Below are the 20 most recent journal entries recorded in khslinky's LiveJournal:

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Tuesday, January 27th, 2009
10:39 pm	Check Please? Tonight, Elizabeth loudly said "Check" to me in the sense of checking something off. Along the lines of "Don't believe in God--Check!" As soon as she said it, Zoë looked up from her coloring and said "peas". "What?" we asked. "Please," she repeated. "Shrek, please." As far as we know, Shrek is the only thing for which she will voluntarily say please. We explained that Mommy had said "check" not "Shrek," and that we weren't planning to watch Shrek tonight. She took it fairly well, but I was a little torn. I mean, we don't want her sitting in front of the TV all the time, and I certainly don't want to sit in front of Shrek any more than I have to (why couldn't she prefer Nemo--it's clearly the better film), but we do want to encourage her to say "please" when she wants things instead of demanding "Shrek! More Shrek!" (2 Comments |Comment on this)
Saturday, June 28th, 2008
1:25 pm	Biking I road my bike to work yesterday. It was the first time I'd ridden a bike in about 15 years, but it went okay. It took about 40 minutes to go a little over seven miles. I'm pretty sure that I can get that down under a half hour once I'm more used to biking. (I'm still getting the hang of gears—every bike I'd ever been on before had exactly two gears: sitting and standing.) (Comment on this)
Tuesday, January 1st, 2008
11:23 pm	Resolutions I don't normally go in for new year's resolutions—I figure if you want to do something, why wait for a new calendar year. On the other hand, I have a number of non-urgent things that I've been thinking I need to do eventually, and I really need to just pick a day to start doing them (lest “eventually” never come). Today seems like as good a day as any other. My resolutions are pretty concrete, and I'm going to list them here so that ohioana (and anyone else who happens to be around) can help me stick with them. ( Resolutions ) (4 Comments |Comment on this)
Friday, December 14th, 2007
11:22 pm	Volatile Function Pointers I was nearly blown away by Visual C++ this week. In the end, I was merely pleased with it, but for the space of about a half-hour, I thought Visual C++ was working magic. At work recently, one of our co-ops (for privacy's sake, we'll call him Alonzo Church) was working on printing out nice stack traces from C++ code when we throw an exception. He was testing it with something like this: f() { g(); } g() { h(); } h() { stack_trace(); } int main() { f(); } Unfortunately, the stack trace only showed h and main. Alonzo figured that f and g were missing because they'd been inlined, so he asked me if I knew of a way to turn off the inlining for just those functions without turning off optimizations altogether. I suggested that he change the calls to f() and g into indirect calls through global function pointers. There was absolutely no way, I assured him, that a compiler would inline such a call. But it did! Both f and g were still missing from the stack trace. We even declared the function pointers volatile, and defined them in separate files, and it still inlined them. (The syntax is void (* volatile f_ptr)(), by the way—it took me a couple tries to figure that out.) Now, obviously no compiler is inlining indirect calls through volatile function pointers. So what's going on? Why aren't f and g in Alonzo's stack trace? ( Answer ) (2 Comments |Comment on this)
Monday, November 19th, 2007
10:18 pm	Gelfand does Basic Algebra So I was browsing through math books on Amazon the other day, and it recommended a basic trigonometry book. I clicked on it thinking it might be the weird Australian trig book with quadrance and spread, but it turned out to be a traditional trig book. I almost closed the page, but then I saw the author's name and did a double take: Gelfand. (If you don't recognize the name immediately, it's because you haven't studied enough functional analysis.) It turns out he's written an entire series of high-school level math textbooks. How cool! (3 Comments |Comment on this)
Saturday, November 17th, 2007
8:16 pm	Hiring Programmers Some tips for anyone attempting to secure employment as a software engineer: You should know how to write a for-loop. Especially if your current title is “Principal Software Engineer.” If you claim to have worked on numerous C++ projects over the past fifteen years, you should know both (1) what a template is, and (2) what a virtual function is. And you should be able to write a for-loop. When asked to write code on a whiteboard, it's acceptable to say “A whiteboard is a less-than-ideal development environment. It will be difficult to write and debug code without my editor and compiler.” It's probably not a good idea to say “Oh man, it's been so long since I had to write code!” If asked to read a bunch of numbers from a file, your first impulse should not be to store them in a fixed-size array. Don't try to convince your interviewer that frequently copying your source code to a network location is an acceptable substitute for a revision control system. You really need to know how to write a for-loop. Now, I'm all for eliminating for-loops from your code—it's been months since I wrote my last for-loop at home. But loops are still common in professional settings, and frankly, nobody's going to believe that you're a professional programmer if you can't write one. It's harder to find good programmers than I expected. In the end, though, we did hire someone that I'm pretty excited about. (5 Comments |Comment on this)
Monday, November 12th, 2007
