I converted a Python string into a formula with sympify as follows:
I converted the formula into MathML format with the mathml command.
from sympy import *
from sympy.printing.mathml import mathml
print(mathml(sympify("(2*x + 3*y + 1)*(4*x**2 - 6*x*y - 2*x + 9*y**2 - 3*y + 1)"),printer='presentation'))
As a result, the following code was output.
<mrow><mrow><mrow><mn>2</mn><mo>⁢</mo><mi>x</mi></mrow><mo>+</mo><mrow><mn>3</mn><mo>⁢</mo><mi>y</mi></mrow><mo>+</mo><mn>1</mn></mrow><mo>⁢</mo><mrow><mrow><mn>4</mn><mo>⁢</mo><msup><mi>x</mi><mn>2</mn></msup></mrow><mo>-</mo><mrow><mn>6</mn><mo>⁢</mo><mi>x</mi><mo>⁢</mo><mi>y</mi></mrow><mo>-</mo><mrow><mn>2</mn><mo>⁢</mo><mi>x</mi></mrow><mo>+</mo><mrow><mn>9</mn><mo>⁢</mo><msup><mi>y</mi><mn>2</mn></msup></mrow><mo>-</mo><mrow><mn>3</mn><mo>⁢</mo><mi>y</mi></mrow><mo>+</mo><mn>1</mn></mrow></mrow>
I embedded the code in HTML and tried it as follows.
test.html
<html>
<head>
<script async="" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.2/MathJax.js?config=TeX-MML-AM_CHTML"></script>
</head>
<body>
<math>
<mrow><mrow><mrow><mn>2</mn><mo>⁢</mo><mi>x</mi></mrow><mo>+</mo><mrow><mn>3</mn><mo>⁢</mo><mi>y</mi></mrow><mo>+</mo><mn>1</mn></mrow><mo>⁢</mo><mrow><mrow><mn>4</mn><mo>⁢</mo><msup><mi>x</mi><mn>2</mn></msup></mrow><mo>-</mo><mrow><mn>6</mn><mo>⁢</mo><mi>x</mi><mo>⁢</mo><mi>y</mi></mrow><mo>-</mo><mrow><mn>2</mn><mo>⁢</mo><mi>x</mi></mrow><mo>+</mo><mrow><mn>9</mn><mo>⁢</mo><msup><mi>y</mi><mn>2</mn></msup></mrow><mo>-</mo><mrow><mn>3</mn><mo>⁢</mo><mi>y</mi></mrow><mo>+</mo><mn>1</mn></mrow></mrow>
</math>
</body>
</html>
However, with this code, the output will be missing the Parentheses, as in the image below.
[![画像の説明をここに入力][1]][1]
I read the [source code of sympy.printing.mathml][2].
So I wondered what the _print_Interval method is used for.
Is this related to the problem of missing Parentheses in formulas?
This expression is an example. I want to convert even more complicated formulas properly.
I got the answer in the Japanese version of stackoverflow. https://ja.stackoverflow.com/q/55578/22541
Fixing [this][1] can solve the problem.
[Before]
for term in terms:
x = self._print(term)
mrow.appendChild(x)
[After]
for term in terms:
mrow.appendChild(self.parenthesize(term, PRECEDENCE['Mul']))