Showing posts with label computers. Show all posts
Showing posts with label computers. Show all posts

The problem with "beginner's mind"

I should say up front that I know nothing about authentic Zen Buddhism. But one of the concepts that has made it into popular culture that I rather like is "beginner's mind": an expert knows what she thinks about things, while a beginner sees everything anew and judges it on what it is. It sounds kind of charming, and like a recipe for creativity. But applying it too literally can get you in trouble.

Concretely, ASTRON (where I work) arranged for a company to come in and teach programming courses to anyone who wanted them. They taught three: Introductory Python, Numeric Python, and Advanced Python. Now, I think that's a brilliant idea: we astronomers all spend most of our time writing code at one level or another, and nobody seems to have bothered to teach us how to do it well. So that ASTRON (actually NWO I think) cares is a really good sign. So of course I wanted to participate. I have lots to learn about writing good programs. I don't think I'm an expert programmer, or even a Python expert, but that latter is partly because I try not to think of myself as an expert in anything. I knew the Introductory Python course would not be productive — I write python code every day. And the Numerical Python, again, was a good idea, but having written, for example, the reshape function in numpy, and the spatial module in scipy, I figured that was probably not going to be too productive either. But the Advanced Python course sounded promising. And I wanted to show my support for the whole idea. So I signed up.

Well, the course was the last three days, and it was a pretty good course, but not at all what I needed. Which should not have been much of a surprise: when I stopped to do the math, I realize that I wrote my first python program eighteen years ago. (Good God.) Still, it was interesting to see how they ran the course, and to think about how I would run one (because if I end up somewhere like McGill that has basically nothing for physics grad students, I will run one, official or not).


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on Sunday, March 02, 2014 1 comments
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git tear-hair

I use git. It's fast, it's convenient, it gives you github, and mostly it works. But several times now I've managed to bollix a git repository, been faced with impenetrable messages, and been unable to continue using git unless I sort them out. This latest time I had enough stubbornness to figure out how to un-bollix my repository, and I wanted to record it for posterity (specifically, for people whose problem-solving technique involves Googling for the specific error message). The error I received was:
error: object file .git/objects/86/5d2dffe9a3d72917934ed9693c7167efb6d8d5 is empty
fatal: loose object 865d2dffe9a3d72917934ed9693c7167efb6d8d5 (stored in .git/objects/86/5d2dffe9a3d72917934ed9693c7167efb6d8d5) is corrupt
Read on for how it happened, my understanding of what it means, and how I fixed it. Or skip this even-more-technical-than-usual post; I'll try to post something with corals or kittens soon.

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on Friday, December 21, 2012 0 comments
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Error 451: Unavailable for legal reasons

Proposed new HTTP error code (like the well-known 404): 451 (Unavailable for legal reasons). Contains the usual hacker humour, including a thank-you to Ray Bradbury (may he rest in peace) and the following example:

HTTP/1.1 451 Unavailable For Legal Reasons
Content-Type: text/html

<html>
<head>
<title>Unavailable For Legal Reasons</title>
</head>
<body>
<h1>Unavailable For Legal Reasons</h1>
<p>This request may not be serviced in the Roman Province of
Judea due to Lex3515, the Legem Ne Subversionem Act of AUC755,
which disallows access to resources hosted on servers deemed
to be operated by the Judean Liberation Front.</p>
</body>
</html>
Of course, this particular error might have been the result of hacking by the People's Front for Judea.

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on Wednesday, June 13, 2012 0 comments
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I for one welcome our new robot overlords

Fantastic Adventures 1941 Jan cover A common theme in science fiction is the idea that robots will take over our world. This doesn't seem very likely, but suppose it were to happen. What would the first steps look like? How would we first begin to notice that it was happening?


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on Sunday, December 04, 2011 2 comments
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Breaking out of iTunes

Since I got my "new" hand-me-down smart phone, I've been listening to a lot of podcasts. The phone is smart enough to use only my home wifi to update and download episodes, and the player keeps track of which ones I've read. This is so useful, in contrast to the music player, that I found it works better to keep my audiobooks on my home server and write a quick hack to serve them up as podcast feeds. But mostly I use podcasts like radio programs. Unfortunately, some podcasts are available only through iTunes. This makes sense if they cost money, but, for example, the NASA Lunar Science Institute has a free podcast which is only available through iTunes.

Fortunately it seems that the way these places get the data to iTunes is by serving up a standard RSS feed, which iTunes then wraps up in its proprietary glop. But Michael Sitarzewski helpfully put together a script that can extract the location of the original RSS from iTunes. So, for instance, you can subscribe to the NLSI podcast here. Very nice.


