# The Spectre of Math

## March 20, 2009

### cvs vs. svn vs. git

Filed under: Hacking,Personal — jlebl @ 7:51 pm

I don’t get this.  So GNOME is yet again switching repositories, this time to git.  I know I spent a lot of time working with CVS when I was still very active on GNOME, and trash talking it made wonderful topic for conversation in your local pub.  But any pain associated with switching to anything else is not outweighted by any benefits.  OK svn was better.  So what.  For 99.9% of stuff, CVS does fine.  Same story with git.

Don’t fix it if it aint broke.  CVS is stupid at times, but it certainly ain’t broke.  It is extremely well tested and has not given anyone any data corruption.  The switch to SVN was a lot of pain for those involved I assume and there were some problems for some files.  SVN is far less tested for doing bad stuff to your data, simply because of its age.

OK, so now we have switched to SVN and they (I am saying they since I guess I can’t consider myself part of the active GNOME developer corps) are switching to git.  I still work on genius and very rarely on gob, so I still use the gnome repository.  For me, actually svn was slightly more annoying than CVS.  I’m fine with doing file moves on the repository or by deleting the file in the repository and checking it in under a new name.  I am not such a perfectionist.  I don’t expect someone to try to check out a working copy of GNOME 0.13 or some such.  File history beyond a few years is probably useless fluff.  So I didn’t quite see any benefit of moving away from CVS.  But oh well, who cares.

Now git.  Hmmm.  This seems like a completely different beast meaning I’ll have to waste more time learning something new to do essentially the same thing with no new benefit.  Why not move only those projects whose maintainers want to work in git, and leave those projects whose maintainers are happy with SVN in SVN?  Hmmm.  Ultimately I don’t care that much, I’m just annoyed.  And I’m worried about data integrity of the little stuff I have in GNOME SVN.

Nobody can explain to me any actual advantages of git over svn or cvs.  The only benefit I see is that git does things in a way that someone happens to think is the “correct way.”  This is like th argument that gdm must use dbus for internal chatter of greeter with the daemon or within the daemon’s processes.  There is no practical upside except someone’s warm feeling.  Downside is always instability and breakage.

Just ranting … Ignore me …

### 199 pages

Filed under: Mathematics,Teaching — jlebl @ 4:56 pm

That’s what I am up to in my diffy q’s notes. Well true it’s 12pt font (but smaller than standard latex margins) so that I can check them when teaching, and some pages are skipped due to the thing being typeset in the book class without openany option.  But it would be over 190 even with openany.  The Fourier series chapter is still mostly missing, but all the other chapters are more or less finished.  I guess I am now a week ahead in class preparation now, plus I have the Sturm-Liouville all typed up from last semester, so it will start getting simpler and simpler.

Yes, I’m now obsessed with polishing them.  Too bad these notes are for engineers.  it would be wonderful to be able to get more in depth with some of the more fun aspects.  I guess even I would learn a lot then.

### I don’t call much

Filed under: Personal — jlebl @ 3:49 pm

So I just got this voice on my cellphone telling me that my minute balance is low.  I have a prepaid and usually by for $100 worth of minutes which I normally spent in about 9 months to a year. I ignored it for a few days (I don’t call much) and I went on the website. And wow, I find out I had 488 minutes remaining (basically I used up only about 500 minutes in the past year) but the minutes were about to expire tomorrow. I put in an additional$50 (I guess for the next year).  I gotta say, that’s a cheap plan 🙂

Apparently 500 is not enough for some people for even a month.  I think my brother goes through a thousand or two each month.  Well this is probably the result of living in a small midwest town and riding a bike to work so we almost never have to call each other with Marketa to pick each other up or some such.  1000 in 9-12 months was my San Diego average.

## March 9, 2009

### Calculus dilemma

Filed under: Mathematics,Teaching — jlebl @ 3:50 pm

So I can’t quite decide what to call integration/antidifferentiation in the notes.  I have always used integrate with the understanding that it means to compute the Riemann integral and thereby compute the antiderivative by FTC.  That is, writing the indefinite integral as a shortcut for the actual integral:

$\int f(x)~dx = \int_{x_0}^x f(t)~dt + C$

But it seems that when students hear “integrate” they really think just of symbolic antidifferentiation.  I could change all instances of “integrate” to “antidifferentiate.”  But in places it just sounds bad.  I feel like I want to actually integrate at places because I want to “compute” the actual functions.  To me “antidifferentiation” smells of trying to get a closed form expression in terms of elementary functions or some such.  As an analyst I want to always just “integrate.”

Also if I change to the word “antidifferentiate,” then the whole “integrating factor method” sounds off.

