## [LaTeX] Write partial differential equation (Ex. dQ/dt=ds/dt) with partial derivative signs

\documentclass{article}
\begin{document}

$$\frac{\partial Q}{\partial t} = \frac{\partial s}{\partial t}$$

\end{document}

$$\frac{\partial h}{\partial t} + \frac{\partial uh}{\partial x} + \frac{\partial vh}{\partial y} = 0$$

• equation with numbering
$$\frac{\partial h}{\partial t} + \frac{\partial uh}{\partial x} + \frac{\partial vh}{\partial y} = 0$$

• equation with name no numbering
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\newcommand{\eqname}[1]{\tag*{#1}}% Tag equation with name

\begin{document}

$$\frac{\partial h}{\partial t} + \frac{\partial uh}{\partial x} + \frac{\partial vh}{\partial y} = 0 \eqname{Continuity Equation} \$$

\end{document}

• equation with both name and numbering
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\newcommand{\eqname}[1]{\tag*{#1}}% Tag equation with name

\begin{document}

\begin{align}
\frac{\partial h}{\partial t} + \frac{\partial uh}{\partial x} + \frac{\partial vh}{\partial y} = 0 \\ \eqname{Continuity Equation} \
\end{align}

\end{document}

• equation with both name and numbering and ref equation in text body
\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\newcommand{\eqname}[1]{\tag*{#1}}% Tag equation with name
\begin{document}

\begin{align}
f(x) &= a \\ \eqname{Constant} \ g(x) &= ax \\ \eqname{Linear} \ h(x) &= ax^2+bx+c \label{abc} \\ \eqname{Quadratic}
\end{align}

See~\eqref{abc}.
\end{document}

## [LaTeX] Add TOC in LaTeX

It is always convenient and helpful to have a (clickable) TOC while we are preparing for our publications. It will give us a big picture of our work.

Put the piece of code I provided below immediately before your \section{Introduction} in your .tex file, you will have a clickable TOC in your tex created pdf! Happy Writing:)!

\newpage

\thispagestyle{empty}
\setcounter{tocdepth}{4}
\normalsize
\tableofcontents
\normalsize
\newpage

%\pagestyle{fancy}

\setcounter{page}{1}
\setcounter{section}{0}
%\cfoot{\small \sffamily \thepage}
\pagenumbering{arabic}

## Usage tips for iPhone or iPad or iPod touch

This post provides some useful iPhone tips.

• How to create apps folders on iPhone or iPad
1. Go to your Home screen.
2. Touch and hold your finger down on the app you want to create a folder until all apps begin to jiggle.
3. Keep holding your finger down on the app and drag it on top of another app you want in the same folder.
• How to Rearrange Apps and Folders on iPhone

Tap on an app and hold your finger on it until the icons start shaking. When the appicons are shaking, just drag and drop the app icon to a new location. You canrearrange them in whatever order you want (icons have to swap places on the screen; they can’t have empty space between them.)

• How to rename folders on your iPhone

iPhone assigns a name it thinks is appropriate by default, such as Utilities, Productivity, Lifestyle, or Entertainment, based on the kinds of apps you put in the folder, but you can change the name with these steps:

1. Press and hold an app on the Home screen.

2. Tap the wiggling folder whose name you want to edit.

3. Tap the circled X on the right of the field where the name is written.

The field is erased. A cursor appears at the beginning of the field and the keyboard opens.

4. Tap out the name you wish to give this folder.

5. Tap the Done key on the bottom right of the keyboard.

6. Tap outside the folder to close it.

The buttons are still wiggling.

7. Tap the Home button to save the renamed folder.

Notes: If your apps folder has a badge on the upper right corner, the number on the badge is a cumulative number of items that need attending to, such as unread messages, app updates, or information updates

•  How to take a screenshot on your iPhone, iPad, and iPod touch
You can capture the screen on your iOS device using the Sleep/Wake and Home buttons.
1. Press and hold the Sleep/Wake button on the top or side of your device.
2. Immediately press and release the Home button.
3. To find your screenshot, go to the Photos app > Albums and tap Camera Roll.

