dsolve error: 'numpy.ndarray' object is not callable

Question

import sympy as sp
sp.init_printing()
%matplotlib notebook
import numpy as np
import matplotlib.pyplot as plt
from IPython.display import display

Can somebody help me please?

Welcome to SO. [Don't screenshot code](https://meta.stackoverflow.com/questions/303812/discourage-screenshots-of-code-and-or-errors) — Crispin, Mar 19 '17 at 09:23

score 0 · Answer 1 · edited May 23 '17 at 12:00

0

The variable y is a numpy.ndarray, not a callable, which means it cannot be used like a function (or other callable) would: y(); only indexed, like y[]. You probably meant to write sp.Derivative(y[x],x).

edited May 23 '17 at 12:00

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answered Mar 19 '17 at 09:17

Crispin

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score 0 · Answer 2 · edited May 23 '17 at 12:00

I suspect that you want to solve a differential equation involving only scalar variables.

>>> import sympy as sp
>>> sp.var('x')
x
>>> f = sp.Function('f')
>>> sp.dsolve(sp.Derivative(f(x),x)-(1/(1+x**2)-2*f(x)**2))
Eq(f(x), x**3*(2*C1*(C1 - 1) - 1)/3 + x**5*(C1*(16*C1*(-9*C1 + 1) - 13*C1 + 2) - 20*C1 + 12)/30 + C1 + C1*x + C1*x**4*(13*C1 + 2)/6 - C1**2*x**2 + O(x**6))

If you have an initial condition and need to solve for the arbitary constant then Represent a first order differential equation in numpy might help. (I don't know for sure.)

dsolve error: 'numpy.ndarray' object is not callable

2 Answers2