## March 8, 2009

### information

Filed under: Politics,Technology — jlebl @ 4:58 pm

So apparently people can find secret military bases using google earth.  Hmmm.  Before it was “blurred.”  Hmmm.  OK, suppose I really was looking for secret sites, even with google cooperating and bluring those sites.  Isn’t it just a matter of finding the blurred sites?  I’m sure it’s actually harder to recognize a secret base if it’s not blurred than just looking for places that are blurred.  Remember that lack of information is information.

If they really want their stuff to be hidden, then provide google with doctored up photos that clean up what’s there.  Or hide it better so that you can’t recognize it so easily.

It reminds me of the policy until ’89 in czech.  You were not allowed to photograph damns, railway stations, and similar buildings.  Apparently if someone saw a turisty shot of a small town railway station they could mount an attack that would defeat communism.  Actually that’s not fair to the commies (not that I’d want to be fair to them), but this was the rule since the austrian empire.  I wonder what Franz Joseph would think about google earth.

## March 6, 2009

### It’s all Obama’s fault

Filed under: Economics,Politics — jlebl @ 6:07 pm

So apparently now (less than two months after entering office) it all became Obama’s fault.  I understand that some people think his policies will be disastrous, but use a bit of logic.  You are losing credibility by the minute.  If you think the economy will be a disaster in a few years because of what he does, wait for it, or say that.  Saying that Obama was destroying the economy before he even entered office will just mark you as a looney.  These are the same people who say the economic boom under Clinton had nothing to do with Clinton, because apparently presidents do not affect the economy.  Go figure.

## March 3, 2009

### Rush is a communist

Filed under: Economics,Politics — jlebl @ 5:43 pm

The clips from the recent republican convention thing remind me of clips one heard from the communist gettogethers before ’89 in czech.  Actually I think these are exactly the same people.  They are all conservatives, and they like telling others what to do.  Communists (at least the ones in power in czech) had a slightly different economic model, but overall it was actually similar.  Those with power and money should keep it and everyone else should stay where they were.  They both lie about this (the republicans are a bit more honest in this point).  On the other hand, the communists didn’t pretend to support individual freedom, which the republicans keep talking about while at the same time trying to prohibit anything that they don’t think people should do (you are free to do whatever, just as long as I think you should be allowed to do it).

Anyway, same people.  I think Rush would be very happy as a communist (not a true communist mind you, but the kind that ruled eastern europe).

I also enjoy republicans being the pansies now.  If any one of them does anything that insults Rush and he call them on it, they come brownnosing back to him with apologies.  For a party that prides itself on being tough and manly, they are really a bunch of pussies.  I love it.  Every time some republican has to apologize to their overlord Rush, I laugh my ass off.  This would be like democrats apologizing to Keith Olberman or some such (I’d be laughing too if that happened).

And yesterday, the stockmarket went down another year (it was ’97 in the morning and ’96 by the evening).  We are getting into Bill’s first term now.  Maybe dubya wanted to make a connection with his dad by putting the economy about where it was when HW lost.  Too bad he didn’t get to finish it during his tenure.  I’m sure he tried hard, he should get an award for trying.

## March 2, 2009

### The incomplete notes are up…

Filed under: Mathematics,Teaching — jlebl @ 10:32 pm

I figured the students would appreciate these DE notes before the end of the semester (and perhaps before the second midterm) so I put up what I have from the notes so far.  With obvious warnings of course.  The link is http://www.math.uiuc.edu/~jlebl/286notes/ (license is cc-by-sa, so freely available and usable).  They keep changing frequently and are full of typos still.

That brings me to my matrix theory notes.  Hmmm.  I think I’ll make those readable for the fall semester as I may end up teaching that again.  So no point in polishing those.  Now as to my SCV notes plan, I may have to postpone this.

## March 1, 2009

### “Short” notes

Filed under: Hacking,Mathematics — jlebl @ 5:21 pm

So this semester I am typing my notes for the differential equations notes.  I wish I did that last semester, it would make preparation easier.  Anyway, I’m a damn perfectionist and once I see the notes all nice and typed up, they look too professional not to polish them up a bit more and post them.  I’m perhaps halfway through the semester and the thing is like 80 pages already (12 pt font).  I thought these would be short class notes.  Anyway, I’ll post the pdf/latex once it’s a bit more polished (I only have what I have taught so far plus those that I typed last semester, minus those that I used handwritten notes for this semester).  I guess the students might want to look at these notes and I only have some of them online so far.

The damn perfectionist part of me makes sure that I obsess about making the notes more polished and more complete even if I don’t really have to, and I don’t really have time to.  Oh well.  Not that there are no free notes for DE out there, but one more set of textbook style notes freely available can’t hurt.

I have been also heavily using Genius in class this semester to plot graphs and such.  Also putting in nice plots into the notes made it look even nicer (making me obsess over it more).  I’ve also had to add in all the functionality I needed for DE, such as slope field and vector plots.  There is still more Genius needs to do, so I guess I’ll have to spend a few more late nights on that.

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