See links below for more tips:

## [LaTeX] Add footnote and make url in footnote clickable

Use the package hyperref and call the url by \url{https://someplace.org}

\documentclass{report}

\usepackage{hyperref}

\begin{document}

The paragraph\footnote{this text will appear at the footnote area, leave it blank if no text is needed \url{https://someplace.org}}.

\end{document}

## [LaTeX] Renaming the bibliography section title using BibTeX

Sometimes we need to rename default “References” to “Recent publications”, or what ever you would like to change it to.

This depends on the document class. The command may be:

\renewcommand\refname{Recent publications}

OR

\renewcommand\bibname{Recent publications}

(Add the command to your preamble. Sometimes if it does not work, try to add the new definition after \begin{document}. )

## [LaTeX] Include a reference in the bibliography without citing it in the text

Sometimes when we are writing documents  (e.g., for some applications), where it may require a list of recent publications – in this case, we need to list the references without citing it in the text body. The solution is:

Use \nocite{keyname} for a single input in the references without marking it in the document. To mark any key in the .bib file use \nocite{*}

write \nocite{*} for all entries in the bib data file or \nocite{key} for a single one, which is not cited in the text. Place these commands anywhere in your text body. I prefer the place before printing the bib.

For example:

%myrefbib.bib
@misc{abc,
author = "NAME",
date = "YEAR",
howpublished = "ACM Digital"
}
%example.tex

\documentclass{article}

\begin{document}

\nocite{abc}

\bibliographystyle{alpha}
\bibliography{myrefbib}

\end{document}

## Online LaTeX Editors: ShareLaTeX vs Overleaf (formerly WriteLaTeX)

Now ShareLaTeX and Overleaf are teamed up, so we do not need to worry about choosing which. We just need to use the merged online LaTeX Editor here: Online LaTeX Editor Overleaf.

************

ShareLaTeX is an online LaTeX editor that allows real-time collaboration and online compiling of projects to PDF format.  Overleaf (formerly called WriteLaTeX) is another popular online LaTeX editor that allows collaborative LaTex editing. See the post Comparison: ShareLaTeX vs Overleaf (formerly WriteLaTeX) for more details about the comparison.

Some main points from the comparison:

ShareLaTex:

• word count
• compiles faster
• autocomplete is more robust: it works with package and custom commands
• It doesn’t spawn multiple browser windows/tabs like Overleaf

Overleaf:

• many templates for all kinds of documents and scientific journals
• support for collaborative editing
• word count is supported now
• the free version supports Git. It is possible to clone your project to your computer, work on it offline, commit your changes, pull new changes, etc.
• you can download your bibliography directly from Zotero (so you can just click refresh, rather than export a bib file from your computer then upload it).
• autocompile and better editor/preview position sync.

Main differences:

• about the use of BibTeX:
Overleaf gives you popup access to a search windows when typing \citep{}, making easy to find the key you want to use; while ShareLaTeX does nothing.
• for privacy some users probably preferred ShareLaTeX because the documents are private. In free Overleaf, whoever has the document url can edit, even though now you can get Read only-links for Overleaf projects.
• free versions comparison: Overleaf Plans and Pricing vs ShareLaTex Plans & Pricing
• free version of ShareLaTeX:

My conclusions:

I have tried both, and I personally prefer ShareLaTeXShareLaTeX is better than Overleaf because of the slightly better feature set.

In ShareLaTeX, even in free version, your projects are private. But in Overleaf you need to use Pro version to get this benefit.

ShareLaTeX is better for users with LaTeX experience. Whereas Overleaf is good for users who have few LaTeX experience, because it supports both Rich text and LaTeX.

I have the similar conclusion as what this post describes: ShareLaTeX and latexdiff are two LaTeX gems. See my post for the usage of latexdiff.

(Thanks Guido for recommending ShareLaTeX and Overleaf to me.)