Re: Issue 3694 in sympy: Better Simplification of Gammas

2013-03-14 Thread sympy
Comment #4 on issue 3694 by smi...@gmail.com: Better Simplification of Gammas http://code.google.com/p/sympy/issues/detail?id=3694 Not as nice as I'd hoped...this is similar to the TR* routines of Fu...making sure the expression is in the form that will lead to simplification is tricky.

Re: Issue 3628 in sympy: trigsimp introduces extra factor

2013-03-14 Thread sympy
Updates: Status: Fixed Comment #3 on issue 3628 by smi...@gmail.com: trigsimp introduces extra factor http://code.google.com/p/sympy/issues/detail?id=3628 (No comment was entered for this change.) -- You received this message because this project is configured to send all issue

Re: Issue 3689 in sympy: Remove DeferredVector

2013-03-14 Thread sympy
Comment #2 on issue 3689 by smi...@gmail.com: Remove DeferredVector http://code.google.com/p/sympy/issues/detail?id=3689 The docstring shows an example. A vector whose components are deferred (e.g. for use with lambdify) Examples from sympy import DeferredVector,

Re: Issue 3692 in sympy: (Symbol(n,integer=True,even=True)/2).is_integer = False !

2013-03-14 Thread sympy
Comment #2 on issue 3692 by skirpic...@gmail.com: (Symbol(n,integer=True,even=True)/2).is_integer = False ! http://code.google.com/p/sympy/issues/detail?id=3692 https://github.com/sympy/sympy/pull/1896 -- You received this message because this project is configured to send all issue

Re: Issue 3694 in sympy: Better Simplification of Gammas

2013-03-14 Thread sympy
Comment #5 on issue 3694 by smi...@gmail.com: Better Simplification of Gammas http://code.google.com/p/sympy/issues/detail?id=3694 OK, nice again: e = (-gamma(k)*gamma(k + 2) + gamma(k + 1)**2)/gamma(k)**2 assert combsimp(e) == k**2 assert combsimp(1/e) == 1/k**2 e =

Re: Issue 3693 in sympy: solve() returns only subset of solutions for polynomial eqs

2013-03-14 Thread sympy
Comment #3 on issue 3693 by skirpic...@gmail.com: solve() returns only subset of solutions for polynomial eqs http://code.google.com/p/sympy/issues/detail?id=3693 This seems to be fixed.. Close? -- You received this message because this project is configured to send all issue

Re: Issue 3689 in sympy: Remove DeferredVector

2013-03-14 Thread sympy
Comment #3 on issue 3689 by asmeu...@gmail.com: Remove DeferredVector http://code.google.com/p/sympy/issues/detail?id=3689 Another example usage: https://github.com/sympy/sympy/blob/master/sympy/external/tests/test_numpy.py#L244. -- You received this message because this project is

Re: Issue 3287 in sympy: Merge DeferredVector and MatrixSymbol

2013-03-14 Thread sympy
Issue 3287: Merge DeferredVector and MatrixSymbol http://code.google.com/p/sympy/issues/detail?id=3287 This issue is now blocking issue sympy:3689. See http://code.google.com/p/sympy/issues/detail?id=3689 -- You received this message because you are listed in the owner or CC fields of this

Re: Issue 3689 in sympy: Remove DeferredVector

2013-03-14 Thread sympy
Updates: Blockedon: sympy:3287 Comment #4 on issue 3689 by asmeu...@gmail.com: Remove DeferredVector http://code.google.com/p/sympy/issues/detail?id=3689 Issue 3287 and issue 1268 are related. In fact, this might just be considered a duplicate of issue 3287. -- You received this

Re: [sympy] substitutions with unicode

2013-03-14 Thread Aaron Meurer
On Wed, Mar 13, 2013 at 8:58 PM, Duane Nykamp dqnyk...@comcast.net wrote: I see. Explicitly doing substitutions of the form (Symbol('oldvar'), Symbol('newvar')) makes sense. However, there unicode becomes a problem. Trying to use Symbol(varname) raises a AssertionError: type 'unicode'

Re: [sympy] Re: solve is terribly slow compared to sage

2013-03-14 Thread Ondřej Čertík
On Thu, Mar 14, 2013 at 12:34 AM, Aaron Meurer asmeu...@gmail.com wrote: This validates what I've often said, which is that if you use the right algorithms and the right data structures, then Python can be just as fast as a compiled alternative (especially since the right data structures

Re: [sympy] Re: Vector Calculus module

2013-03-14 Thread someone
Why not a middle ground? For some things it would be silly not to support n dimensions, like dot product, but for others, like cross product, the n-dimensional generalization is more complicated, and (if I understand correctly), not even technically a vector. For those cases, you could give

[sympy] Implementation of derivative and integral steps in Gamma

2013-03-14 Thread David Li
Hello all, I have implemented a module giving steps for most derivatives and some integrals for SymPy Gamma. However, it was suggested that at least some of this functionality should be added to SymPy itself. If so, what functionality should be added and how should it be integrated into SymPy?

