On Tue, Mar 11, 2014 at 4:01 PM, Anurag Sharma <[email protected]> wrote: > Hi Aaron and everyone > Now that a mandatory patch for the application is in, I can discuss in > details regarding the application which I wish to propose. > This is gonna be a series of short posts where I can discuss individual > elements which I can/should include or what may not be necessary. > These are the first set of changes I wish to implement: > > 1. I have started on Chetna's branch and have dealt with the issue of not > hardcoding 'a' > Reference : https://github.com/sympy/sympy/pull/2380 > What I have seen by going through the code that at some places she has > diverged from keeping the variables same as in the book. I have taken the > liberty to change the variable names and > keep the implementation as close to the book as possible. Is it okay to do > that ? Since the code is not merged I guess it wont hurt to change names and > do the modifications.
Yes, please do that. > Also she was passing 'a' in all the functions but using the default value > '-1' inside. When I replace that with 'a' I find that a doesn't always carry > '-1' value. Rather in a recursive call its values changes to '+1' at some > instances because she is using the same variable inside the loop too. > > 2. In rde.py and prde.py I want to merge special_denom in one file, as they > are very similar. If you can keep the code readable, OK. > > 3. To recognize whether a rational function is derivative of a rational > function we right now use Laurent Series method and then hermite reduction > if the first one fails. > I think we can/should also Marik's Criteria as Chetna had suggested and as > this mathstackexchange answer tells us : > http://math.stackexchange.com/questions/418482/primitive-of-a-rational-function > This will save us from using "costly" hermite reduction in more cases. And > implementation shouldn't be tough as we already have subroutines required > for the algorithm. > What does the community say about it ? Sounds good. > > Cheers > Anurag > > P.S Aaron I deleted the merge_cds branch after the changes were merged > yesterday from my github repo. I still have that branch on my system because > that is the only branch which has cds.py and rde.py etc in the latest > version (chetna's version) In case I want you to show my hack for [1] Should > i send a new PR from this branch. This PR wont get merged before the > deadline but will serve as a mark on my progress on chetna's work. Yes. Aaron Meurer > > > > > > On Wednesday, January 22, 2014 8:00:08 PM UTC+5:30, Anurag Sharma wrote: >> >> Hello everyone. >> >> This post is regarding the gsoc idea of implementing (or continuing ) the >> work of Aaron Meurer and Chetna Gupta on implementation of Risch Algorithm >> for symbolic integrations. I have gone through the PR mentioned on the ideas >> page. It seems there has been good progress last summer. >> I have fairly decent background in abstract algebra and universal algebra. >> Though I haven't formally done anything related to Differential Algebra. >> >> I wished to know the following things: >> >> 1. There are 3 remaining tasks mentioned in the PR. Would it be okay to >> start on one of them ? (Most probably the one which asks to not hard code >> the value of 'a' ) >> >> 2. Has there been any progress other than that mentioned in that PR? >> >> 3. I have skimmed through the first chapter of Bronstein's book. Algebraic >> Preliminaries. Nothing new there. But the second chapter introduces >> algorithms which I have never implemented and some of them I had not even >> heard of. I would be really glad if you could tell me what sort of >> mathematical background is required to contribute efficiently to this part >> of the project. >> >> I would be really glad if you could link me to some literature on net >> which explains the Risch algorithm and implementation issues. In the >> meanwhile I'll try to procure the mentioned text from my college library. >> >> Apart from Aaron Meurer and Chetna Gupta who else has worked on this part >> ? It would be really nice if I knew more people familiar to this part of >> sympy so that I wont have to bug Aaron with every little issue :).. I have >> tried contacting Chetna but I guess she is not much active now. >> >> Cheers >> Anurag >> >> > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/46cf5047-fe58-40b5-931a-d8360c1ecccc%40googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6%2B-g6gbv25KhETvG-mDQsj%3Dur_1Kzko-HHUofGLaT%3D5iw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
