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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.

Recent Threads

[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

[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

[Book, Link] No One's Ways

[Link] The Biggest Problem For Cyclists Is Bad Driving

[Computing] Doxygen, Sphinx, Breathe

Recent Replies

Get Coffee Quotes for Cat Soft LLC

Mass Hysteria

VirtualBox

Update: Lower Pressures

Farellones Bike Park

Update: Second Ride

Chutney v6

Even

C++ - it's the language of the future

Learning From Trump

And

Also

Oh Metafilter

Prejudice Against The Rurals

Also, Zizek

Trump

Chutney v5

Tasting

Hit Me

And Anti-Aliased

And Garmin Connect

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

[Maths, Link] Dividing By Zero

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Previous Entries

For comments, see relevant pages (permalinks).

[Book, Review] Ray Monk - Ludwig Wittgenstein: The Duty Of Genius

From: andrew cooke <andrew@...>

Date: Fri, 3 Nov 2017 08:59:38 -0300

This is a curious mix of a book.

On the one hand, it's well written - clear and coherent.  A deftly
constructed account of Wittgenstein's life, painting an apparently
complete picture of its subject.

On the other - at least to this reader - it fails to explain exactly
why Wittgenstein was (and is) so admired.  Trudging through the
details of his obsessions, neuroses and fears, you begin to wonder why
you are spending so much time (~600 pages) on such an unpleasant
person:

 * Someone who gave up a huge amount of wealth, but continued to
   assume the privilege and standing of his birth, repeatedly relying
   on the influence of friends in high places.

 * Someone pathetically useless in social situations who felt
   qualified to tell others how they should behave.  Who was incapable
   of being a good teacher yet encouraged others to follow the same
   path.

 * Someone who intimidated and brow-beat.  Whose philosophy appears to
   be "I am right, you are wrong, but I cannot explain why."

 * Someone who felt they were making major contributions to the
   philosophy of mathematics yet lacked the technical ability to
   understand Godel's work.

 * Someone who could only connect emotionally with those who were
   younger, weaker, and easier to intimidate.

A thoroughly unlikeable man.

I am not arguing that only the nicest people should have biographies,
but perhaps the author should more clearly explain why they are
interesting.  Reports of "genius" from others in the same privileged
milieu are not enough.

Andrew

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[Jam] Strawberry and Orange Jam

From: andrew cooke <andrew@...>

Date: Sat, 28 Oct 2017 22:07:03 -0300

Made this about a month ago, but just realised I hadn't made a note of
the ingredients.  So, before I forget:

 2kg Strawberries
 1kg Oranges
 2kg Sugar

Weights are prepared fruit.  Wash the strawberries, remove the leaves,
and chop roughtly.  Wash the oranges well (to remove wax), cut off the
rind thinly and chop to fine pieces, remove the pith and cut out the
segments - cook the fruit (not the pith) and chopped rind.

The taste was difficult to imagine beforehand, but in retrospect is
obvious - orangey strawberry.  Imagine a strawberry jam made with
orange liquer, for example.

(The reason for this odd combination is that strawberries appear early
and there's not much else to combine them with).

Saw peaches at the market today, for the first time this year (which
reminded me to write this) so will make some peach jam next weekend :)

Andrew

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[Chile, Privacy] Biometric Check During Mail Delivery

From: andrew cooke <andrew@...>

Date: Thu, 26 Oct 2017 21:06:56 -0300

I live in Santiago, Chile, and just received an Amazon delivery, via
Landmark postal.  I don't know what company handles the delivery
locally, but the delivery person carried a plastic tray that held a
smartphone and a fingerprint reader.  He asked for my RUT (the state
ID number, used throughout Chilean society as a way of identifying
people, and quite a normal request when a registered package is
delivered), entered that number into the phone, which then paused
(making a request to a server for appropriate data?) before prompting
me to place my index finger on the reader.  Apparently that validated
that I was who I claimed to be and I received the package.

You may wonder where the fingerprint data comes from.  A similar
process is used to identify users when claiming medical insurance here
(eg when paying for a visit to the doctor).  So perhaps that company
is now sharing data?  Or maybe this is separate and this first scan
was not verification, but entering me into a new database?  Unlike the
medical insurance readers, this reader had no disclaimer or small
print with details of who was recording the data, or what conditions I
was implicitly agreeing to.

(Our identity cards also carry fingerprint data, but I am pretty sure
that is a thumb print, which has legal conotations here.  For example,
at a notary, I have to both sign and thumb-print important documents).

Andrew

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[Link, Chile, Spanish] Article on the Chilean Drought

From: andrew cooke <andrew@...>

Date: Thu, 26 Oct 2017 21:05:18 -0300

http://ingenieria.uchile.cl/noticias/138171/columna-de-opinion-de-la-megasequia-a-la-mediasequia

Andrew

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[Bike] Extended Gear Ratios, Shimano XT M8000 (24/36 Chainring)

From: andrew cooke <andrew@...>

Date: Wed, 25 Oct 2017 10:30:48 -0300

I've been frustrated with the highest gear of my Shimano 2x11 XT M8000
drivetrain, which uses the lowest stock 24/34 chainrings and an 11-42
cassette (with a 2X front pull, high cage derailleur and the long SGS
rear derailleur).  Compared to my old 3x9 setup I spin out
significantly earlier on downhills (the gearing on the new 2x11 was
chosen to match the lowest gear on the 3x9).


