| Andrew Cooke | Contents | Latest | RSS | Twitter | Previous | Next


Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

Personal Projects

Lepl parser for Python.

Colorless Green.

Photography around Santiago.

SVG experiment.

Professional Portfolio

Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

C-ORM: docs, API.

Last 100 entries

Small Success With Go!; Re: Quick message - This link is broken; Adding Reverb To The Echo Chamber; Sox Audio Tools; Would This Have Been OK?; Honesty only important economically before institutions develop; Stegangraphy via PS4; OpenCL Mess; More Book Recommendations; Good Explanation of Difference Between Majority + Minority; Musical Chairs - Who's The Privileged White Guy; I can see straight men watching this conversation and laffing; When it's Actually a Source of Indignation and Disgust; Meta Thread Defending POC Causes POC To Close Account; Indigenous People Of Chile; Curry Recipe; Interesting Link On Marginality; A Nuclear Launch Ordered, 1962; More Book Recs (Better Person); It's Nuanced, And I Tried, So Back Off; Marx; The Negative Of Positive; Jenny Holzer Rocks; Huge Article on Cultural Evolution and More; "Ignoring language theory"; Negative Finger Counting; Week 12; Communication Via Telecomm Bids; Finding Suspects Via Relatives' DNA From Non-Crime Databases; Statistics and Information Theory; Ice OK in USA; On The Other Hand; (Current Understanding Of) Chilean Taxes / Contributions; M John Harrison; Playing Games on a Cloud GPU; China Gamifies Real Life; Can't Help Thinking It's Thoughtcrime; Mefi Quotes; Spray Painting Bike Frame; Weeks 10 + 11; Change: No Longer Possible To Merge Metadata; Books on Old Age; Health Tree Maps; MRA - Men's Rights Activists; Writing Good C++14; Risk Assessment - Fukushima; The Future of Advertising and Surveillance; Travelling With Betaferon; I think I know what I dislike so much about Metafilter; Weeks 8 + 9; More; Pastamore - Bad Italian in Vitacura; History Books; Iraq + The (UK) Governing Elite; Answering Some Hard Questions; Pinochet: The Dictator's Shadow; An Outsider's Guide To Julia Packages; Nobody gives a shit; Lepton Decay Irregularity; An Easier Way; Julia's BinDeps (aka How To Install Cairo); Good Example Of Good Police Work (And Anonymity Being Hard); Best Santiago Burgers; Also; Michael Emmerich (Vibrator Translator) Interview (Japanese Books); Clarice Lispector (Brazillian Writer); Books On Evolution; Looks like Ara (Modular Phone) is dead; Index - Translations From Chile; More Emotion in Chilean Wines; Week 7; Aeon Magazine (Science-ish); QM, Deutsch, Constructor Theory; Interesting Talk Transcripts; Interesting Suggestion Of Election Fraud; "Hard" Books; Articles or Papers on depolarizing the US; Textbook for "QM as complex probabilities"; SFO Get Libor Trader (14 years); Why Are There Still So Many Jobs?; Navier Stokes Incomplete; More on Benford; FBI Claimed Vandalism; Architectural Tessellation; Also: Go, Blake's 7; Delusions of Gender (book); Crypto AG DID work with NSA / GCHQ; UNUMS (Universal Number Format); MOOCs (Massive Open Online Courses); Interesting Looking Game; Euler's Theorem for Polynomials; Weeks 3-6; Reddit Comment; Differential Cryptanalysis For Dummies; Japanese Graphic Design; Books To Be Re-Read; And Today I Learned Bugs Need Clear Examples; Factoring a 67 bit prime in your head; Islamic Geometric Art; Useful Julia Backtraces from Tasks; Nothing, however, is lost with less discomfort than that which, when lost, cannot be missed

© 2006-2015 Andrew Cooke (site) / post authors (content).

Using Choco

From: andrew cooke <andrew@...>

Date: Fri, 30 Mar 2012 23:27:34 -0300

I just finished (before midnight!) a solution to
http://stackoverflow.com/questions/9689436 using Choco

And it's pretty neat.

Previously, I had written a simple depth-first search and a "smart" search
with constraint propagation (along the same lines as
http://norvig.com/sudoku.html).  My DFS was fast when there were few
constraints while my "smart" routine was fast when there were lots of
constraints.  But both were disappointing when not well-matched to the

In contrast, Choco combines the best of both worlds (although the initial
startup cost is higher).  It's as fast as a simple DFS when it needs to be,
but can also exploit constraints to find quick results when possible.

Which I guess is what you'd expect.

The downside is that it's a big system, and the API docs aren't so great.
There's a manual, which is a good introduction, but when you start to explore
it can become a little opaque.  For example: it turns out that (as far as I
can tell) if you specify a set of values for a variable, they need to be
ordered.  That's not in the API docs, but without it, the system crashes.

Even so, the speed is impressive.


PS Choco is Java, but I called it from Clojure.  I really like Clojure - it
seems to hit the sweet spot of functional, untyped and, surprisingly
important, good control over evaluation strategies (lazy and eager).  It's
like a Haskell for dumb people :o)

Choco Update (and New Blog)

From: andrew cooke <andrew@...>

Date: Fri, 6 Apr 2012 20:00:40 -0300

Alas, the comments above were written in haste.  There was a bug (well,
several) in my code.  It turns out that Choco is not a magic bullet - in fact
it performs pretty much the same as my "smart" search.  Which isn't too bad or
surprising, really.

There is much, much more information in the links below, which are to a new
blog I have started with people at work.  I am not "moving" there, but will
use that to document work that involves company time (as this did - although
it also sucked up a lot of my own time, too).



Comment on this post