crntaylor

Joined 17 years ago

Karma

3,009

Submissions

324

Member since

May 6

http://www.linkedin.com/profile/view?id=19184234

Email at <my user name>@gmail.com

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Recent submissions

Comment · 12 years ago

London Haskell Meetup:

http://www.meetup.com/London-Haskell/

Comment · 12 years ago

Sorry I missed the talk! Did it get videoed? They usually are.

Comment · 12 years ago

The part that really surprised me was this:

  We only had 23 years of Python interpreter development,
  how would things look like when Python is 42, like C?

C, which I always think of as an ancient venerable systems language, is less than twice as old as Python, which I think of as a hot new kid on the block.

In thirty years, when my career will probably be drawing to a close, Python will be 53 years old and C will be 72 years old. Barely any difference at all.

Comment · 12 years ago

It was a reference to the Hemingway app. If you paste acqq's comment into Hemingway, it suggests "Four adverbs used. Try to aim for two or less."

As humour goes, it's a few levels of indirection away from Seinfeld. But you're on a forum full of people who spend all day thinking of abstractions for their abstractions, so what do you expect?

Comment · 12 years ago

You might not work any less hard, but you'll certainly take more risks if you don't experience the downside.

Answer quickly - how much of your net worth would you risk on a bet with 1% chance of a 1000X payout? Now how much would you risk if you can hand off 90% of any loss you take to someone else?

The difference is what we call moral hazard: http://en.wikipedia.org/wiki/Moral_hazard

Comment · 12 years ago

The investment banking industry basically invented the concept of OPM (other people's money) in the 1980s (okay, I'm sure it existed before that, but the 1980s was when it became a buzzword).

A great read if you're interested in learning more about the history and operating procedures of the sales & trading side of investment banking is Traders, Guns and Money by Satyajit Das. Its sections on credit default swaps and collateralized debt obligations are particularly interesting when you consider that they were written in 2006, pre-crisis (around the same time that Leveraged Sell Out was getting started, in fact).

Comment · 12 years ago

If it helps, you can replace "Secure" with "X" where X is any adjective, and my argument will still work.

Comment · 12 years ago

In case it's not clear to you, there are two reasons that you are getting downvoted: 1. snark, and 2. you are committing the logical fallacy of affirming the consequent. [0]

In particular, dijit asserted that "Not ACID => Not secure" (which is debatable, but that doesn't matter here) from which you can also validly deduce the contrapositive "Secure => ACID". However, you then (sarcastically) asserted that dijit is saying "ACID => Secure", whereas in fact he said nothing like that.

[0] http://en.wikipedia.org/wiki/Affirming_the_consequent

Comment · 12 years ago

You tend to hear high frequency traders refer to the code that makes pricing and trading decisions as a system, or signal, or model, or (very occasionally) algo (all refer to slightly different things) but I have never heard them refer to the code that makes trading decisions as a bot or algobot.

Source: I used to work in high frequency trading.

Comment · 12 years ago

This would have been a significantly more enjoyable experience if the title of the submission didn't give away the ending.

Comment · 12 years ago

The pattern will break down once you get past 8192, which is 2^13. That means that the pattern continues for an impressive 52 significant figures (well, it actually breaks down on the 52nd digit, which will be a 3 instead of a 2).

The reason it works is that 9998 = 10^4 - 2. You can expand as

    1 / (10^n - 2) = 1/10^n * 1/(1 - 2/10^n)
                   = 1/10^n * (1 + 2/10^n + 2^2 /10^2n + 2^3 /10^3n + ...)

which gives the observed pattern. It breaks down when 2^k has more than n digits, which happens approximately when

    2^k > 10^n   =>   k > n log(10) / log(2)

which comes out to 4 * log(10)/log(2) = 13.28 when n = 4.

---

Another pattern can be generated from the power series expansion

    x / (1 - x)^2 = x + 2x^2 + 3x^3 + 4x^4 + ...

setting x = 1/10^n gives the infinite series

    1/10^n + 2/10^2n + 3/10^3n + ...

which leads to the neat fact that

    1 / 998001 = 0.000 001 002 003 004 005 006 007...

---

Another example is the fraction

    1000 / 997002999 = 0.000 001 003 006 010 015 021 ...

which goes through the triangle numbers[0] in its expansion, or

    1 / 998999 = 0.000 001 001 002 003 005 008 013 021 ...

which goes through the Fibonacci numbers[1].

---

Getting the squares is harder, but you can do it with

    1001000 / 997002999 = 0.001 004 009 016 025 036 049 ...

[0] http://en.wikipedia.org/wiki/Triangle_number

[1] http://en.wikipedia.org/wiki/Fibonacci_number

Comment · 12 years ago

I think you mean "its a art".

Comment · 12 years ago

I think you need to parse it as

  more (portable and secure)

rather than

  (more portable) and secure

Comment · 13 years ago

Having someone re-write my 7 line Haskell program into 40+ lines of C# is the best argument I can think of for why it's worth learning a functional programming language ;)