## Archive for the ‘Latex’ Category

xkcd is a popular webcomic that sometimes includes hand drawn graphs in a distinctive style. Here’s a typical example

In a recent Mathematica StackExchange question, someone asked how such graphs could be automatically produced in Mathematica and code was quickly whipped up by the community. Since then, various individuals and communities have developed code to do the same thing in a range of languages. Here’s the list of examples I’ve found so far

- xkcd style graphs in Mathematica. There is also a Wolfram blog post on this subject.
- xkcd style graphs in R. A follow up blog post at vistat.
- xkcd style graphs in LaTeX
- xkcd style graphs in Python using matplotlib
- xkcd style graphs in MATLAB. There is now some code on the File Exchange that does this with your own plots.
- xkcd style graphs in javascript using D3
- xkcd style graphs in Euler
- xkcd style graphs in Fortran

Any I’ve missed?

While on the train to work I came across a very interesting blog entry. Full LaTeX support (on device compilation and .dvi viewer) is now available on iPad courtesy of TeX Writer By FastIntelligence. Here is the blog post telling us the good news http://litchie.com/blog/?p=406

At the time of writing, the blog is down (**Update:** working again), possibly because of the click storm that my twitter announcement caused..especially after it was picked up by @TeXtip. So, here is the iTunes link http://itunes.apple.com/us/app/tex-writer/id552717222?mt=8

I haven’t tried this yet but it looks VERY interesting. If you get a chance to try it out, feel free to let me know how you get on in the comments section.

**Update 1: **This version of TeX writer(1.1) cannot output to .pdf. Only .dvi output is supported at the moment.

There are a lot of symbols in mathematics and I mean a LOT! Not content with the entire Greek alphabet, mathematicians have gone on to use symbols from other alphabets such as Hebrew. Once they had run out of alphabets they went on to invent hundreds of symbols themselves – a symbol for every occasion.

So, you are writing a paper in an esoteric (or maybe not so esoteric) area of mathematics and, naturally, you are writing it in Latex. Suddenly you think to yourself **‘What’s the LaTeX command for <insert weird and wonderful glyph here>’**

Searching in vain through list after list of LaTeX symbols you get to thinking **‘If only I could just draw the symbol and have the computer tell me what the LaTeX command is**‘.

Well now you can!

Detexify is a new project from Philipp Kühl (who had the initial idea) and Daniel Kirsch (who implemented it) and is essentially an exercise in machine learning. Sometimes it works perfectly (such as in the screenshot above) but other times it struggles a bit and you end up learning the commands for symbols you never even knew existed.

**Teach the system**

When it is struggling though, you can help it along. Eventually you will find the symbol you were looking for and you can click on it to tell the system **‘That squiggle I drew – this is what I meant’** thus helping to train it for future searchers.

Other times though, you cannot blame it for not finding the symbol you meant. For example I needed about 5 tries before I could get it to recognise my ham-fisted attempt at the lowercase zeta symbol. This says a lot more about my poor handwriting and mouse skills than it does about the quality of Texify though.

**Are you rubbish with the mouse? Use your finger on your mobile phone then!**

I found drawing even simple glyphs rather difficult with the mouse and soon found myself wishing that I could do it with my finger or a stylus so I was overjoyed to learn that Robin Baumgarten has released a version of Texify for Android mobile phones. The Android app works exactly like the web version and connects to the server in order to do the actual recognition.

Iphone users haven’t been left out though since Daniel has released an app for that himself.

This is a great project that Daniel is now developing for his diploma thesis and you and you can read more about its progress over at his blog.

From time to time I get sent someone’s thesis in the hope that I might be able to fix a Latex problem or two for them. I was recently looking at someone’s code on a newish Ubuntu 8.10 machine and when I tried to compile it I received the following error

! LaTeX Error: File `setspace.sty’ not found.

The Ubuntu package I needed was **texlive-latex-recommended** which I installed using

**sudo apt-get install ** **texlive-latex-recommended**

On trying to compile the code a second time I got the following error

! LaTeX Error: File `footmisc.sty’ not found.

which was fixed by

** sudo apt-get install texlive-latex-extra**

These packages don’t just install footmisc.sty and setspace.sty for you – they install a whole host of Latex packages as well.

Just as every walk (including random ones) must begin with a first step – every blog must have a first post. For my first post I thought I would mention the rather wonderful program that will allow me to use Latex to write equations on here – Mimetex.

The first solution that my web guru and I attempted to use was something called LatexRenderer but you need to have Latex installed on your web server to use it and for various reasons this was not possible for us. Mimetex, however, does not require Latex to be installed on your server so we gave that a go.

Once you have installed and activated the Mimetex plugin for wordpress all you need to do is put your Latex code between the two tags `[ tex][ /tex]`

(without spaces) and it will be automatically rendered as an image. This makes it very easy to write equations such as

The output from Mimetex is not quite as nice as that of LatexRenderer and it only supports a subset of Latex but the ease of installation more than makes up for this.