[sympy] Re: Vector Calculus module

2013-03-14 Thread Prasoon Shukla
Why not a middle ground? Indeed. I like this idea a lot. +1 I think that Raoul's post takes care of the requirement of the list. Also, I will still take some time to write the proposal on the wiki. First, I want to be really clear on exactly what to implement and, more importantly, how to

Re: [sympy] Implementation of derivative and integral steps in Gamma

2013-03-14 Thread Stefan Krastanov
This seems very nice. Have you looked at the rewrite rules and strategies modules that are currently developed and talked about on the mailing list? Given that you follow the same paradigm I guess this would be the correct path to merge your work. I am a bit worried that you might have

Re: [sympy] Implementation of derivative and integral steps in Gamma

2013-03-14 Thread Ronan Lamy
Le 14/03/2013 15:22, David Li a écrit : The code makes use of context managers, which would need to be replaced in order to maintain Python 2.5 compatibility. That's not a problem, you can use 'from __future__ import with_block'. OTOH, .format() is 2.7+ only, so it is a compatibility

Re: [sympy] Re: solve is terribly slow compared to sage

2013-03-14 Thread Ronan Lamy
Le 14/03/2013 09:42, Ondřej Čertík a écrit : Mateusz and I discussed this last few days (I visited him in Wroclaw) and I think we both agreed that a good idea is for me (or others) to finish the experimental C++ core (https://github.com/certik/csympy) so that we can run some benchmarks and play

[sympy] Re: Implementation of derivative and integral steps in Gamma

2013-03-14 Thread David Li
Alright, thank you all for the feedback! I just started looking at the strategies module, I think I could map my rules to rules in the strategies module and have intsteps/diffsteps be a strategy; I'll look into this some more. I can get rid of the format function easily, I'm not really using

Re: [sympy] Re: Implementation of derivative and integral steps in Gamma

2013-03-14 Thread Matthew Rocklin
The driving idea behind strategies is that you should make lots of little functions that each do one thing. These should separately be composed together to make larger functions. This way the little mathematical transformations can be reused in the future or can be wrapped with the kind of

Re: [sympy] Re: Implementation of derivative and integral steps in Gamma

2013-03-14 Thread Stefan Krastanov
Slightly off topic: I think that many people would be interested to see a blog post on planet.sympy.org about this development. On one hand you have done a lot of work on gamma itself, on the other your work with this integrator shows a nice way to extend sympy without worrying too much about

Re: [sympy] Re: solve is terribly slow compared to sage

2013-03-14 Thread Ronan Lamy
Le 14/03/2013 20:16, Ondřej Čertík a écrit : On Thu, Mar 14, 2013 at 7:50 PM, Ronan Lamy ronan.l...@gmail.com wrote: Le 14/03/2013 09:42, Ondřej Čertík a écrit : In general, I think it's quite amazing how fast Python actually is, that sympy can compete very well with for example Maxima, if

Re: [sympy] Re: solve is terribly slow compared to sage

2013-03-14 Thread Aaron Meurer
On Thu, Mar 14, 2013 at 3:42 AM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Thu, Mar 14, 2013 at 12:34 AM, Aaron Meurer asmeu...@gmail.com wrote: This validates what I've often said, which is that if you use the right algorithms and the right data structures, then Python can be just as

Re: [sympy] Re: solve is terribly slow compared to sage

2013-03-14 Thread Matthew Rocklin
I support the idea of being smarter about running fewer Python functions. Your post brought up a couple experiences I had trying to get unification based rewriterules to run efficiently. - expand currently works by recursively calling _eval_expand_hint on an expression. So if you have

Re: [sympy] testing for structural equality is easy with unify

2013-03-14 Thread Matthew Rocklin
Normal unification is decently fast. A simple implementation in another project is herehttps://github.com/logpy/logpy/blob/master/logpy/core.py#L58. However our implementation of unification in an associative/commutative context is naive and painfully slow. AC matching is a hard problem but in

Re: [sympy] GSoC Proposal : Automating the release process of sympy

2013-03-14 Thread Ramana Venkata
@aaron I have sorted out the issues into Sympy-Bot and Reviews.sympy.org Bot: 144 142 139 121 120 108 95 94 89 80 73 63 62 56 21 2 Review.sympy.org: 138 132 120 119 117 103 102 90 59 57 55 51 50 49 48 47 46 45 42 35 16 Are the issues 57, 48 still valid? On Wed, Mar 13, 2013 at 8:26 PM,

Re: [sympy] testing for structural equality is easy with unify

2013-03-14 Thread Chris Smith
On Fri, Mar 15, 2013 at 6:56 AM, Aaron Meurer asmeu...@gmail.com wrote: How fast is this? Does it scale well for large expressions with many variables? Can it be modified to return the mapping? My symatch branch does what your asking...it's called `symbol_match` as I recall. I'm stalled

Re: [sympy] SymPy at SciPy2013

2013-03-14 Thread Aaron Meurer
I'd love to see a SymPy presence at the conference, even if it's just attendees. This year, sponsorships are open to everyone, not just students: http://conference.scipy.org/scipy2013/reg_fin_aid.php. Aaron Meurer On Wed, Mar 13, 2013 at 1:43 PM, Matthew Rocklin mrock...@gmail.com wrote: The

Re: [sympy] GSoC Proposal - ODE Solver using Lie Groups

2013-03-14 Thread Manoj Kumar
I'd just like to clarify if my post was a bit ambiguous. I would like to implement both of these in a single project 1. Adding lie groups support for first order ODE's 2. Series solutions to first and second order ODE's I would like to know if it would be good. -- Regards, Manoj Kumar, Mech

Re: [sympy] Re: solve is terribly slow compared to sage

2013-03-14 Thread Chris Smith
On Fri, Mar 15, 2013 at 6:24 AM, Aaron Meurer asmeu...@gmail.com wrote: On Thu, Mar 14, 2013 at 3:42 AM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Thu, Mar 14, 2013 at 12:34 AM, Aaron Meurer asmeu...@gmail.com wrote: This validates what I've often said, which is that if you use the