Older blog entries for vicious (starting at number 295)

Wrong dictionary

I must be using a wrong dictionary. Apparently Mubarak is not a dictator. I thought the whole, election-with-only-one-candidate trick didn’t work, but apparently … (sorry my mistake, in one of the elections others were allowed to run, but only he was allowed to win, big difference!)

Syndicated 2011-01-28 23:43:59 from The Spectre of Math

Vim, Evince and forward and backward LaTeX synctex search

I was finally fed up with not having forward and backward search in vim so I hacked up the python script that was in the gedit synctex package to do what I needed. The result is evince_vim_dbus.py. Copy it somewhere into your PATH (say ~/bin or /usr/local/bin). The first argument is EVINCE or GVIM. If it is EVINCE then it works just like the evince_dbus.py from the gedit synctex package. So to do forward search you add something like the following to your .vimrc file. This uses the LatexBox set of vim macros, which is pretty unobtrusive and kind of useful

function! LatexEvinceSearch()
execute "!cd " . LatexBox_GetTexRoot() . '; evince_vim_dbus.py EVINCE "`basename ' . LatexBox_GetOutputFile(). '`" ' . line('.') . ' "%:p"'
command! LatexEvinceSearch call LatexEvinceSearch()
au FileType tex map ls :silent LatexEvinceSearch

Make sure to compile your latex file with pdflatex –synctex=1 thefile. Now to jump to the right place in evince just type \ls in vim at the right spot. For vim-latex I assume something like the following would work though I have not tried so this may not actually work:

let g:Tex_ViewRule_pdf = 'evince_vim_dbus.py EVINCE'
let g:Tex_DefaultTargetFormat = 'pdf'
let g:Tex_CompileRule_pdf = 'pdflatex --synctex=1 -interaction=nonstopmode $*'

Now to do inverse search, what you want to do is open up evince with the .pdf file, open gvim with the file with something like: gvim –servername foo thefile.tex. The –servername argument will let us communicate with that instance of gvim. Now run

evince_vim_dbus.py GVIM foo thefile.pdf thefile.tex

This will keep running and will talk to evince and when you control-click somewhere the script will call the “foo” instance
of gvim and tell it to go to the right line. You have to kill this script once you are done. Yeah I know this is kind of ugly, but the way synctex is done in evince is kind of moronic. The idea is I think to make the thing as complicated as possible to satisfy someone’s CS design fetish rather than to make the thing simple and easily usable (such as doing it by calling evince with the right arguments and giving evince a command to execute) … but then no script like this would be needed.

I also have a modified whaw: whaw-jiri-0.1.2.tar.gz. When you run whaw –htile you will get a different cursor, you can left click bunch of windows and then right click and whaw will put the windows side by side. The standard whaw works as well, but the –htile is usable from scripts.

Finally to put it all together I have a script that runs everything for me called buildpdftexwatch (slightly modified version of the script from my homepage) which works as follows (by the way you need zsh installed for the script). You run buildpdftexwatch thefile where thefile doesn’t have any extension. The script will open thefile.tex in gvim and thefile.pdf in evince. If you have the modified whaw it will run it with –htile (otherwise it won’t run whaw). The script watches the .tex file and whenever you save in vim it will rerun pdflatex. (it also runs pdflatex in interactive mode when first invoked before it runs evince actually). It runs pdflatex in noninteractive mode afterwards so that it doesn’t hang. It will notify you of errors by barking (that is if you have ogg123 and the default gnome sound /usr/share/sounds/gnome/default/alerts/bark.ogg installed.

This setup is not perfect. Yeah I know I should probably rewrite the shell script to work in python so that the dbus thing can be done from the script itself. However, evince also sucks so I’d rather just use xpdf, but that does not yet have synctex support. At some point I may be enough annoyed with evince that I will hack xpdf to do syntex (and do it in the simple nondbusy way that will make it easy to work with all kinds of editors). For now … this works good enough.

