LyX`@wisdom` FAQ

Written by Eran Tromer, last update 2004-02-16.
Thanks go to Shai Mor, Yuval Emek and, of course, the LyX developers team.

LyX is a GUI document processor which is closely related to LaTeX, both in semantics and implementation. It provides an attractive alternative to writing scientific documents directly in LaTeX, by providing an editable graphical rendering of the document and a graphical user interface for accessing various options and features. LyX can exports standard LaTeX files and uses LaTeX for producing its final output.

This document addresses some frequently asked questions about LyX, and particularly its use at the Faculty of Mathematics and Computer Science at the Weizmann Institute of Science.

1. Will this really save me from having to learn LaTeX?

No.

Eventually you'll know LaTeX, because the following situations will arise. First, you'll sometimes want to use LaTeX features (customizations and additional packages) which are not yet offered by LyX in a nice GUI way. Second, you'll sometimes need to write documents in cooperation with people who don't use LyX. In this light, you may wish to learn LaTeX now and forget about LyX (some good LaTeX editors are WinEdt, kile and good old emacs).

None the less, LyX is an excellent tool for getting starting with LaTeX, because you can use the GUI to achieve common tasks and then look at the exported LaTeX code to learn how to do it in raw LaTeX. Moreover, even experienced LaTeX users may find that using LyX is more efficient, due to the graphical display and manipulation tools (especially where mathematical formulas are concerned), and the knowledge of LaTeX makes LyX even more powerful.

Note that in regard to using LaTeX features not supported by LyX, the situation is not quite drastic as it sounds, since LyX allows incorporation of arbitrary LaTeX code (menu option Insert | TeX). This code is copied verbatim when the .lyx file is converted to .tex (see below about the conversion process).

2. How do I run LyX on the faculty computers?

Compile your own LyX in your Unix account on one of the new Linux hosts (eshkol, math01-lx to math10-lx, etc.):

Downloading the sourcecode from here,
Extracting the compile the sourcecode using "./configure --prefix=$HOME/local --with-frontend=qt; make; make install"
Run it using "~/local/bin/lyx".

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Download a Windows version of LyX (also from here) and somehow install and use it. You'll need MiKTeX and an X server installed on your PC, but you probably already have both.

3. How do I learn how to use it?

The Help menu inside the application contains extensive documentation. The tutorial is highly recommended.

4. I get an error about the DISPLAY variable.

Use telnet instead of use rlogin.
rlogin fails to transfer the DISPLAY environment variable which tells applications what is the current X server.

5. I wrote a test document but I can't view it and I can't export it to LaTeX.

There is an error in the user login scripts for faculty accounts opened prior to 2001-12-05.
To fix this, edit your ~/.cshrc file and replace the line
setenv TEXINPUTS .:$HOME/macros:/Tex/Macros
with the line
setenv TEXINPUTS .:$HOME/macros:/Tex/Macros:
(i.e., add a colon at the end). Alternatively, just 'unset TEXINPUTS '.
Afterwards telnet to verdi and invoke /usr/share/lyx/configure

6. Mathematical symbols don't show up properly.

LyX tries displays all mathematical symbols graphically, if it finds the appropriate font. If you're using Hummingbird Exceed then the default fonts don't include some symbol (e.g., \circ). You can solve this by running a font server and pointing Exceed to that server. If you need that, ask me how to do it.

But if your X server (i.e., the physical computer you're typing on) is a PC running Hummingbird Exceed on Windows NT, then many basic symbols will be invisible
(e.g., the sigma-like \sum symbol). There is a bug in Exceed. Upgrade to Windows 2000 or Windows XP. Technically: in all fonts, characters in column 192 and up are not rendered. I've contacted Hummingbird customer support about this (on 2001-12-06) and am awaiting their response.

7. LyX uses Alt for many keyboard shortcuts, but Exceed only lets me use the right Alt key. How can I use both?

This is configurable in the Hummingbird Exceed XConfig utility, accessible via the Start menu.

