How to write LaTeX in IPython Notebook?

IPython notebook uses MathJax to render LaTeX inside html/markdown. Just put your LaTeX math inside $$.

$$c = \sqrt{a^2 + b^2}$$

https://latex.codecogs.com/png.latex?c=%5csqrt%7ba%5e2%2bb%5e2%7d

Or you can display LaTeX / Math output from Python, as seen towards the end of the notebook tour:

from IPython.display import display, Math, Latex
display(Math(r'F(k) = \int_{-\infty}^{\infty} f(x) e^{2\pi i k} dx'))

https://i.stack.imgur.com/nqivH.png

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This came up in a search I was just doing, found a better solution with some more searching, IPython notebooks now have a %%latex magic that makes the whole cell Latex without the $$ wrapper for each line.

Refer notebook tour for Rich Display System

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LaTeX References:

Udacity's Blog has the Best LaTeX Primer I've seen: It clearly shows how to use LaTeX commands in easy to read, and easy to remember manner !! Highly recommended.

This Link has Excellent Examples showing both the code, and the rendered result !
You can use this site to quickly learn how to write LaTeX by example.

And, here is a quick Reference for LaTeX commands/symbols.

To Summarize: various ways to indicate LaTeX in Jupyter/IPython:

Examples for Markdown Cells:

inline, wrap in: $

The equation used depends on whether the the value of  
$V​max​​$ is R, G, or B.  

block, wrap in: $$

$$H←  ​​​​​0 ​+​ \frac{​​30(G−B)​​}{Vmax−Vmin}  ​​, if V​max​​ = R$$

block, wrap in: \begin{equation} and \end{equation}

\begin{equation}
H← ​​​60 ​+​ \frac{​​30(B−R)​​}{Vmax−Vmin}  ​​, if V​max​​ = G
\end{equation}

block, wrap in: \begin{align} and \end{align}

\begin{align}
H←120 ​+​ \frac{​​30(R−G)​​}{Vmax−Vmin}  ​​, if V​max​​ = B
\end{align}

Examples for Code Cells:

LaTex Cell: %%latex magic command turns the entire cell into a LaTeX Cell

%%latex
\begin{align}
\nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \\
\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \\
\nabla \cdot \vec{\mathbf{B}} & = 0
\end{align}

Math object to pass in a raw LaTeX string:

from IPython.display import Math
Math(r'F(k) = \int_{-\infty}^{\infty} f(x) e^{2\pi i k} dx')

Latex class. Note: you have to include the delimiters yourself. This allows you to use other LaTeX modes such as eqnarray:

from IPython.display import Latex
Latex(r"""\begin{eqnarray}
\nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} & = \frac{4\pi}{c}\vec{\mathbf{j}} \\
\nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \\
\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \\
\nabla \cdot \vec{\mathbf{B}} & = 0 
\end{eqnarray}""")

Docs for Raw Cells:

(sorry, no example here, just the docs)

Raw cells Raw cells provide a place in which you can write output directly. Raw cells are not evaluated by the notebook. When passed through nbconvert, raw cells arrive in the destination format unmodified. For example, this allows you to type full LaTeX into a raw cell, which will only be rendered by LaTeX after conversion by nbconvert.

Additional Documentation:

For Markdown Cells, as quoted from Jupyter Notebook docs:

Within Markdown cells, you can also include mathematics in a straightforward way, using standard LaTeX notation: $...$ for inline mathematics and $$...$$ for displayed mathematics. When the Markdown cell is executed, the LaTeX portions are automatically rendered in the HTML output as equations with high quality typography. This is made possible by MathJax, which supports a large subset of LaTeX functionality Standard mathematics environments defined by LaTeX and AMS-LaTeX (the amsmath package) also work, such as \begin{equation}...\end{equation}, and \begin{align}...\end{align}. New LaTeX macros may be defined using standard methods, such as \newcommand, by placing them anywhere between math delimiters in a Markdown cell. These definitions are then available throughout the rest of the IPython session.

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Use $$ if you want your math to appear in a single line, e.g.,

$$a = b + c$$ (line break after the equation)

If you don't need a line break after the math, use single dollar sign $, e.g.,

$a = b + c$   (no line break after the equation)

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You can choose a cell to be markdown, then write latex code which gets interpreted by mathjax, as one of the responders say above.

Alternatively, Latex section of the iPython notebook tutorial explains this well.

You can either do:

from IPython.display import Latex
Latex(r"""\begin{eqnarray}
\nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} & = \frac{4\pi}{c}\vec{\mathbf{j}} \\
\nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \\
\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \\
\nabla \cdot \vec{\mathbf{B}} & = 0 
\end{eqnarray}""")

or do this:

%%latex
\begin{align}
\nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} & = \frac{4\pi}{c}\vec{\mathbf{j}} \\
\nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \\
\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \\
\nabla \cdot \vec{\mathbf{B}} & = 0
\end{align}

More info found in this link

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I developed prettyPy, which offers a nice way to print equation. Unfortunately, it's not performant and needs testing.

Example:

https://i.stack.imgur.com/7LNrv.png

Granted, sympy is a great alternative and although prettyPy doesn't allow for evaluating expressions, variable initialization is not required.

