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Speed improvements for ask() (sympy.queries.ask)

Category: General, sympy, Tecnologí­a

I managed to overcome the overhead in ask() that arises when converting between symbol and integer representation of sentences in conjunctive normal. The result went beyond what I expected. The test suite for the query module got 10x times faster in my laptop. From 26 seconds, it descended to an …

Logic module (sympy.logic): improving speed

Category: General, sympy, Tecnologí­a

Today I've been doing some speed improvements for the logic module. More precisely, I implemented an efficient internal representation for clauses in conjunctive normal form. In practice this means a huge performance boost for all problems that make use the function satisfiable() or dpll_satisfiable(). For example, test_dimacs.py has moved …

Refine module

Category: sympy, Tecnologí­a

This commit introduced a new module in sympy: the refine module. The purpose of this module is to simplify expressions when they are bound to assumptions. For example, if you know that x>0, then you can simplify abs(x) to x. This code was traditionally embedded into the core …

Query module - finally in trunk

Category: General, sympy, Tecnologí­a

The query module is finally in the main SymPy repository. I made substantial changes since last post, most of them at the user interface level (thanks to Vinzent and Mateusz for many insightful comments). Main function is ask(), which replaces the old expression.is_* syntax. You can ask many things …

django, change language settings dynamically

Category: General, Tecnologí­a

After some failed attempts, I just found how to change the language settings dynamically in django, and I thought it could be useful to someone. Just use function activate() from django.utils.translation. For example: [cc lang="python"] from django.utils.translation import activate activate('es-ES') [/cc] will change global …

can we merge now, pleeease ?

Category: General, sympy, Tecnologí­a

Three months after I began to write sympy.queries, I feel it's about time to include it in sympy's trunk, so today I sent for review 4 patches that implement the complete query module. It's been a lot of fun, but it has also caused me some headaches ... specially last …

Refine module, proof of concept

Category: General, sympy, Tecnologí­a

The 0.6.5 release of SymPy is taking longer than expected because some bugs in the testing framework, so my query module is not merged into trunk (yet). In the meantime, I am implementing a refine module (very little code is available yet). The refine module implements a refine …

Preparing a new release

Category: General, sympy, Tecnologí­a

Last days I've been busy preparing the first public beta of SymPy 0.6.5. Most of the time was spent solving a bug that made documentation tests fail under python2.4, but now that this is solved, I hope that by the end of the week we could have …

Efficient DPLL algorithm

Category: General

Background: DPLL is the algorithm behind SymPy's implementation of logic.inference.satisfiable After reading the original papers by Davis & Putnam [1], I managed to implement a more efficient version of the DPLL algorithm. It is 10x times faster on medium-sized problems (40 variables), and solves some wrong result bugs [2 …

Queries and performance

Category: General, sympy, Tecnologí­a

After some hacking on the queries module, I finally got it right without the limitations of past versions. You can check it out from my repo http://fseoane.net/git/sympy.git, branch master. It now relies even more on logic.inference.satisfiable(), which is just an implementation of the …