Latexify examples

This notebook provides several examples to use latexify.
Author

Benedict Thekkel

See also the official documentation for more details.

If you have any questions, please ask it in the issue tracker.

Install latexify

Import latexify into your code

import math  # Optional
import numpy as np  # Optional
import latexify

latexify.__version__
'0.4.2'

Examples

@latexify.function
def solve(a, b, c):
  return (-b + math.sqrt(b**2 - 4*a*c)) / (2*a)

print(solve(1, 4, 3))  # Invoking the function works as expected.
print(solve)  # Printing the function shows the underlying LaTeX source.
solve  # Displays the expression.

# Writes the underlying LaTeX source into a file.
with open("compiled.tex", "w") as fp:
  print(solve, file=fp)
-1.0
\mathrm{solve}(a, b, c) = \frac{-b + \sqrt{ b^{2} - 4 a c }}{2 a}
# latexify.expression works similarly, but does not output the signature.
@latexify.expression
def solve(a, b, c):
  return (-b + math.sqrt(b**2 - 4*a*c)) / (2*a)

solve

\[ \displaystyle \frac{-b + \sqrt{ b^{2} - 4 a c }}{2 a} \]

# latexify.get_latex obtains the underlying LaTeX expression directly.
def solve(a, b, c):
  return (-b + math.sqrt(b**2 - 4*a*c)) / (2*a)

latexify.get_latex(solve)
'\\mathrm{solve}(a, b, c) = \\frac{-b + \\sqrt{ b^{2} - 4 a c }}{2 a}'
@latexify.function
def sinc(x):
  if x == 0:
    return 1
  else:
    return math.sin(x) / x

sinc

\[ \displaystyle \mathrm{sinc}(x) = \left\{ \begin{array}{ll} 1, & \mathrm{if} \ x = 0 \\ \frac{\sin x}{x}, & \mathrm{otherwise} \end{array} \right. \]

# Elif or nested else-if are unrolled.
@latexify.function
def fib(x):
  if x == 0:
    return 0
  elif x == 1:
    return 1
  else:
    return fib(x-1) + fib(x-2)

fib

\[ \displaystyle \mathrm{fib}(x) = \left\{ \begin{array}{ll} 0, & \mathrm{if} \ x = 0 \\ 1, & \mathrm{if} \ x = 1 \\ \mathrm{fib} \mathopen{}\left( x - 1 \mathclose{}\right) + \mathrm{fib} \mathopen{}\left( x - 2 \mathclose{}\right), & \mathrm{otherwise} \end{array} \right. \]

# Some math symbols are converted automatically.
@latexify.function(use_math_symbols=True)
def greek(alpha, beta, gamma, Omega):
  return alpha * beta + math.gamma(gamma) + Omega

greek

\[ \displaystyle \mathrm{greek}(\alpha, \beta, \gamma, \Omega) = \alpha \beta + \Gamma \mathopen{}\left( \gamma \mathclose{}\right) + \Omega \]

# Function names, arguments, variables can be replaced.
identifiers = {
    "my_function": "f",
    "my_inner_function": "g",
    "my_argument": "x",
}

@latexify.function(identifiers=identifiers)
def my_function(my_argument):
    return my_inner_function(my_argument)

my_function

\[ \displaystyle f(x) = g \mathopen{}\left( x \mathclose{}\right) \]

# Assignments can be reduced into one expression.
@latexify.function(reduce_assignments=True)
def f(a, b, c):
    discriminant = b**2 - 4 * a * c
    numerator = -b + math.sqrt(discriminant)
    denominator = 2 * a
    return numerator / denominator

f

\[ \displaystyle f(a, b, c) = \frac{-b + \sqrt{ b^{2} - 4 a c }}{2 a} \]

# Matrix support.
@latexify.function(reduce_assignments=True, use_math_symbols=True)
def transform(x, y, a, b, theta, s, t):
  cos_t = math.cos(theta)
  sin_t = math.sin(theta)
  scale = np.array([[a, 0, 0], [0, b, 0], [0, 0, 1]])
  rotate = np.array([[cos_t, -sin_t, 0], [sin_t, cos_t, 0], [0, 0, 1]])
  move = np.array([[1, 0, s], [0, 1, t], [0, 0, 1]])
  return move @ rotate @ scale @ np.array([[x], [y], [1]])

transform

\[ \displaystyle \mathrm{transform}(x, y, a, b, \theta, s, t) = \begin{bmatrix} 1 & 0 & s \\ 0 & 1 & t \\ 0 & 0 & 1 \end{bmatrix} \cdot \begin{bmatrix} \cos \theta & -\sin \theta & 0 \\ \sin \theta & \cos \theta & 0 \\ 0 & 0 & 1 \end{bmatrix} \cdot \begin{bmatrix} a & 0 & 0 \\ 0 & b & 0 \\ 0 & 0 & 1 \end{bmatrix} \cdot \begin{bmatrix} x \\ y \\ 1 \end{bmatrix} \]

# latexify.algorithmic generates an algorithmic environment instead of an equation.
@latexify.algorithmic
def fib(x):
  if x == 0:
    return 0
  elif x == 1:
    return 1
  else:
    return fib(x-1) + fib(x-2)

fib
$ \[\begin{array}{l} \mathbf{function} \ \mathrm{fib}(x) \\ \hspace{1em} \mathbf{if} \ x = 0 \\ \hspace{2em} \mathbf{return} \ 0 \\ \hspace{1em} \mathbf{else} \\ \hspace{2em} \mathbf{if} \ x = 1 \\ \hspace{3em} \mathbf{return} \ 1 \\ \hspace{2em} \mathbf{else} \\ \hspace{3em} \mathbf{return} \ \mathrm{fib} \mathopen{}\left( x - 1 \mathclose{}\right) + \mathrm{fib} \mathopen{}\left( x - 2 \mathclose{}\right) \\ \hspace{2em} \mathbf{end \ if} \\ \hspace{1em} \mathbf{end \ if} \\ \mathbf{end \ function} \end{array}\]

$

# Another example: latexify.algorithmic supports usual control flows.
@latexify.algorithmic
def collatz(x):
  n = 0
  while x > 1:
    n = n + 1
    if x % 2 == 0:
      x = x // 2
    else:
      x = 3 * x + 1
  return n

collatz
$ \[\begin{array}{l} \mathbf{function} \ \mathrm{collatz}(x) \\ \hspace{1em} n \gets 0 \\ \hspace{1em} \mathbf{while} \ x > 1 \\ \hspace{2em} n \gets n + 1 \\ \hspace{2em} \mathbf{if} \ x \mathbin{\%} 2 = 0 \\ \hspace{3em} x \gets \left\lfloor\frac{x}{2}\right\rfloor \\ \hspace{2em} \mathbf{else} \\ \hspace{3em} x \gets 3 x + 1 \\ \hspace{2em} \mathbf{end \ if} \\ \hspace{1em} \mathbf{end \ while} \\ \hspace{1em} \mathbf{return} \ n \\ \mathbf{end \ function} \end{array}\]

$

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