Syndicated 2011-01-13 23:35:21 from The Spectre of Math

Assasinations, rhetoric, blame

So everyone is in the “who’s to blame” mode now. On one hand there is the “It was all Palin’s/Beck’s/Limbaugh’s fault” camp, and on the other side there is the “no it was just a deranged lunatic” camp. Can’t the truth be somewhere else. Why do we need a single direct cause for everything. Could it be that he was a lunatic, and could it be a combination of factors? I am sure that the political vitriol is definitely somewhat to blame. That doesn’t mean it is entirely to blame. But if I am insane and all the time on the radio/tv I hear hyperbolic rhetoric about hiltler this stalin this, communist that, reload, death panels, spilling blood, etc… then perhaps I will just be reinforced in thinking that I may be right about the government doing mind control rigging elections and taking away my rights and blood must be spilled. To a deranged person watching some TV shows it might seem as if the hyperbolic nonsense is actually completely mainstream. I mean most of the media seemed to sometimes believe some of the hyperbole was mainstream. During all the “death panels” talk, the media really did make it sound like most of the country thought that the government wants to kill our elderly.

My other point has to do with a czech saying about the “duck that was shot (who you can always hear).” If Palin thinks that the gunsights had absolutely positively nothing to do with what happened, than why did she take them down so quickly. If she topought about it, they would have been taken down right about the time the original controversy arose. She could say “I didn’t mean those to be gunsights, but if people are misrepresenting it that way, I’ll make it something else.” Instead she kept the graphic on in spite. That doesn’t mean that those gunsights did have any effect on the shooting. But it means that Palin knows that a connection can be made. If so many sane people made the connection to gunsights and shooting … why are we thinking that insane people won’t. That doesn’t mean Loughner did, but someone like him might.

Does it matter if Loughner was primarily motivated by right or left violent hyperbolic political rhetoric? If he was or wasn’t doesn’t mean there can’t be somebody else like that. What he proved is that there are people out there that are capable of an act like this. For whatever reason. If there are people that are capable of doing this, why are we egging them on?

Syndicated 2011-01-11 18:02:20 from The Spectre of Math

two down, two to go

Of the 4 things (papers) I am am working on, two are done! Yay! Well, done means one is posted to arXiv (though will appear only on thursday due to arXiv holiday schedule) and the other almost posted (still needs a few touchups). I think I can now relax for the rest of the holiday break (that is, after I finish those touchups :) .

Syndicated 2010-12-28 23:14:55 from The Spectre of Math

Thesis problem

So I’ve heard that a good thesis problem is one which will take you at least 5 years after you graduate to completely solve (or in the best case it is a problem which you will never solve completely, providing for a lifetime of work). Anyway, I’m getting close to “mostly solving” my original thesis problem: “Levi-flat hypersurfaces have Levi-flat singularities.” Of course it is only 3.5 years since I’ve finished my thesis so I’d better not completely solve it yet … That means I’ve been working on this sucker for over 5 years so far. That’s a reasonable problem. I think it’s got at least another few years in it before I’ve sucked it dry.

Then it amuses me when one of my students complains that a problem on the homework is hard because they’ve already
spent an hour on it and didn’t solve it yet.

Syndicated 2010-12-20 01:17:35 from The Spectre of Math

Estate tax

Just watching Morning Joe complaining about estate tax being immoral. In my opinion the estate tax should be as high as possible. In this respect I am a complete capitalist. I believe everyone should get the money they earn. Being born to the right parents is not “earning” money. I hope my parents burn through all their (now considerable amount) money before they die. Similarly, I don’t care if the government takes all my money when I die and leaves nothing for Maia. I hope she learns that she has to take care of herself.

Syndicated 2010-12-09 16:44:24 from The Spectre of Math

New chapter for the Diffy Qs book

I’ve written up a new short (14 pages) chapter for the Differential Equations textbook. I’ve put a draft on the web for my students as I’ll start covering it tomorrow (it’s only going to be 2 lectures, though the chapter should be usable for up to 3 lectures).

I suppose after Monday (after I finish lecturing on it), I’ll feel good enough about it to post a new version of the whole book with the chapter 7 in there.

