latex2Text

About

latex2Text parses LaTeX math expressions and converts it into the equivalent plain text. The latex2Text is adapted from OrangeX4/latex2sympy and purdue-tlt / latex2sympy.

It is designed to increase accessibility as current pdf readers are really bad at reading latex.

ANTLR is used to generate the parser.

Features

• Arithmetic: Add (+), Sub (-), Dot Mul (·), Cross Mul (×), Frac (/), Power (^), Abs (|x|), Sqrt (√), etc...
• Alphabet: a - z, A - Z, α - ω, Subscript (x_1), Accent Bar(ā), etc...
• Common Functions: gcd, lcm, floor, ceil, max, min, log, ln, exp, sin, cos, tan, csc, sec, cot, arcsin, sinh, arsinh, etc...
• Funcion Symbol: f(x), f(x-1,), g(x,y), etc...
• Calculous: Limit ($lim_{n\to\infty}$), Derivation ($\frac{d}{dx}(x^2+x)$), Integration ($\int xdx$), etc...
• Linear Algebra: Matrix, Determinant, Transpose, Inverse, Elementary Transformation, etc...
• Other: Binomial...

NOTICE: It will do some irreversible calculations when converting determinants, transposed matrixes and elementary transformations...

Installation

git clone maths-tts-org/latex2sympy

Requirements: sympy and antlr4-python3-runtime version 7.2 packages.

Pre-req

pip install antlr4-python3-runtime==4.7.2

Usage

Basic

In Python:

from latex2sympy2 import latex2sympy, latex2latex

tex = r"\frac{d}{dx}(x^{2}+x)"
# Or you can use '\mathrm{d}' to replace 'd'
latex2sympy(tex)
# => "Derivative(x**2 + x, x)"
latex2latex(tex)
# => "2 x + 1"

Examples

LaTeX	Converted SymPy	Calculated Latex
x^{3} $x^{3}$	x**3	x^{3} $x^{3}$
\frac{d}{dx} tx $\frac{d}{dx}tx$	Derivative(x*t, x)	t $t$
\sum_{i = 1}^{n} i $\sum_{i = 1}^{n} i$	Sum(i, (i, 1, n))	\frac{n \left(n + 1\right)}{2} $\frac{n \left(n + 1\right)}{2}$
\int_{a}^{b} \frac{dt}{t}	Integral(1/t, (t, a, b))	-\log{(a)} + \log{(b)} $-\log{(a)} + \log{(b)}$
`(2x^3 - x + z)	{x=3}` $(2x^3 - x + z)|{x=3}$	z + 51

If you want to read the math formula, you can click GitNotes.

Solve Equation

# Before
x + y = 1

# After
[ y = 1 - x, \  x = 1 - y]

Eval At

# Before
(x+2)|_{x=y+1}

# After
y + 3

Matrix

Identity matrix

tex = r"\bm{I}_3"
latex2sympy(tex)
# => "Matrix([[1, 0, 0], [0, 1, 0], [0, 0, 1]])"

Determinant

from latex2sympy2 import latex2sympy

tex = r"\begin{vmatrix} x & 0 & 0 \\ 0 & x & 0 \\ 0 & 0 & x \end{vmatrix}"
latex2sympy(tex)
# => "x^{3}"

Transpose

from latex2sympy2 import latex2sympy

tex = r"\begin{pmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{pmatrix}^T"
# Or you can use "\begin{pmatrix}1&2&3\\4&5&6\\7&8&9\end{pmatrix}'"
latex2sympy(tex)
# => "Matrix([[1, 4, 7], [2, 5, 8], [3, 6, 9]])"

Elementary Transformation

from latex2sympy2 import latex2sympy

matrix = r'''
    \begin{pmatrix}
        1 & 2 & 3 \\ 
        4 & 5 & 6 \\
        7 & 8 & 9 \\ 
    \end{pmatrix}
'''

# Scale the row with grammar "\xrightarrow{kr_n}"
tex = matrix + r'\xrightarrow{3r_1}'
latex2sympy(tex)
# => "Matrix([[3, 6, 9], [4, 5, 6], [7, 8, 9]])"

# Swap the cols with grammar "\xrightarrow{c_1<=>c_2}"
# Of course, you can use "\leftrightarrow" to replace "<=>" 
tex = matrix + r'\xrightarrow{c_1<=>c_2}'
latex2sympy(tex)
# => "Matrix([[2, 1, 3], [5, 4, 6], [8, 7, 9]])"

# Scale the second row and add it to the first row
# with grammar "\xrightarrow{r_1+kr_2}"
tex = matrix + r'\xrightarrow{r_1+kr_2}'
latex2sympy(tex)
# => "Matrix([[4*k + 1, 5*k + 2, 6*k + 3], [4, 5, 6], [7, 8, 9]])"

# You can compose the transform with comma ","
# and grammar "\xrightarrow[4r_3]{2r_1, 3r_2}"
# Remember the priority of "{}" is higher than "[]"
tex = matrix + r'\xrightarrow[4r_3]{2r_1, 3r_2}'
latex2sympy(tex)
# => "Matrix([[2, 4, 6], [12, 15, 18], [28, 32, 36]])"

Variances

from latex2sympy2 import latex2sympy, variances, var, set_variances

# Assign x a value of 1
latex2sympy(r"x = 1")

# Assign x a matrix symbol with dimension of n x m
latex2sympy(r"x \in \mathbb{R}^{n \times m}")

# Calculate x + y
latex2sympy(r"x + y")
# => "y + 1"

# Get all variances
print(variances)
# => "{x: 1}"

# Get variance of "x"
print(var["x"])
# => "1"

# Reset all variances
set_variances({})
latex2sympy(r"x + y")
# => "x + y"

Complex Number Support

from latex2sympy2 import set_real

set_real(False)

Contributing

If you want to add a new grammar, you can fork the code from OrangeX4/latex2sympy.

• To modify parser grammar, view the existing structure in PS.g4.
• To modify the action associated with each grammar, look into latex2sympy.py.

Contributors are welcome! Feel free to open a pull request or an issue.