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

C[omp]ute

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

Transcript of German Scientists on Learning of Hiroshima; Calvert Journal; Telephone System Quotes for Cat Soft LLC; Owen Jones on Twitter; Telephone System Quotes for Cat Soft LLC; Possible Japanese Authors; Complex American Literature; Chutney v5; Weird Componentized Virus; Interesting Argentinian Author - Antonio Di Benedetto; Useful Thread on MetaPhysics; RAND on fighting online anarchy (2001); Now Is Cat Soft LLC's Chance To Save Up To 32% On Mail; NSA Hacked; Call Center Services for Cat Soft LLC; Very Good LRB Article on Brexit; Nussbaum on Anger; Credit Card Processing for Cat Soft LLC; Discover new movies on demand in our online cinema; Tasting; Credit Card Processing for Cat Soft LLC; Apple + Kiwi Jam; Hit Me; Increase Efficiency with GPS Vehicle Tracking for Cat Soft LLC; Sudoku - CSP + Chaos; Recycling Electronics In Santiago; Vector Displays in OpenGL; Call Center Services for Cat Soft LLC; And Anti-Aliased; OpenGL - Render via Intermediate Texture; And Garmin Connect; Using Garmin Forerunner 230 With Linux; Payroll Service Quotes for Cat Soft LLC; (Beating Dead Horse) StackOverflow; Current State of Justice in China; Now Is Cat Soft LLC's Chance To Save Up To 32% On Mail; Axiom of Determinacy; Ewww; Fee Chaos Book; Course on Differential Geometry; Increase Efficiency with GPS Vehicle Tracking for Cat Soft LLC; Okay, but...; Sparse Matrices, Deep Learning; Sounds Bad; Applebaum Rape; Tomato Chutney v4; Have to add...; Culturally Liberal and Nothing More; Weird Finite / Infinite Result; Your diamond is a beaten up mess; Maths Books; Good Bike Route from Providencia / Las Condes to Panul\; Iain Pears (Author of Complex Plots); Plum Jam; Excellent; More Recently; For a moment I forgot StackOverflow sucked; A Few Weeks On...; Chilean Book Recommendations; How To Write Shared Libraries; Jenny Erpenbeck (Author); Dijkstra, Coins, Tables; Python libraries error on OpenSuse; Deserving Trump; And Smugness; McCloskey Economics Trilogy; cmocka - Mocks for C; Concept Creep (Americans); Futhark - OpenCL Language; Moved / Gone; Fan and USB issues; Burgers in Santiago; The Origin of Icosahedral Symmetry in Viruses; autoenum on PyPI; Jars Explains; Tomato Chutney v3; REST; US Elections and Gender: 24 Point Swing; PPPoE on OpenSuse Leap 42.1; SuperMicro X10SDV-TLN4F/F with Opensuse Leap 42.1; Big Data AI Could Be Very Bad Indeed....; Cornering; Postcapitalism (Paul Mason); Black Science Fiction; Git is not a CDN; Mining of Massive Data Sets; Rachel Kaadzi Ghansah; How great republics meet their end; Raspberry, Strawberry and Banana Jam; Interesting Dead Areas of Math; Later Taste; For Sale; Death By Bean; It's Good!; Tomato Chutney v2; Time ATAC MX 2 Pedals - First Impressions; Online Chilean Crafts; Intellectual Variety; Taste + Texture; Time Invariance and Gauge Symmetry; Jodorowsky

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

RXPY Update - Beam Engine

From: andrew cooke <andrew@...>

Date: Fri, 16 Jul 2010 14:07:59 -0400

A short update on the pure-Python RXPY regular expression engine.

I just got the beam-width engine working.  This uses the "re2" approach, in
a very general sense, but differs in that:
- all state is tracked (so nothing is excluded from regular expressions)
- the maximum number of states is restricted using a "beam search" approach

The aim has been to investigate different high-level, full featured
approaches, before worrying about low-level optimisations.  And the latest
results are pretty cool - all my stress tests are handled nicely by the beam
search approach.  I'm sure I could construct problem cases, but this is
already better than a backtracking approach.

Next step is to define a set of benchmarks and formally compare the different
approaches.  After that, with uncertain priority, I need to (a) start
discarding features for speed and (b) look at pypy.

I was going to end there, but realised I haven't explained what I mean by
"beam search".  The idea is that "re2" accumulates different states,
effectively doing NFA->DFA conversion "on the fly", but that the number of
states is restricted (to 1,2,4,8... states).  This reduces the time spent
searching for (possibly exponential?) alternatives in most normal cases.

Andrew

Comment on this post