I’ve caught quite a few typos and errors in the book this quarter, though I would say not any more than one can find in any first edition textbook. It seems that commercial publishers are very good at catching English grammar errors, but are terrible at catching mathematical mistakes. My book has probably more bad English than your average textbook. But I’m now feeling pretty good now about the mathematical content being correct.

A funky news is that apparently someone at Dartmouth College is planning to use the book for a course in their Winter term. I only heard from the bookstore that they asked if they can make copies of the book for the students, not actually from the instructor. I wonder how many courses have already used the book. I only know of a few …

Syndicated 2010-11-11 19:14:25 from The Spectre of Math

Voters speaking loud and clear

So after every election here, whichever party won starts saying nonsense like “voters spoke loud and clear.” That is simply nonsense. In every one of these elections that were claimed as overwhelming wins for one party the popular vote never goes beyond 45-55 or vice versa. The house vote was 52-44 this time around, last time it was 42-52. Let’s just assume 45-55. That’s like if you have some sort of club with 20 people, one person changed their mind. Hardly a “voters spoke loud and clear.”

Furthermore, in these midterms there were fewer people voting for the winning party than there were voting for the losing party in the last elections. So it’s entirely possible (though very unlikely) that not a single new person voted for republicans. That’s like in your club of 20 people where your side of an argument had 11-9 majority, suddenly only 15 people show up and you have
a 7-8 minority (actually that would be far far worse in terms of percentage of vote than what happened in the midterms). The members of the club would not have spoken loud and clear. Actually perhaps nobody actually changed their minds, it was just that there was a furniture sale somewhere that they had to go to.

From my experience with clubs related to any sort of activity, this is precisely what always happens, and why morons take over at some point. Actually come to think of it, that’s exactly what always happens in any sort of politics too.

The democrats are just as much to blame on this as the republicans. Whichever side wins always claims absolute mandate of the masses, even though nothing so drastic happened. This even happens when one side wins by 1 or 2 percent, which is really something that could have gone either way if the weather was bad. So if you win within such a small margin, you might as well flip a coin, you won on a technicality. So many democrats were angry about Gore and Bush. But that was all within margin of error. Maybe if the elections were held a week later it would have gone the other way. It was 50-50, there was no majority for either side. The same thing happened in ’04, except the roundoff error seemed to have gone in favor of Bush.

There should be a rule against such rhetoric unless your side wins 70-80 percent of the vote and the voter turnout is so large
that over 50 percent of eligible voters actually cast their ballot for you.

Syndicated 2010-11-11 18:01:08 from The Spectre of Math

Damn Murphy!

Murphy’s law strikes again. The moment you publish something (be it a textbook or a software), you find a bug. Yesterday I put on the web new versions of both my diffyqs notes and my real analysis notes. Already yesterday I found that when I posted the real anal notes on lulu, I forgot to update the book cover to state that I’m now at UCSD. OK, that’s a minor thing, who cares.

Today I was preparing for my diffy qs class and found an error in the notes. Actually I think I spotted this error in the spring when I taught at UIUC, but somehow forgot to fix it. So I find the first significant typo in the notes the day after posting new versions of the notes. And putting up new versions of the diffy qs notes is not as trivial as it may seem. It takes about 2 hours just to build the HTML version. This is because I have tex4ht do all math as images. Doing some of the math using CSS is faster, but then you get different font for some equations (as some are done using images and some using CSS).

If jsmath actually worked right, I would use that. But since I generally have a hard time making jsmath display things correctly on my own system, I assume that it doesn’t work right for a lot of people. Also jsmath seems to break for me for the pages as large as the notes. Mathml would be the perfect solution if it would work properly and consistently on all browsers. Right now for mathml and tex4ht you have to first decide on a browser to support, which beats the whole idea.

Browser developers are generally interested in floating 3d fish rather than actually useful stuff like supporting mathml properly. One of the reasons I am sticking to firefox is because the fact that they do support mathml reasonably, and have for a while, is an indication of sanity on the part of the developers.

Syndicated 2010-10-04 19:45:34 from The Spectre of Math

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