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Con la pasta por delante - Día cero
En la ciudad fabrican a las personas en serie. En el campo, los siguen haciendo a mano: los moldean, los secan al sol y luego los pintan, por eso son tan especiales. Primer concierto de la nueva gira...
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Con la pasta por delante - día 2: Martos
Después de Mengíbar vino Martos. En este caso se trataba del "Blooms Day", un sitio para el que "un pub irlandés" es una descripción aceptable. Llegamos primero Oscar y yo, en una de esas raras...
View ArticleDjango and request.POST
I spent a lot of time trying to figure out why django removed the '+' character from the POST data retrieved via request.POST. Still don't know the reason of this behaviour, but using...
View ArticleGoogle Summer of Code
First post on my GSOC adventure. This year I got accepted in Google's summer of code program as student, and my job will be to implement the assumptions framework in SymPy. Although the project...
View ArticleLogic modules in python
As a prerequisite of my GSOC project I have to do some modifications on sympy's current logic module (see previous post), so I decided to go out and take a look at what others are doing in this area....
View ArticleBoolean algebra, first steps
The first task for my Summer of Code project is to write a nice boolean algebra module. I wanted a clean module that follows SymPy's object model and that plays well with other objects. In practice...
View ArticleFun with the new Logic module
The logic module is slowly becoming useful. This week I managed to get some basic inference in propositional logic working. This should be enough for the assumption sysmtem (although having first-order...
View ArticleHomenaje a Antonio Vega en La Percha
El pasado jueves estuvimos en La Percha tocando algunas canciones de Antonio Vega. El vídeo se lo ha currado mi padre mezclando el sonido del directo con una grabación que hicimos en casa de Migue LOS...
View ArticleAssumption system and automatic theorem proving. Should I be learning LISP ?
This is the third time I attempt to write the assumption system. Other attempts could be described as me following the rule: “For any complex problem, there is always a solution that is simple, clear,...
View ArticleInitial implementation of the query system
I sent some patches to sympy-patches with an initial implementation of the query system. You can check it out by pulling from my branch: git pull http://fseoane.net/git/sympy.git master into your sympy...
View ArticleThe boolean satisfiability problem
Most annoying problem in my implementation of the query system is that it will not solve implications if the implicates are far away from each other. For instance, if the graph of known facts is...
View ArticleLogic module merged
Yesterday I finally merged the logic module in sympy's official master branch, and should be released together with SymPy 0.6.5. Next thing to do: profile the code and write some docs before the release.
View ArticleReading CNF files
The DIMACS CNF file format is used to define a Boolean expression, written in conjunctive normal form, that may be used as an example of the satisfiability problem. The new logic module (sympy.logic)...
View ArticleQueries and performance
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...
View ArticleEfficient DPLL algorithm
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...
View ArticlePreparing a new release
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...
View ArticleRefine module, proof of concept
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...
View Articlecan we merge now, pleeease ?
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...
View Articledjango, change language settings dynamically
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...
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