You can use numpy.linspace() to create the values of the x axis (x_vals in the code below) and lambdify(). from sympy import symbols from numpy import linspace from sympy import lambdify import matplotlib.pyplot as mpl t = symbols(‘t’) x = 0.05*t + 0.2/((t – 5)**2 + 2) lam_x = lambdify(t, x, modules=[‘numpy’]) x_vals = linspace(0, … Read more
Since you’ve tagged this question with sympy, I will give such an example. From the documentation: http://docs.sympy.org/latest/modules/plotting.html. from sympy import var, plot_implicit var(‘x y’) plot_implicit(x*y**3 – y*x**3)
SymPy can solve Diophantine equations but doesn’t have a built-in way to generate positive solutions. With Sage one can do that easily: here is four-line code that generates all nonnegative integer solutions of your equation. p = MixedIntegerLinearProgram() w = p.new_variable(integer=True, nonnegative=True) p.add_constraint(411*w[0] + 295*w[1] + 161*w[2] == 3200) p.polyhedron().integral_points() The output is ((4, 2, … Read more
To substitute several values: >>> from sympy import Symbol >>> x, y = Symbol(‘x y’) >>> f = x + y >>> f.subs({x:10, y: 20}) >>> f 30
Currently, there is no way in SymPy to print things exactly as they are entered, because that information isn’t even saved anywhere. I believe in a multiplication, symbols are ordered alphabetically, with capital letters coming before lowercase letters (basically, the order from ord). The best trick I can come up with is to use the … Read more
Nice find! The documentation doesn’t make things clear. Diving into the source code, leads to these lines in plot.py: for marker in parent.markers: # make a copy of the marker dictionary # so that it doesn’t get altered m = marker.copy() args = m.pop(‘args’) ax.plot(*args, **m) So, sympy just calls matplotlib’s plot with: the args … Read more
Your problem is with namespace clash, here from sympy import * from numpy import * Since both numpy and and sympy have their own definition of cos. The error is telling you that the Mul object (which is n*x) does not have a cosine method, since the interpreter is now confused between the sympy and … Read more
First of all, at the moment SymPy does not guarantee support for numpy arrays which is what you want in this case. Check this bug report http://code.google.com/p/sympy/issues/detail?id=537 Second, If you want to evaluate something numerically for many values SymPy is not the best choice (it is a symbolic library after all). Use numpy and scipy. … Read more
From the SymPy documentation == represents exact structural equality testing. “Exact” here means that two expressions will compare equal with == only if they are exactly equal structurally. Here, (x+1)^2 and x^2+2x+1 are not the same symbolically. One is the power of an addition of two terms, and the other is the addition of three … Read more
all_coeffs() can be sometime better than using coeffs() for a Poly. The difference lies in output of these both. coeffs() returns a list containing all coefficients which has a value and ignores those whose coefficient is 0 whereas all_coeffs() returns all coefficients including those whose coefficient is zero. >>> a = Poly(x**3 + a*x**2 – … Read more