sympy-latex-parser 1.9.0

Convert latex to sympy with ANTLR and support Matrix, Linear Algebra and CAS functions.

latex2sympy2

About

latex2sympy2 parses LaTeX math expressions and converts it into the equivalent SymPy form. The latex2sympy2 is adapted from augustt198/latex2sympy and purdue-tlt / latex2sympy.

This project is a part of a VS Code extension called Latex Sympy Calculator. It is designed for providing people writing in latex or markdown a ability to calculate something when writing math expression.

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

pip install latex2sympy2

Requirements: sympy and antlr4-python3-runtime packages.

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.