Andrew Cooke | Contents | Latest | RSS | 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

Choochoo Training Diary

Last 100 entries

[Programming] React Leaflet; AliExpress Independent Sellers; Applebaum - Twilight of Democracy; [Politics] Back + US Elections; [Programming,Exercise] Simple Timer Script; [News] 2019: The year revolt went global; [Politics] The world's most-surveilled cities; [Bike] Hope Freehub; [Restaurant] Mama Chau's (Chinese, Providencia); [Politics] Brexit Podcast; [Diary] Pneumonia; [Politics] Britain's Reichstag Fire moment; install cairo; [Programming] GCC Sanitizer Flags; [GPU, Programming] Per-Thread Program Counters; My Bike Accident - Looking Back One Year; [Python] Geographic heights are incredibly easy!; [Cooking] Cookie Recipe; Efficient, Simple, Directed Maximisation of Noisy Function; And for argparse; Bash Completion in Python; [Computing] Configuring Github Jekyll Locally; [Maths, Link] The Napkin Project; You can Masquerade in Firewalld; [Bike] Servicing Budget (Spring) Forks; [Crypto] CIA Internet Comms Failure; [Python] Cute Rate Limiting API; [Causality] Judea Pearl Lecture; [Security, Computing] Chinese Hardware Hack Of Supermicro Boards; SQLAlchemy Joined Table Inheritance and Delete Cascade; [Translation] The Club; [Computing] Super Potato Bruh; [Computing] Extending Jupyter; Further HRM Details; [Computing, Bike] Activities in ch2; [Books, Link] Modern Japanese Lit; What ended up there; [Link, Book] Logic Book; Update - Garmin Express / Connect; Garmin Forerunner 35 v 230; [Link, Politics, Internet] Government Trolls; [Link, Politics] Why identity politics benefits the right more than the left; SSH Forwarding; A Specification For Repeating Events; A Fight for the Soul of Science; [Science, Book, Link] Lost In Math; OpenSuse Leap 15 Network Fixes; Update; [Book] Galileo's Middle Finger; [Bike] Chinese Carbon Rims; [Bike] Servicing Shimano XT Front Hub HB-M8010; [Bike] Aliexpress Cycling Tops; [Computing] Change to ssh handling of multiple identities?; [Bike] Endura Hummvee Lite II; [Computing] Marble Based Logic; [Link, Politics] Sanity Check For Nuclear Launch; [Link, Science] Entropy and Life; [Link, Bike] Cheap Cycling Jerseys; [Link, Music] Music To Steal 2017; [Link, Future] Simulated Brain Drives Robot; [Link, Computing] Learned Index Structures; Solo Air Equalization; Update: Higher Pressures; Psychology; [Bike] Exercise And Fuel; Continental Race King 2.2; Removing Lowers; Mnesiacs; [Maths, Link] Dividing By Zero; [Book, Review] Ray Monk - Ludwig Wittgenstein: The Duty Of Genius; [Link, Bike, Computing] Evolving Lacing Patterns; [Jam] Strawberry and Orange Jam; [Chile, Privacy] Biometric Check During Mail Delivery; [Link, Chile, Spanish] Article on the Chilean Drought; [Bike] Extended Gear Ratios, Shimano XT M8000 (24/36 Chainring); [Link, Politics, USA] The Future Of American Democracy; Mass Hysteria; [Review, Books, Links] Kazuo Ishiguro - Never Let Me Go; [Link, Books] David Mitchell's Favourite Japanese Fiction; [Link, Bike] Rear Suspension Geometry; [Link, Cycling, Art] Strava Artwork; [Link, Computing] Useful gcc flags; [Link] Voynich Manuscript Decoded; [Bike] Notes on Servicing Suspension Forks; [Links, Computing] Snap, Flatpack, Appimage; [Link, Computing] Oracle is leaving Java (to die); [Link, Politics] Cubans + Ultrasonics; [Book, Link] Laurent Binet; VirtualBox; [Book, Link] No One's Ways; [Link] The Biggest Problem For Cyclists Is Bad Driving; [Computing] Doxygen, Sphinx, Breathe; [Admin] Brokw Recent Permalinks; [Bike, Chile] Buying Bearings in Santiago; [Computing, Opensuse] Upgrading to 42.3; [Link, Physics] First Support for a Physics Theory of Life; [Link, Bike] Peruvian Frame Maker; [Link] Awesome Game Theory Tit-For-Tat Thing; [Food, Review] La Fabbrica - Good Italian Food In Santiago; [Link, Programming] MySQL UTF8 Broken; [Link, Books] Latin American Authors

© 2006-2017 Andrew Cooke (site) / post authors (content).

Adaptive Computation

From: "andrew cooke" <andrew@...>

Date: Sun, 5 Mar 2006 10:12:20 -0300 (CLST)

Didn't feel like programming last night after work, so I poked around on
my disk (no internet to surf while staying at the flat in La Serena) and
found apaper I had never read, called "Adaptive Functional Programming" by
Acar, Blelloch and Harper.

It was pretty interesting.  An adaptive computation is one that changes to
reflect new inputs.  Think of a spreadsheet.  What they did (back in 2002)
was develop a library in ML that allows simple conversion from an normal
fucntional program to one that is adaptive.  In the paper they give an
example, converting a normal quicksort into an adaptive one.  The normal
code sorts a list; they adaptive code gives a list that changes when the
input changes.  Changing a single value in the input to adaptive code only
takes O(log(n)) time - the whole list is not resorted.

Best of all, the conversion is extremely simple - the adaptive code is
almost identical to the original code.

You can imagine how this works in very vague terms - instead of
constructing the code, you contruct a chain of functions with the
structure of the code, and then trigger them as necessary.

This reminded me of some thinking I did some time ago about data
processing in scientific (astronomical) pipelines.  To understand the
relevance you need to have an idea of how data reduction in astronomy is
changing.

The old way of reducing astronomy data was to work on your own computer,
manipulating the data with a fairly sophisticated set of programs.  These
were typically split into tasks and an astronomer would spend a fair
amount of time running different tasks, tweaking parameter values,
re-running, and generally getting a good idea of how the reduction process
affected the results.

The new way of reducing astronomy data is to use a dedicated pipeline at
or near the telescope.  The pipeline is developed and operated by the
observatory; the astronomer receives processed data as a "product".

Now it's not clear to me why an astronomer cannot run a pipeline locally,
at their own department.  A local pipeline combines the advantages of both
approaches above - it gives a default "product", but also allows tweaking
by the user.

OK, how does this fit in with adaptive computing?  Maybe it's already
obvious - adaptive computing would improve the efficiency of a local
pipeline when the astronomer wants to "tweak" parameters.  Instead of
repeating the reduction of all the data, only those parts that depend on
the changed parameters would need to be re-run.

Of course, that wouldn't work with the pipelines we develop at NOAO, since
they are built using a system that doesn't abstract away the distributed
nature of the system - different processes run on different machines, and
communication is "outside" the language used for implementation (the
technology is basically Fortran 66).

But you could imagine doing the same thing with a system that incorporated
distributed processing inside the language - perhaps something built with
Erlang, for example.  Then adaptive computations could exist across a
network of machines.  That would be amazingly cool.  If any forward
thinking observatory wants such a system, email me... :o)

The paper itself is available in PDF form at
http://www.cs.cmu.edu/~umut/papers/popl02.pdf (or Google for the title).

Andrew

Comment on this post