So I tried changing the front chainrings to 24/36, and have been very
pleasantly surprised by the results.

First of all, everything works fine - I noticed no difference in the
quality of the gear changes, despite the front derailleur being
specified for a maximum change of 10 teeth.

Second, the difference feels like a BIG improvement, despite the
figures (below).  This was surprising and I have the following
tentative explanations:

 * Maybe Chilean roads, or at least the routes I ride, are built so
   that the steepest parts were just outside my gear range (and are
   now just inside)?

 * Maybe there's a "terminal velocity" where wind resistance (for me,
   on my bike, in my riding position) imposes an upper speed limit
   that was just beyond my original gearing, and that is now
   achievable.

 * Maybe it's just the shock of the new and I am over-estimating its
   significance.

Whatever the reason, this feels like a big improvement: I have new PRs
(without even trying!) and can pedal pretty much constantly on my
common routes.


The numbers, however, are not startlingly different.  Below I give the
log of the gain ratio for various combinations of gears.  You don't
need to know what it means - just that it's a measure of how "fast"
each gear is:

                  Old 24/34     New 24/36

   big top        -0.69         -0.63
   big top-1      -0.86         -0.80
   big top-2      -1.00         -0.94
   big top-3      -1.12         -1.07
   
   small top      -1.04         -1.04

Which shows that:

 * The additional range is small - about 1/3 of a gear (0.06 v 0.17)

 * Previously, the small chainring ratios sat nicely between the big
   chainring ratios, effectively giving very closely spaced gears (if
   you constantly switched between chainrings).  That is no longer the
   case.

Note that the rear derailleur capacity is 47, so there is no problem
there - the only limitation is the front derailleur.


Disclaimers:

 * I made the change at the same time as changing the front derailleur
   (the spring broke on the previous one), rear derailleur (bent) and
   rear cassette (worn).  So the entire drivetrain is new (apart from
   the cranks and shifters - I also changed the cables).

 * My bike has a Boost rear hub but normal front derailleur mount /
   bottom bracket (this is standard for 2017 Cotic Soul).  So my
   chainline is not "correct".

Andrew

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[Link, Politics, USA] The Future Of American Democracy

From: andrew cooke <andrew@...>

Date: Fri, 13 Oct 2017 20:38:50 -0300

[...] the problem of “intolerant communities,” and he says there are
two such communities in America today: “identitarian” activists
concerned with issues like racial/gender equality, and the “nativist”
coalition, people suspicious of immigration and cultural change.

Each of these communities defines itself in terms of its opposition to
the other. They live in different worlds, desire different things, and
share almost nothing in common. There is no real basis for agreement
and thus no reason to communicate.

The practical consequence of this is a politics marred by
tribalism. Worse, because the fault lines run so deep, every political
contest becomes an intractable existential drama, with each side
convinced the other is not just wrong but a mortal enemy.

https://www.vox.com/2017/10/13/16431502/america-democracy-decline-liberalism

Andrew

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[Review, Books, Links] Kazuo Ishiguro - Never Let Me Go

From: andrew cooke <andrew@...>

Date: Wed, 11 Oct 2017 14:52:27 -0300

By chance I was reading Ishiguro's Never Let Me Go when it was
announced that he had won the Nobel Prize for Literature.

It's the first book of his that I've read, and I had to read it quite
slowly, to reflect on what I was reading.  After I finished I went
online and searched for some reviews:

https://www.theguardian.com/books/2005/feb/26/bookerprize2005.bookerprize

https://www.lrb.co.uk/v27/n08/frank-kermode/outrageous-game
https://www.theguardian.com/childrens-books-site/2016/jul/04/never-let-me-go-kazuo-ishiguro-review
http://www.nytimes.com/2005/04/17/books/review/never-let-me-go-when-they-were-orphans.html
http://www.independent.co.uk/arts-entertainment/books/reviews/never-let-me-go-by-kazuo-ishiguro-746328.html
https://www.newyorker.com/magazine/2005/03/28/something-about-kathy

http://www.washingtonpost.com/wp-dyn/articles/A54996-2005Apr14_2.html

The last of these is particularly poor, with at least two factual
errors, but all of them except M John Harrison's - the first - seem to
miss the point, which is that this book is a study of repression: both
self-repression and repression by society as a whole.

Anyway, the book is tremendous.  Powerful, thought provoking,
horrifying, depressing.  By far the best book I have read in some
time.

Andrew

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[Link, Books] David Mitchell's Favourite Japanese Fiction

From: andrew cooke <andrew@...>

Date: Wed, 4 Oct 2017 17:36:39 -0300

https://www.avclub.com/david-mitchell-on-his-5-favorite-japanese-novels-1798272376

Permalink

[Link, Cycling, Art] Strava Artwork

From: andrew cooke <andrew@...>

Date: Tue, 26 Sep 2017 20:50:00 -0300

https://strartwork.com/

https://www.reddit.com/r/Strava/comments/72kehs/ive_made_a_website_to_generate_digital_artwork/

Andrew

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