Wednesday, October 23, 2013

Summary of second meeting

The coffee served before the meeting comes from Italian food shop "Martina", one of the few places in Uppsala where one can buy premium coffee at reasonable price. A cheaper, but still decent, espresso is sold under the ICA brand, and Willis carries Najjar, excellent for Turkish coffee (stove-cooked), but too thinly ground for espresso machines. Illy coffee is found in ICA, and it is very good, but far overpriced. Quality of coffee is less affected by the quality of beans (except that arabica is nicer than robusta)  as by presence of defective beans and by speed with which it is roasted. Cheaper coffee means primitive sorting that leaves some rotten beans, and quick roasting (that increases volume per time unit and capital cost) which leads to loss of flavor.

We continued by discussing various aspects of math editing.

There are two ways to do TeX on portable devices, online (where you send your source for compilation on the server) and the good old local compiler.
The leading online TeX app for android is VerbTex, but almost everyone who has used it eventually gives up. TeXPortal (local compiler) seems to be the best solution so far.

TeXPortal is LaTeX for android devices. It comes with no TeX binaries at all, but installs them little by little based on what is needed for your source file. So, it may take an hour in the beginning looking at error messages - but it works at the end. TeXPortal uses TeTex, which is an older distribution superceded by TeXLive.
It also comes with no editor. Cyril suggested the 920 Text Editor. It is not classified as TeX (all apps that Cyril has seen under category Latex Editor are unusable, Emacs for Android is not as configurable, but vi affectionados can find something to their taste, like VIM Touch) , it is a programmer editor that hightlights syntax of a language, and you can choose TeX in the language option.

We also discussed TeX Live.
According to Wikipedia,
TeX Live is a free software distribution for the TeX typesetting system that includes major TeX-related programs, macro packages, and fonts. It is the replacement of its no-longer supported counterpart teTeX.
The good news is that, in addition to the above, TeX Live is now available for android, although the android port is still in an experimental phase. One needs to download and install the app, copy your TeXLive installation from Windows or Linux to  the /sdcard/texlive/ path, unpack  tl4a-2013-06-18.tar.xz, and use its content to replace the Windows/Linux binaries.

GmailTeX: There is also a way to write TeX in gmail - if you use Chrome as interface. Experiments by Cyril show that it does not work all the time, and when it does not, it shows the source TeX code instead. It can be installed via chrome://extensions and here is an example of what one can do
It works like this: once you press F8, Chrome translates TeX code into MathML. It is only the sender who needs to have  Gmail TeX installed. The recipient can be anyone, but whether they see the formula or TeX code depends on the mail client.

Lyx: an open source document processor based on LaTeX.
LyX (styled as \mathbf{L}\!{}_\mathbf{\displaystyle Y}\!\mathbf{X}) is an open source document processor based on top of the LaTeX typesetting system. Unlike most word processors, which follow the WYSIWYG ("what you see is what you get") paradigm, LyX has aWYSIWYM ("what you see is what you mean") approach, where what shows up on the screen is only an approximation of what will show up on the page.
A quick start guide for LyX. 
There are three shortcuts to remember.

  1. Control-M opens a math edit box where you write TeX. Some practice is required.
  2. Control-Shift-M does the same thing for display math.
  3. Control-R compiles and shows PDF.

A tip for people who do not like how the Math box behaves: write your TeX code as you want it, highlight it and press Control-M. This will show the graphics. You can always get it out of the Math box to edit.

The main non-common editing element of LyX is environment. Every portion of text in LyX is marked up with some environment modifier. It can be Theorem, or Proof, or Standard for the bread text. It can also be Itemize, or Author, or Abstract, or Frame if you prepare a Beamer presentation. Only those environments show in the menu that are supported by the Latex packages that your file invokes. This is set automatically by the file template, or manually in the preamble setting in the document menu.