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on Thursday, November 03, 2011 0 comments
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ssh shenanigans

I use ssh all the time, from simple terminal connections to VNC sessions controlling telescopes to rsyncing terabytes of data to serving my music and video library. Most of the time, the machine I actually want to connect to is not visible from the open internet, and in some cases there are two layers of machines to go through to get to the one I want. I have used various ad-hoc combinations of ssh connections, but I just found a brilliant library that solves several of my problems: paramiko.

(Also, the name is from Esperanto, and the releases are named after gashlycrumb tinies. This is some serious nerdery, here.)


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on Thursday, October 20, 2011 2 comments
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Rest in peace, Dennis Ritchie

Dennis Ritchie, who created the C language, has died. It would be difficult to overstate the importance of his work — C is imperfect and limited, but it serves as a near-universal tool for programming everything from tiny ATTiny8s to Blue Gene supercomputers. It does exactly what it was designed to do — provide a portable abstraction that is nevertheless close enough to the underlying machine to be efficient, and comfortable enough to write substantial programs in. These days, I (and many other programmers) prefer to write in Python or another high-level language, but most interpreted languages are still implemented in C, and when performance is critical, C is generally the way to go. Dennis Ritchie's impact on the world of computers was tremendous, and he will be sorely missed. 
From: Dennis Ritchie 
Newsgroups: comp.std.c
Subject: Re: Computing sizeof() during compilation
Organization: Bell Labs, Lucent Technologies

> You are right.  It was nice back in the days when things like
> 
> #if (sizeof(int) == 8)
> 
> actually worked (on some compilers).

Must have been before my time.

 Dennis

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on Friday, October 14, 2011 0 comments
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A captcha problem

Hmm. Think it would cope with \( M_2(\mathbb{Z})\tilde m \)? Or $M_2(\mathbb{Z})\tilde m$? Or just plain M_2(\mathbb{Z})\tilde m? In principle it might, since recaptcha is crowd-sourced; if I came up with the same LaTeX representation all previous recaptcha users had, all would be fine...

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on Saturday, September 24, 2011 2 comments
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Virtual idol

Years ago, I'm not sure when or where, I saw the anime Macross Plus, which is about a pop star who is entirely a computer program that sings, but who has fans as devoted as any present-day pop star. Anime being anime, there was of course a whole plot line about her AI going rogue (plus giant robots of course), but I remember thinking "how weird, a pop star who doesn't exactly exist". Well, technology progresses, and sure enough, we have one now.



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on Sunday, June 06, 2010 0 comments
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Blind Zen programming

A recent alarming network problem while trying to observe remotely at Green Bank brought back memories of the age of the 2400 baud modem, when you could often type faster than the system could display your characters. Fortunately I use the text editor vi, which was designed for these conditions. In fact, in this light some of the user interface decisions make a lot more sense.

The most prominent weird UI decision is that the editor has two "modes": insert mode, in which you can actually type text and it goes into your document, and "beep mode" in which the letters on the keyboard all tell the editor to do something (and it beeps if that something doesn't make sense). For example, to move around your document, the keys hjkl move you left down up and right, respectively. Bizarre as it may seem, these keys are on the home row, so if you're doing a great deal of moving around — particularly common when programming, i.e., debugging — this makes a certain sense. (Plus vi users get so hardwired that these become perfectly rational movement keys in video games.) The decision to have an editor-control mode also means that you don't need to press the "control", "alt", or "meta" keys very often, which makes sense since these often didn't work or were inconsistently placed on old UNIX machines. (I spent a while switching between terminals, some of which had "Caps Lock" and "Control" interchanged, and to this day I disable "Caps Lock" on every keyboard I use.)

The use of ordinary (case-sensitive) letter keys for editor commands also means that there's room for lots of editor commands, and they're very quick to use. So, for example, to search forward, you use "/"; "n" takes you to the next match and "N" to the previous. But there's also "f", which searches forward for a single character. While apparently bizarre, when combined with the ability of commands like "delete text" (d) to take an argument, this means you can do "delete up to the next single-quote" with "df'".

All this makes even more sense when it might be seconds from when you type a key to when you see its effect. So if, for example, you're typing along and you realize "hey wait, that 'a' was supposed to be an 'i'", instead of pressing the cursor keys many times and waiting to see where the cursor wound up, you can compose sequences like "Fari$", which will search back to the a, replace it with an i, and return you to the end of the current line. It's a bit like being the blind Zen archer.

All that said, I must make a peace offering to those in the emacs camp: being written not so much later, it offers similarly complex editing functionality, with similarly unusual (but different) UI decisions. I used emacs for years, switched to vi for some reason or other, and have stuck with it through inertia, mostly. (Even in the ubiquitous text boxes on the web I find myself hitting Escape followed by strings of gibberish. I'm not quite hardcore enough to go figure out how to make Firefox use vi as its editing component.)

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on Thursday, March 11, 2010 1 comments
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