OpenCL: first investigations with an NVIDIA card

I'm taking a look at OpenCL at the moment, with the vague intention of hooking it up to Resolver One. In case you've not heard about it, OpenCL is a language that allows you to do non-graphical computing on your graphics card (GPU). Because GPUs have more raw computational power than even modern CPUs, in the form of a large number of relatively slow stream processors, this can speed up certain kinds of calculations -- in particular, those that are amenable to massive parallelisation.

Until recently, the two main graphics card manufacturers had their own languages for this kind of general-purpose GPU computing; NVIDIA had CUDA, and ATI/AMD had their Stream technology. OpenCL was created as a way of having one language that would work on all graphics cards, so although the tools for developing using it are not currently as good as those for CUDA (which has been around for a long time and has great support), as a longer-term investment OpenCL looks to me like the best one to be looking at.

It took a little bit of work to get something up and running on my machine here at work, so it's probably worth documenting to help others who are trying the same.

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Playing with NLTK

I spent some time this afternoon playing with NLTK, the Python Natural Language Toolkit; the book is highly recommended. I couldn't resist sharing the results of the first time I tried its generate function, which takes a particular text and tries to automatically generate more text in the same style.

First, from the Book of Genesis:

In the selfsame day entered Noah , and asses , flocks , and Maachah . And Joseph said unto him , Abrah and he asses , and told all these things are against me . And Jacob told Rachel that he hearkened not unto you . And Sarah said , I had seen the face of the air ; for he hath broken my covenant between God and every thing that creepeth upon the man : And Eber lived after he begat Salah four hundred and thirty years , and took of every sort shalt thou be come thither .

Next, Jane Austen:

[ Sense and Sensibility by Jane Austen 1811 ] CHAPTER 1 The family of his relations , I know Marianne ' s indisposition , beyond giving time for the world to seeing YOU .-- Very far from being weary of her feeling how more than commonly joyful . He was four years . Every thing was disregarded . I had called in Berkeley Street , January . " Mrs . Jennings , sagaciously smiling , " For my part , not being Willoughby , where much of his fate with Miss Morton , with two pointers playing round him ,

And finally, from a corpus of IRC conversations:

now im lost i agree i saw the whole thing JOIN PART google 's start page .. lol yeah , he said this morning he is hoping they win tonight im gay ....... im happy as hell ...... jus aint #### lol U42 , how are you NICK : U23 what a combo hehehe JOIN . ACTION pictures the blues brothers behind that chicken wire screen . (((((((((( U34 ))))))))))))) Hi U7 ......... how are ya ll gotta watch my manners or she wo n't you play another somebody done somebody wrong song ? JOIN . ACTION wonders if U16

Scarily accurate :-)

London Financial Python Users' Group

I clearly need to post more stuff here so that it doesn't just turn into a blog announcing the LFPUG's meetings :-)

However, in the meantime, here are the details of the next one: it'll be on 11 March 2010, and is hosted this time by Man Investments Ltd at Sugar Quay, Lower Thames Street, London EC3R 6DU. As before, all are welcome, but for security reasons you need to register in advance; just drop an email to Didrik Pinte. (Update: old mailto link removed.)

Guest of honour this time around is Travis Oliphant, the creator of SciPy and the architect of NumPy. He'll be talking about NumPy memory maps and structured data-types, and Didrik will also give a talk about integrating C/C++ libraries using Cython. More suggestions for talks (or even better, offers to give talks!) are very welcome -- once again, just email Didrik, or post something in the LinkedIn group.