LyX export to HTML makes beautiful MathJax files.
When you start a new file for anything other than report, exam or grant proposal, better use a ready template or import your earlier TeX file. All your personal TeX macros will be adopted (and you can define more in the Document menu). Note that while export to TeX works flawlessly, import from TeX usually does not make a pretty LyX file.


LaTeX in blogs etc. Wordpress has a long standing reputation for formulas in the text. Google has been experimenting with LaTeX in the most ambitious ways, but some of its experiments that it showed off previously are not seen anymore. Cyril retracts its reference to Blogspot. Firstly it was a mistake, and TeX code was accepted by Google Docs. not by Blogspot, and secondly, it was taken away in later versions of Google Drive. Google's online compiler, Latexlab , still exists, but is not recommended. For people who believe in virtues of online compilers, Sharelatex (former Scribtex) remains a better choice.

Last but not least, I'd like to give a hint on how to use sound on our ill-maintained computer system. We used to have sound but, according to the system administrators, there is no way to have it now. Why, I don't know. Other departments do have sound on their machines. However, here is a solution, not a perfect one, but a solution nevertheless:
  1. Press Control-F8
  2. Unselect "full screen"
  3. Minimize thinlink
  4. On the top left, click on Google Chrome
  5. There, you can have sound.
  6. For example, you can tune in to one of the best classical music radio stations in the world, Radio Swiss Classic. (Thanks to Salva Rodriguez-Lopez for this hint!)

Saturday, October 19, 2013

November meeting - planning

Theme: computers going modular.

While operating circuits (CPU, memory, graphics) tend to be more and more integrated, they are getting now into a small box, while all other components becoming more and more often detached. We will review:


  • SOC (systems-on-chip), which are now transiting from Android to Linux (Raspbery Pi, MK802 family and Cubox); We shall demonstrate a Linux server smaller than one crown coin.
  • IR versus BT portable keyboards; 
  • Removable storage (external hard drives, SD cards and flash memory);
  • Specialized network devices (NAS, printservers) are now more often a part of the router;
  • Smartphone as desktop: connecting smartphones with monitors, keyboards, mice, LAN and hard disks.

Other topics raised by members:

  • We will also start in earnest discussing SIP setups, something we did not get to taking up on the October meeting. 
  • Key bindings. What is worth to remember (Ctrl-Z, Alt-Tab, F5 and Ctrl-Alt-Del?).
  • Help! Experts in computer visualization  of functions and manifolds are badly needed. We did not plan it to be the subject of the club, but if anyone is an expert, can they please stand up?
  • Takis may tell how to make visualizations with maple and xfig.



Friday, October 11, 2013

Next meeting, Oct. 18, agenda

The next IT-club meeting will take place on Friday, October 18, 3:15, room Å74118. Theme of the meeting: new TeX environments.
Come few minutes earlier if you want to discuss setup on your personal laptop/tablet/phone. Coffee will be served. 


We plan some hands-on walkthrough for selected connectivity issues, such as

  • Eduroam configuration in different OS's;
  • Http proxy setup in browser settings;
  • Tips for setting up a SIP account; 
TeX environment topics:
For your own LyX install, all you need is to have a working Miktex or Texlive  and run the lyx installer (from LyX.org) or setup the LyX meta package for Linux.

Also, let's do some troubleshooting. For example, I have encountered the following problems:
  1. I don't know how to connect to the Internet from the Ubuntu partition on the laptop. (From the  Windows partition it works.)
  2. I frequently use http://libgen.org/ (and so do many others). However, downloading to a smartphone or to the ASUS tablet given to us by the department keeps failing. Solution: change on the frontpage of libgen.org the download type to "display  in browser". It won't display in browser on a mobile device of course, but a copy of the file with very descriptive name get.pdf will land in your Downloads directory. Apparently the "download type" appeals to the browser API, so if the browser does not have the invoked command, it gives a default response, which for a fancy command is "i donno" and for a simple command is the nearest similar action.