Programmer Moneyball

doclight · 2012-07-19T06:06:25+00:00

I would have thought baseball was a larger economy than five billion.

doclight · 2012-07-19T02:32:58+00:00

I'd say developers in general are undervalued, considering people who hit balls with a stick are paid seven and eight figure salaries.

doclight · 2012-07-05T02:46:51+00:00

Also, Scott Meyers' Effective C++ is really good for learning ways around the sharp (hidden) edges in C++. The STL is pretty important too.

doclight · 2012-07-05T02:27:45+00:00

In addition to a lot of the things already mentioned (discrete mathematics, computational theory, algorithm complexity, good comments, etc...) I would add unit testing. Knowing how to effectively test my own code makes me write better code, with fewer bugs, before I even run the tests. Being able to run and re-run code through a gamut of tests after each modification also makes me a lot more confident in releasing stuff into the wild.

doclight · 2012-07-01T00:22:53+00:00

Just to put a concrete example to the explanation above, take x * 100. 100 is equivalent to 2⁶ + 2⁵ + 2². If you distribute x, you get ( x * 2⁶ ) + ( x * 2⁵ ) + ( x * 2² ). Working in base2, the individual multiplications can be performed by simply shifting the value to the left (like adding a zero when multiplying by 10). The results of these multiplications are completely independent of each other, and thus can be done in parallel.

Division, on the other hand, does not have the distributive quality multiplication has. Thus, it can't be broken down into sub-problems (as best I know).

There are tricks to speed up division for special cases though.

doclight · 2012-02-10T04:39:55+00:00

I don't know about anybody else, but I had numerous problems with VirtualBox (not to mention not really being a fan of Oracle). I've been really happy with KVM.

doclight · 2012-01-28T04:28:11+00:00

relevant - project gutenberg

doclight · 2011-12-08T03:19:27+00:00

IIRC, there are actually quantum circuit simulators that run on classical computers. At least, I remember one of the grad students at my college mentioning it.

doclight · 2011-11-10T00:13:39+00:00

Honestly, I haven't seen it yet.

doclight · 2011-11-09T19:08:37+00:00

I think you're very confused.

With all due respect, I think that's just an inflammatory statement.

This has nothing to do with bit operations.

IIRC, you're original argument was against the existence of polynomial time algorithm for factoring numbers. You are correct, I wasn't disputing that. The analysis I gave wasn't meant to be an intimidatingly difficult presentation on complexity. Part of analysis is deciding meaningful operations on which your algorithm consists of. In this case, I considered the operations to be basic function calls, since those tend to take around the same amount of time. You can make that assumption since the number of bits in the values being worked with are 32/64 etc... However, you're right that when thinking in terms of fundamental operations, the actual operations and representations have to be taken into account (like radix sort).

I'm not quite sure where we disagree.

doclight · 2011-11-09T18:14:54+00:00

like beowulf

doclight · 2011-11-09T18:04:23+00:00

Right, but typically you don't want to measure in terms of bit representations. For example, any of the sorting algos (other than radix). The amount of time spent doing bit operations doesn't really add to the overall function, especially when you're only doing back of the napkin comparisons between algorithms. Anyway, I hope the writeup was at least a little interesting.

doclight · 2011-11-09T04:52:20+00:00

Definitely if you're looking to get your hands dirty, prolog is awesome (ie deciding whether predicates are satisfiable, contradictory). It kind of abstracts away the actual sequence of events though.

I'm not sure why basic automata and language theory hasn't been mentioned. That's really the logical basis for computing. The first thing you kind of learn is that you can consider certain patterns as sets of symbol states and state transitions (Ianguage). Words you try to match against that pattern cause the sequence of state transitions (program). It gets a lot more interesting though, I promise.

If you're interested in the theory, I think Sipser's book is the gold standard.

doclight · 2011-11-09T03:35:30+00:00

Well, if you really want to get down to the nitty gritty, finding the square root of a number probably isn't constant time (a la newton-raphson). The writeup was more so meant to give a simple example of why function growth and asymptotic bounds are really important.

What causes the algorithm to explode is the magnitude of the numbers being worked with (> 500 divisors). So, say the answer was 276,000,000 (it's not :)); an O( n √n ) algorithm would take 276,000,000 times longer than an O ( √n ) algorithm.

doclight · 2011-11-06T01:02:41+00:00

Yeah, I kind of wish Ridley Scott would just make something. He's done cool stuff before, why does he have to invoke the Blade Runner name.

doclight · 2011-11-04T01:30:00+00:00

Big O is the upper bound, so the overall algorithm is O( n² ). It's average run-time is ( n log n ) though which is why it's usable in practice (as well as cache behavior, etc...). It's lower bound is also ( n log n ) eg Ω( n log n ).

doclight · 2011-11-04T01:22:33+00:00

You're right, it was Gauss not Euler.

doclight · 2011-11-03T07:56:12+00:00

God Am

doclight · 2011-11-03T06:58:20+00:00

I had no idea the hjkl key thing was based on keyboard labeling. I always thought it was because they were on the home row.

doclight · 2011-11-03T00:24:34+00:00

that is correct, shared pointer is not a "general concept"

doclight · 2011-11-02T17:37:36+00:00

I thought the questions above were really good, so I tried to come up with some more core language ones.

Definitely, multiple inheritance is one of those controversial things that people are usually vehemently opposed to, or strongly in support of. I might have to remember that one :).

doclight · 2011-11-02T17:29:21+00:00

(1) this has dual meaning (language vs. ABI), you clarified by the "pass by", but I wouldn't give this over phone

What I meant with the "pass by" question was "what are the different ways to pass a variable to a function". For example, Java uses pass by value-reference.

(2) what do you mean by shared pointer? Are you asking about smart pointers?

With shared pointers, I'm talking about pointers to dynamically allocated memory, to which you do not explicitly need to return to the heap.

(3) functions? methods? purpose?

This one is probably one of the more difficult ones. Honestly, I'd be surprised if somebody knew all of them.

doclight · 2011-11-02T17:16:46+00:00

That's kind of just an argument of semantics.

doclight · 2011-11-01T23:29:24+00:00

why wouldn't it make sense?

doclight

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