5:53 pm	Porn I was looking at some porn on the internet the other day. I don't think I quite understand the appeal of porn. I mean, I think of sex as touching someone that I like—looking at a stranger that I can't touch just doesn't cut it. And what's with all the shaved crotches? Half the time, I felt like I was watching middle-school girls have sex. (5 Comments |Comment on this)
Sunday, October 28th, 2007
1:20 am	Marshmallows About a year ago, I overheard someone chastising a child for (intentionally) burning a marshmallow in a fire instead of eating it, because she couldn't stand to see food go to waste. I think this is silly for a number of reasons, chief among them that it's a bit of a stretch to call marshmallows “food”. Kroger apparently agrees with me. For reasons I won't get into, I was looking for marshmallows at the grocery store tonight. My first thought was that they were a baking good, but all I could find in that aisle was marshmallow fluff. Then I thought that maybe they were an ice cream topping, but that section only had some sort of “process marshmallow food topping”—no real marshmallows. My next stop, the tea/coffee aisle, had marshmallows, but I would have had to rip open packages of hot chocolate to get them. I finally asked an employee, who told me that marshmallows were in aisle twelve. That aisle contained only baby food and toys, with marshmallows at the boundary. Since I can't imagine that Kroger thinks of marshmallows as baby food, I have to assume that they agree with me: a marshmallow is really more of a toy than a food. (2 Comments |Comment on this)
Tuesday, October 2nd, 2007
9:03 pm	Exhaustion You know how sometimes when you're sick your joints ache and your skin feels super sensitive and you don't want anything to touch you? I felt like that last night, from about four in the afternoon until I woke up this morning. Except I wasn't sick. I think Zoë has introduced me to a level of exhaustion I've never experienced before, even when I pulled all-nighters in college. (6 Comments |Comment on this)
Tuesday, September 25th, 2007
9:00 pm	Hurray for Layoffs One of the best things about working where I do is the people I work with. The development team is small, but everyone is friendly, helpful, and extremely competent. When I've thought about this in the past, I've always chalked this up to good hiring practices, but I recently started to wonder if it might have to do with layoffs. Before I joined the company, but after most of the people I work with did, there were several significant rounds of layoffs. Could it be that this left only the top talent? Once this is accomplished, it might be self-sustaining, since really good people will hire other really good people (that's what I like to think, anyway). I've always heard that it works the other way around—that once you start making cuts, everybody starts looking for other work and the best people have plenty of opportunities, so you end up losing them. But perhaps if you provide enough equity-based compensation and give your employees some reason to believe that the company is in good hands, you can avoid this. You'd have to do lots of other stuff right, too, such as figuring out who to get rid of. And of course it doesn't work at all unless you've got good people to begin with. Linguistic side note: I almost wrote “figuring out whom to get rid of,” but I just couldn't bring myself to do it. I'm not sure I know anybody personally who would find that construction natural. It sounds like something a non-native speaker might come up with. (3 Comments |Comment on this)
Monday, September 24th, 2007
8:04 pm	Wow, Ruby is slow I'd always heard that ruby's interpreter was remarkably slow, but I never really gave it much thought. I mean, people are always complaining about high-level languages being slow even when they're not, and I'd been using ruby for small projects here and there (basically as a perl replacement) since 2002 with no trouble. And when I say small projects, I don't necessarily mean that Ruby wasn't doing much work. I've processed some large chunks of text with it, but those were mostly with regular expressions that call some C library routine in the background. I recently wrote a ruby program that had to parse about five thousand lines (148KB) of XML, and I used REXML, which is written entirely in Ruby, because I was hoping this would simplify porting the program to Windows for my wife's use. Just creating a list of objects to represent all the entries in the file took eight seconds. So I did a re-write in Haskell last week. The Haskell version requires about half as many lines of code and runs in under a second. I'd avoided Haskell initially because I didn't realize there was a good Windows implementation. It's not like one of the primary authors of GHC works for Microsoft or something. (2 Comments |Comment on this)
Sunday, August 19th, 2007
11:52 am	Democratic Debate I finally got to see a presidential primary debate. (It sucks that many of the debates are only available on cable now, but that's a whole different topic.) ( My Reactions ) Linguistic side notes: Obama consistently uses a double copula. I've heard him do it before, and he did it again during today's debate. Also, several different candidates made use of the word troop to mean a single person. My (absurdly premature) prediction: Edwards will start losing ground because he's less impressive, both in presentation and (to me, at least) in substance, than Obama and Clinton. He'll then throw his support to Obama, who will take the nomination. (3 Comments |Comment on this)
Tuesday, August 7th, 2007