I highly recommend the use of keyboard shortcuts whenever possible. Note that when you use the Math Panel to insert a mathematical symbol, its keyboard shortcut shows in the buttom of the screen. More on this in the question about creating math equations, below.

8. What precisely is the relation between LyX and LaTeX/DVI/PostScript?

Here's the file conversion pipeline:

file.lyx is LyX's own format -- this is the only file you edit directly.
file.tex is in the standard LaTeX format. It's created by LyX from file.lyx.
file.dvi is in the semi-graphical DVI format which you can view using xdvi. It's created from file.tex by "latex file.tex".
file.ps is PostScript file created from file.dvi by "dvips file.ps -o".

This pipeline is unidirectional (actually it's possible to convert simple LaTeX documents to the LyX format using reLyX, but this often fails). LyX can directly export or view (where relevant) any file in this pipeline. In particular:

Alt-F E L writes the LaTeX file to disk.
Alt-F E T writes the PostScript file to disk.
Ctrl-D creates and views the DVI file
Shift-Ctrl-D (or Alt-V U D) refreshes the DVI file after you've used Ctrl-D. xdvi will reread it when you give it focus.
Ctrl-T creates and views the PostScript file.

9. How do I create math equations?

The full details are in the documentation, but here are the important bits. Math stuff is entered in a dedicated mode called "Mathed" (math editor). You enter Mathed using Ctrl-M . Once in Mathed, here are some common actions:

Pressing Space exits the current scope (subscript, root, or even the whole equation). You'll need to pay attention to which scope you're in -- this can be confusing at first, since the visual inducation is sometimes subtle.
The menu option Edit | Math | Math Panel (accassible via Alt-I H L) opens the Math Panel dialog, where you can choose many symbols and components of equations.
The majority of buttons in Math Panel have keyboard shortcuts. To discover them easily, choose an option in the Math Panel -- the shortcut (if any) appears at the bottom line of the screen. Using keyboard shortcuts is much faster than using Math Panel.
You can also type many common LaTeX commands, such as: \sum \sqrt \cdot \beta \rightarrow \underbrace \oplus. As soon as you press Space to indicate the command is done, LyX converts it to a nicely rendered representation. If LyX is not familiar with this command, it's left as a red string that's passed verbatim for pressing by LaTeX.
Pressing "_" (underline) creates a subscript (use Space to end).
Pressing "^" (hat) creates a superscript (use Space to end).
"Alt-M (", " Alt-M [", "Alt-M < " and "Alt-M {" create parentheses (of the various kinds) which change their height automatically according to their content.
When already in Mathed, Ctrl-M invokes "math text mode", which lets you write normal text (i.e., upright and with normal letter spacing) inside formulas.
Alt-M D makes the equation "displayed" ($$ vs. $ in LaTeX)-- it's centered horizontally and certain elements are typeset in a less cramped style. When editing a displayed equation, Ctrl-Enter turns it into an equation array with multiple lines ( Ctrl-Enter adds a new line) and 3 columns (right-aligned, center-aligned, left-aligned).

10. How do I insert claims, lemmas, proofs, etc. in a nice way?

In the Layout menu, choose Document and change Class from "Article " to "Article (AMS)". Additional mathematics-related environments are now available, and you can mark paragraphs as lemmas etc.

11. How do I created nested environments, such as nested lists?

Alt-P Rightarrow increases the nesting level while Alt-P Leftarrow decreases it. You'll also find these useful: Alt-P Space opens the dropdown list of environments, while Alt-P S chooses the Standard environment (i.e, normal text).

12. How do I print from LyX when I run it on the faculty's Linux servers?

See the list of available Unix/Linux printers here.

Alternatively, export your document to PostScript (using Alt-F E T) and then print file.ps file from another machine (silver and winter work well, and so do Windows boxes if a printer is configured -- see next question).

13. What was that about printing from Windows? How do I access the file?

Surely not using FTP -- that's very inconvenient. You can access your Unix home directory as a normal Windows share, namely "\\silver\username". However, you'll first need to ask Yorram Kalef (Ziskind room 21) to create a "Samba account" for you.

For any suggestions or additional questions, please mail me.

LyX@wisdom FAQ