A computer algebra system written in pure Python http://sympy.org/ . To get started to with contributing https://github.com/sympy/sympy/wiki/Introduction-to-contributing
According to the docs it depends on the expression to be simplified. You might need to provide some assumptions for your symbols and in general avoid simplify() if cost is a concern.
Hi all,
I'm trying to use SymPy's parse_latex
function to parse mixed-fractions. But the issue that's happening is, the tree representation of mixed-fraction is same as if the integer part of mixed fraction were getting multiplied with fractional part of the mixed fraction.
Minimal code example:
>>> from sympy.parsing.latex import parse_latex
>>> from sympy import srepr
>>> e1 = "1 \\frac{1}{3}"
>>> e2 = "1 \\times \\frac{1}{3}"
>>> expr1 = parse_latex(e1)
>>> expr2 = parse_latex(e2)
>>> print(srepr(expr1))
Mul(Integer(1), Pow(Integer(3), Integer(-1)))
>>> print(srepr(expr2))
Mul(Integer(1), Pow(Integer(3), Integer(-1)))
>>> srepr(expr1) == srepr(expr2)
True
(possible solution): Is writing a transformation rule the best possible solution to tackle this? https://docs.sympy.org/latest/modules/parsing.html#parsing-transformations-reference
Folks I have a expression I don't know how to simplify:
from sympy import *
from sympy.abc import w, x, y, z
expr = (w - x) * (x - y) + (y - z) * (z - w)
expanded = expand(expr)
back = factor(expr)
I want back
to be something similar to expr
. I tried factor/simplify/cancel
and stuff and seems non of these works.
Anyone know what should I try?
Hi @jagt factor()
takes a polynomial and factors it into irreducible factors over the rational numbers. Note: factors may not be irreducible if the input is no longer a polynomial over the rationals.
To confirm what will be the factors you can do the following:factor_list()
instead of factor
which will return the expected factors or output of factor()
in a more structured way.
Hi all, I had a quick question on covariance calculations. I'm no expert, but for some reason Sympy is different than what I'd expect. I'm probably using the wrong function somewhere. Here is a quick snippet:
covariance(FiniteRV('Jimmy', density={-.20: .40, .30: .60}), FiniteRV('Walter', density={.40: .40, -.20: .60}))
# expect -0.072
And the equation I'm using: https://wikimedia.org/api/rest_v1/media/math/render/svg/18143cb5b668ff2cc739385a5916d9317bb74df0
sympy
is at finding the angle between lines that are given in terms of points with symbolic coordinates. Is there a flag to disable symbolic computation across all sympy
objects? Having to remember to call .evalf()
is far from ideal... I had to spend a great deal of time understanding why my code was running incredibly slow.
The following code plots the graph of a simple piecewise-constant function f
such that f(x) = 1 for x between 0 and 1
and f(x) = -1 for x between 1 and 2
and f(x) = 0 otherwise.
In this plot, the graph is plotted for x between -1 and 3.
However, vertical lines are drawn at the values of x where there are discontinuities.
Is there a way to plot the graph of this function such that the vertical lines (which should not be part of the graph) are not drawn?
from sympy import symbols
from sympy.plotting import plot
from sympy import Piecewise
x = symbols('x')
s = Piecewise((1, (x >= 0) & (x <= 1)), (-1, (x >= 1) & (x <= 2)), (0, True))
plot(s,(x,-1,3))