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
I'm playing with sympy as a possible way of doing some (relatively basic) probability calculations, using the
sympy.Stats module. Doing something like X, Y = Die('X', 6), Die('Y', 6); density(X+Y) is neat, but if I wanted to get the distribution of the highest of the 2 rolls, how would I do that? density(max(X,Y)) doesn't work - I can see why, but I don't know where to look in the docs for something equivalent that would work. What's the best way for me to learn how to model calculations like this?
3 replies
Hello developers,
I am Kuldeep Borkar from Maharashtra
in 1st year of B.tech Artificial Intelligence,
I was just looking for a great opportunity to make a great contribution to this organization and I found GSOC. It would be great help if I am guided for making contributions and yes join community to work on a project. I am comfortable with Python and C programming. I just now want to start making contributions to this organization, resolve issues and wish to collaborate with community.
I am Kuldeep Borkar from Maharashtra
in 1st year of B.tech Artificial Intelligence,
I was just looking for a great opportunity to make a great contribution to this organization and I found GSOC. It would be great help if I am guided for making contributions and yes join community to work on a project. I am comfortable with Python and C programming. I just now want to start making contributions to this organization, resolve issues and wish to collaborate with community.
We are hoping to apply to Google Season of Docs this year with a project to improve the organization of our documentation.
2 replies
If I have a Tuple() object, can I do .simplify() to simplify the elements in inplace?
should you be able to use generators? Tuple((simplify(x) for x in y)) ?
There are no in-place operations in SymPy. All objects are immutable.
a,b=symbols('a,b',is_positive=True)
simplify((a2-b2)/abs(a2-b2),assuming=a>b)
actually even a/abs(a) doesn't
or maybe the positive bit isn't working
a/abs(a) works if you declare a=symbols('a', positive=True)
there is some difference between positive=True and is_positive=True
you can check by looking at a.assumptions0
I tried assigning FiniteField instances into a matrix, but they just get recalled as integers.
Hello, I'm another beginner here and would want to help.
First-time involvement in open source is, probably, a good chance to ask the first a bit silly question, so mine is:
How strong should be someone's math background for contributing to this library? Is there any room for entry-level skills students?
Thanks
First-time involvement in open source is, probably, a good chance to ask the first a bit silly question, so mine is:
How strong should be someone's math background for contributing to this library? Is there any room for entry-level skills students?
Thanks
2 replies
from sympy import *
from sympy.abc import x
f = x
maximum(f, x)
this gives me infinity. what exactly this means? The question might be a bit silly. But I am beginner here.
@hitblunders Hi, I am assuming you understand what does maximum () does. If not, here's a simple explanation: it returns the maximum value of the function, in your case the function is x. You can also change the domain as per your requirement. Here's the relevant link
https://docs.sympy.org/latest/modules/functions/elementary.html
https://docs.sympy.org/latest/modules/functions/elementary.html
Hi, There a way to solve this with Sympy ? Thx in advance!
@metabsd yeah there definitely is
Link to sympy tutorial https://docs.sympy.org/latest/tutorial/index.html
x = symbols('x')f = (6*x+13)/(15) - 2*x/5 -(3*x+5)/(5*x-25)solveset(f,x) # OUTPUTS 20Link to sympy tutorial https://docs.sympy.org/latest/tutorial/index.html
I have two PR's which have more or less been reviewed so far: sympy/sympy#20915 and sympy/sympy#20916. Would appreciate if someone could finally approve those rather small changes.
If I have an expression like ax + at + bx - bt, how do I ask sympy to factor this so that it has terms like x+t and x-t and not a+b and a-b.
@aplund:matrix.org you could work with multivariate polynomials (instead of expressions) so that you can specify the polynomial variables e.g.
>>> from sympy import *
>>> a, b, t, x = symbols("a b t x")
>>> expr = a*t + a*x - b*t + b*x
>>> factor(expr)
a*t + a*x - b*t + b*x
>>> Poly(expr, a, b)
Poly((t + x)*a + (-t + x)*b, a, b, domain='ZZ[x,t]')
>>> Poly(expr, t, x)
Poly((a - b)*t + (a + b)*x, t, x, domain='ZZ[a,b]')Alternately, you could stick with expressions and use collect e.g.
>>> collect(expr, [a, b])
a*(t + x) + b*(-t + x)
>>> collect(expr, [t, x])
t*(a - b) + x*(a + b)
is there a nice way to perform these manipulations deeper in the syntax tree? I've got expressions like exp(ax + at + bx - bt), but collect won't work inside the exponential. Do I just have to manually rebuild the syntax tree?
Does anyone use sympy with numpy and dill? The following code does not work when numpy gets upgraded to 1.20.1 but works fine with numpy=1.19. Running SymPy 1.7.1 and dill 0.3.3.
import dill
import sympy
from sympy.abc import x
dill.settings['recurse'] = True
expr = sympy.sympify('re(x)')
lfunc = sympy.lambdify(x, expr, 'numpy')
with open("out.pkl", 'wb') as f:
dill.dump(lfunc, f)RecursionError: maximum recursion depth exceeded while calling a Python object
The issue occurs when re or im appears in an expression. Changing re to functions such as log works. Any clue about a fix?