Creating Van der Pol oscillator class with data frames

I'm trying to recreate this graph:

... and this table:

... using this set of equations:

It has to include these methods:

Instructions: Create a class that can be used to simulate Van der Pol oscillators. That class should contain at least the following methods:

• add_oscillator(self, mu, x0=1, y0=0): Add a new oscillator with parameters mu initial values x(0)=x0 (default: 1) and y(0)=y0 (default: 0).
• delete_oscillator(self, i): Delete the i-th 开发者_开发技巧oscillator from the list of available oscillators.
• getsim_data(self, duration=30.0, dt=0.01): Simulate the N oscillators previously added to the object (using add_oscilator) for the specified duration (default: 30s) and with a sampling step dt (default: 0.01s) and return the simulated data as a pandas DataFrame of shape (duration/dt, N). "Simulating" these oscillators mean obtaining x(t) by solving the ODE above. This can be done manually using the Euler integration scheme (as seen in previous labs) or using an ODE solver (e.g., scipy.solve_ivp() function).
• plot(fself, tmin=0.0, tmax=30.0): Plot the time course of the different oscillators from tmin to tmax.

Here is an example of use:

vdp = VanDerPol()
vdp.add_oscillator(1.0)  # oscilator 0
vdp.add_oscillator(3.0)  # oscilator 1
vdp.add_oscillator(2.0)  # oscilator 2
vdp.delete_oscilator(1)
print(vdp.get_sim_data(dt=0.01))
vdp.plot(tmin=10)

I am trying to create a Python class to simulate a Van der Pol oscillator using numpy, scipy, DataFrame, and matplotlib.

This is my first exposure to coding, so I'm aware my code might be very junky.

I started off by completing the add_oscillator and delete_oscillator functions. Both seem to work, though I'm unsure if the new_oscillator class is the best way to achieve what I did.

I began running into problems in get_sim_data. I used information from this link to get a function working, and then adding the data to a DataFrame. The resulting data seems to be wrong, and I'm not sure where the mistake is.

The graphed plot also doesn't look like what I need it to look alike, and the x-axis numbers are 0-3000, instead of 10-30.

Any help is appreciated. Thanks.

from scipy.integrate import solve_ivp
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt


class VanDerPol:
    def __init__(self):
        self.oscillators = []
        self.df = pd.DataFrame()

    def add_oscillator(self, mu, x0=1, y0=0):
        class new_oscillator:
            def __init__(self, mu, x0, y0):
                self.mu = mu
                self.x0 = x0
                self.y0 = y0

            def __str__(self):
                return f"mu={self.mu}, x0={self.x0}, y0={self.y0}"

        self.oscillators.append(new_oscillator(mu, x0, y0))

    def delete_oscillator(self, i):
        self.oscillators.pop(i)

    def get_sim_data(self, duration=30.0, dt=0.01):
        # durations = np.arange(0, duration, dt, dtype=float)
        durations = np.linspace(0, duration, int(duration / dt))
        # df = pd.DataFrame(durations)

        for o in self.oscillators:

            def vdp(t, z):
                x, y = z
                return [y, o.mu * (1 - x**2) * y - x]

            data = solve_ivp(vdp, [0, duration], [o.x0, o.y0], t_eval=durations)
            # df = pd.DataFrame(data.y[0])
            # df = pd.DataFrame()
            df = pd.DataFrame(data.y[0])
            # df[o] = pd.Series(data.y[0])
            # print(data.y[0])
            self.df[o] = df
            # print(self.df)
            print(self.df)

    def plot(self, tmin=0.0, tmax=30.0):
        plt.plot(self.df)


vdp = VanDerPol()
vdp.add_oscillator(1.0)  # oscillator 0
vdp.add_oscillator(3.0)  # oscillator 1
vdp.add_oscillator(2.0)  # oscillator 2
vdp.delete_oscillator(1)
print(vdp.get_sim_data(dt=0.01))
vdp.plot(tmin=10)