11:40 pm	Inheriting Points I ran into an interesting problem at work. Part of our in-house libraries is a class that represents a point in 3-space. It's nothing special: just three numbers with no other context. The problem is that the application I'm currently working on uses points in two different coordinate systems, and I occasionally found myself using the wrong kind of point in the wrong place. I'm not going to get into my eventual solution, but I didn't quite manage to solve it the way I wanted to. What I really wanted was for the type system to handle it. This is what type systems are supposed to do, right? I have two different types of things, and I want to make sure that I'm using the right one. Unfortunately, I still want to do point-like things with both of these types, and the only way to really get that behavior is to make them both subclasses of point. Which means that if I have defined point operator+( point, point ), and I do something like subclass_A + subclass_B, both types get promoted to point, and everything works just fine, which is exactly what I wanted to avoid. There are a couple different options, all unpleasant. I could go forward with subclassing point and provide overloads for any operation involving a combination of the subclasses that throws an exception (I could probably even find a way to get a compile-time error with BOOST_STATIC_ASSERT). Or I could make new classes that contain a private point member and then go through and expose by hand all of the point functionality that I want. Both of these options involve a lot of annoyingly redundant code. I could also make a very thin wrapper class with, say, a public point member, but then any code involving that class will have lots of unwrapping and re-wrapping mixed in with the actual computation. I briefly thought that I'd come up with a brilliant solution in which user-defined type conversions would allow implicit conversion from my classes into points but confuse the compiler in expressions involving points from both coordinate systems. But it didn't work because point is actually a class template, and user-defined conversion operators are applied during overload resolution, which comes after template instantiation. So when passing one of my classes to a function template that expects a point, the template can't figure out what kind of point it's looking at because the argument hasn't yet been converted to a point at all. As a side note, I think C++ is the only language I've ever used where I've made (on more than one occasion, in fact) a serious effort to confuse the compiler or trick it into doing what I wanted. Not coincidentally, it's also the only language I'm aware of where many of the standard idioms are referred to as “tricks” (e.g., the Barton-Nackman Trick and the Colvin-Gibbons Trick). (2 Comments |Comment on this)
Sunday, August 5th, 2007
6:11 pm	Baby on Board We went up to Cleveland this weekend for a wedding. According to Google, the trip from our house to the Holiday Inn Cleveland South takes three hours and seventeen minutes. When you factor in a Zoë who is slightly constipated and not at all happy about being strapped into a car seat, however, it takes closer to five hours. So we missed the actual wedding portion of the wedding. The reception was fun, but we didn't get to talk to people as much as we would have liked because we were constantly struggling to keep Zoë happy despite all the noise, the people, and the residual anger over being strapped into a car seat. The return trip also took about five hours, so the Zoë factor is at least somewhat predictable. She slept all the way to Pittsburgh when we went there over the Fourth of July. Maybe it's only North-South travel that bothers her? I'll be curious to see how she reacts to our next Pittsburgh trip. In other news, I apparently look just like someone named Austin. I was coming back to the hotel room after putting some stuff in the car this morning, and when I walked out of the elevator, a young (college-age) man said, "Hey--oh, I'm sorry. I thought you were someone else." Then his mother came around the corner, looked straight at me and said, "Are you guys downstairs?" To which her son said, "No, Mom. That's not Austin." She was shocked: "Good Lord! They could be brothers." (5 Comments |Comment on this)
Wednesday, June 27th, 2007
11:10 pm	Numbers and Factorials There's a lengthy discussion of factorial functions over at Reddit. It was inspired by a Daily WTF article in which an interviewer asked a potential employee to write a “quick function” to compute the factorial of “any given number”. The candidate failed miserably, and the entire programming Reddit is howling at the sadness of it. The problem I have with this is that, assuming the interviewer expected an answer in Java, the question is designed to produce failure. Producing a Java function to compute the factorial of “any given number” is simply not a quick or easy thing to do, especially if the candidate didn't remember the details of java.lang.Bignum. An int in Java can correctly represent the factorials of numbers from zero through (wait for it...) twelve. Java's long fares a bit better, going all the way up to 20!. This is actually a case where using floating-point numbers to represent integers is not a bad idea. With Java's double, you can represent integers exactly up to 53 bits, which is enough for 18!, and beyond that, you'll probably at least get the right order of magnitude for a while. Best of all, when the floating-point numbers finally give up on computing factorials, they'll give you infinity, which for many applications is probably a perfectly good approximation (and will almost always be better than the factorial mod 32 or 64). What I really wish, of course, is that some mainstream programming language would start giving people actual integers when all they ask for is an int. I realize that 32- and 64-bit integers have their place, but unless I ask specifically for one of those, what I really want is an integer. The integers have some wonderful properties that I've grown really quite fond of, like x < x + 1 x ≠ 0 and y ≠ 0 → xy ≠ 0 x > 0 and y > 0 → xy > 0 ∀ x, ∃ y such that y > x and, of course, n ≥ 0 → n! > 0 (2 Comments |Comment on this)