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Since, I was not able to use all the latex commands in Code even after using the %%latex keyword or the $..$ limiter, I installed the nbextensions through which I could use the latex commands in Markdown. After following the instructions here: https://github.com/ipython-contrib/IPython-notebook-extensions/blob/master/README.md and then restarting the Jupyter and then localhost:8888/nbextensions and then activating "Latex Environment for Jupyter", I could run many Latex commands. Examples are here: https://rawgit.com/jfbercher/latex_envs/master/doc/latex_env_doc.html

\section{First section}
\textbf{Hello}
$
\begin{equation} 
c = \sqrt{a^2 + b^2}
\end{equation}
$
\begin{itemize}
\item First item
\item Second item
\end{itemize}
\textbf{World}

As you see, I am still unable to use usepackage. But maybe it will be improved in the future.

https://i.stack.imgur.com/AFdQ7.png

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I wrote how to write LaTeX in Jupyter Notebook in this article.

You need to enclose them in dollar($) signs.

To align to the left use a single dollar($) sign.

$P(A)=\frac{n(A)}{n(U)}$

To align to the center use double dollar($$) signs.

$$P(A)=\frac{n(A)}{n(U)}$$

Use \limits for \lim, \sum and \int to add limits to the top and the bottom of each sign.

Use a backslash to escape LaTeX special words such as Math symbols, Latin words, text, etc.

https://i.stack.imgur.com/T6NkD.png

Try this one.

$$\overline{x}=\frac{\sum \limits _{i=1} ^k f_i x_i}{n} \text{, where } n=\sum \limits _{i=1} ^k f_i  $$

Matrices

https://i.stack.imgur.com/UMYVz.png

Piecewise functions

$$
\begin{align}
\text{Probability density function:}\\
\begin{cases}
\frac{1}{b-a}&\text{for $x\in[a,b]$}\\
0&\text{otherwise}\\
\end{cases}
\\
\text{Cumulative distribution function:}\\
\begin{cases}
0&\text{for $x<a$}\\
\frac{x-a}{b-a}&\text{for $x\in[a,b)$}\\
1&\text{for $x\ge b$}\\
\end{cases}
\end{align}
$$

The above code will create this.

https://i.stack.imgur.com/PRwil.png

If you want to know how to add numbering to equations and align equations, please read this article for details.

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The answer given by minrk (included for completeness) is good, but there is another way that I like even more.

You can also render an entire cell as LaTeX by typing %%latex as the first line in a text cell. This is usefull if you

want more control,

want more than just a math environment,

or if you are going to write a lot of math in one cell.

minrk's answer:

IPython notebook uses MathJax to render LaTeX inside html/markdown. Just put your LaTeX math inside $$. $$c = \sqrt{a^2 + b^2}$$ Or you can display LaTeX / Math output from Python, as seen towards the end of the notebook tour: from IPython.display import display, Math, Latex display(Math(r'F(k) = \int_{-\infty}^{\infty} f(x) e^{2\pi i k} dx'))

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If your main objective is doing math, SymPy provides an excellent approach to functional latex expressions that look great.

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Using LaTeX syntax directly in a Markdown cell works for me. I'm using Jypiter 4.4.0.

I don't have to use %%latex magic command, I insist, simply a markdown cell:

\begin{align}
\nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} & = \frac{4\pi}{c}\vec{\mathbf{j}} \\
\nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \\
\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \\
\nabla \cdot \vec{\mathbf{B}} & = 0
\end{align}

Renders to:

https://i.stack.imgur.com/QeOTB.png

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I came across this problem some day using colab. And I find the most painless way is just running this code before printing. Everything works like charm then.

from IPython.display import Math, HTML

def load_mathjax_in_cell_output():
  display(HTML("<script src='https://www.gstatic.com/external_hosted/"
               "mathjax/latest/MathJax.js?config=default'></script>"))
get_ipython().events.register('pre_run_cell', load_mathjax_in_cell_output)
import sympy as sp
sp.init_printing()

The result looks like this:

https://i.stack.imgur.com/Qe3pO.png

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I am using Jupyter Notebooks. I had to write

%%latex
$sin(x)/x$

to get a LaTex font.

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Yet another solution for when you want to have control over the document preamble. Write a whole document, send it to system latex, convert the pdf to png, use IPython.display to load and display.

import tempfile
import os.path
import subprocess
from IPython.display import Image, display

with tempfile.TemporaryDirectory(prefix="texinpy_") as tmpdir:
    path = os.path.join(tmpdir, "document.tex")
    with open(path, 'w') as fp:
        fp.write(r"""
        \documentclass[12pt]{standalone}
        \begin{document}
        \LaTeX{}
        \end{document}
        """)
    subprocess.run(["lualatex", path], cwd=tmpdir)
    subprocess.run(["pdftocairo", "-singlefile", "-transp", "-r", "100", "-png", "document.pdf", "document"], cwd=tmpdir)
    im = Image(filename=os.path.join(tmpdir, "document.png"))
    display(im)

https://i.stack.imgur.com/21BdL.png

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If you want to display a LaTeX equation from a notebook code cell you can create a simple wrapper class that makes use of the Jupyter notebooks rich display representation. This class should have a _repr_latex_ method (note this single underscore at the start and end rather than the double underscores of other special methods) that outputs the LaTeX string. E.g.:

class LaTeXEquation:
    def __init__(self, eqntext):
        self.eqntext = eqntext

    def __repr__(self):
        return repr(self.eqntext)

    def _repr_latex_(self):
        """
        Special method for rich display of LaTeX formula.
        """

        # add $'s at start and end if not present
        if self.eqntext.strip()[0] != "$" and self.eqntext.strip()[-1] != "$":
            return "$" + self.eqntext + "$"
        else:
            return self.eqntext

myeqn = "x = y^2"

Then in a code cell, if you do, e.g.,

LaTeXEquation(myeqn)

it will show the formatted equation.

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