leaving for my college this week stars from 15th of July, perhaps I don't know how things will shift regarding time for GSoC. Let's be realistic :)
- 1. Derek F. Holt, Bettina Eick, Bettina, Eamonn A. O'Brien, "Handbook of computational group theory", Discrete Mathematics and its Applications (Boca Raton). Chapman & Hall/CRC, Boca Raton, FL, 2005. ISBN 1-5848-372-3 .
- 2. George Havas, "Reidemeister-Schreier program"