Monday, June 18th, 2007
11:30 pm	Emacs/Keyboard Trivia That stupid Windows right-click-menu key is mapped to M-x in emacs (at least on the most recent Ubuntu). If anything needs a dedicated key, that does. Almost makes me wish that I had one in a convenient location. (Comment on this)
Saturday, June 16th, 2007
4:45 pm	Parable of the Sower I finally read Parable of the Sower recently, and it was fantastic. I should have read it years ago when wynndom first recommended it to me (happy belated birthday, by the way), but I was avoiding it because I hadn't enjoyed Butler's Wild Seed very much. This isn't the first time that I've done something like that: I avoided watching Buffy for years because I'd seen the (truly awful) movie. There's probably a lesson I should be learning here. Anyway, both Parable and its sequel were excellent, and they were built around some ideas that appealed to me quite a bit (like the notion that we need to get off this planet). But they were also frightening. Parts of the story made me feel like I ought to keep some military-grade weapons around to defend my family in the event of an extended economic downturn. If you're looking for a gripping story with extremely well-drawn characters, and you're not already terrified that your home will be overrun by angry mobs and/or Christians, take a look at Parable of the Sower (2 Comments |Comment on this)
Friday, June 15th, 2007
12:18 am	Not too long ago, it occurred to me that I could recite the title of every Buffy episode in order, but I couldn't name all the U.S. presidents (in any order at all). I've finally started using the Nordic Track again (we both took a break from exercising for a while after Zoë was born), which means I've got some spare time now during which I can't really do anything useful, but my mind is basically unoccupied. I intend to use this time to memorize the Presidents of the United States along with the year each of them started to serve. Then I'm going to move on to the naturally occurring elements and their atomic numbers. Further suggestions are welcome. (6 Comments |Comment on this)
Thursday, June 7th, 2007
11:57 pm	Elizabeth has apparently been to busy to tell the latest bunny story, so I guess I'll do it. While she was mowing the lawn the other day, Elizabeth discovered that a bunny had made a nest in our yard, inside the cat fence. This bunny has been inside the fence before, and every time she comes in, she gets harassed by our cats. What would make her think it was a good idea to put a nest in our yard is beyond our limited human understanding. So Elizabeth mowed around the nest, and then went out to collect the (eight!) baby bunnies and put them outside the fence. Of course, we can't stop them from coming back inside the fence, and last night the cats had a baby bunny cornered in our bedroom in the middle of the night. Elizabeth grabbed the poor thing, put it outside the fence, and locked the cats inside the house, thereby saving the bunny. So tonight, I was going to lock the cats in before going to bed. Unfortunately, I didn't go to bed early enough, and about an hour ago Tiger was chasing a bunny around our dining room. I chased them both outside but didn't escort the baby bunny out of the fence. I figured some of those bunnies are just doomed to die on account of their mother's stupidity no matter what I do. But I just brought the cats in for the night, and Tiger seemed hungry, so maybe the little guy got away (3 Comments |Comment on this)
Monday, June 4th, 2007
9:27 pm	Programming Language Education I recently witnessed a discussion about what programming languages should be taught to impressionable young CS students. Not for the first time, I got to hear about how important it is to teach a practical language like Java in introductory programming courses. I never find the arguments in favor of Java especially convincing: it isn't actually possible to teach the average freshman enough of Java to make it a useful practical tool, and anecdotal evidence suggests that teaching students Scheme first helps them learn C++ better later on. But I can at least understand how an otherwise reasonable person could come to the erroneous conclusion that Java should be taught as a first language. What really bothers me is something I discovered today. I was talking to one of our co-ops about the classes he'd taken this quarter when he mentioned Comparative Languages. Being a PL geek, I asked him what languages they'd studied. His answer: C++, Java, C#, and a little bit of Scheme at the end. Did they cover hygienic macros or continuations or any of the really cool stuff in Scheme? Of course not. I get the feeling they just tossed enough cars and cdrs around to give the impression that Scheme is “weird” and left it at that. This is like offering a comparative religions class that focuses primarily on Catholics, Anglicans, and Episcopalians, with a little Zoroastrianism at the end to provide an example of a goofy minority faith. How do you make a 10 week long class out of that? Note to schools: If you really want to give your students a practical skill, tell them about revision control systems. I'm amazed by the number of new graduates we've interviewed that seem to have gotten all through school (sometimes even grad school) without ever encountering the concept. (5 Comments |Comment on this)