Plotting

These functions are for visualizing simulation results.

Trajectory

example_gni_project.plot_trajectory(simulation: SimulationResult, filename=None)

Plot the entire discrete trajectory. The figure contains one line plot for every component of the state space.

Parameters:

  • simulation (SimulationResult) –

  • filename (str) – If a filename (path) is provided, the plot is saved.

Phase portrait

example_gni_project.plot_phase_portrait(simulation: SimulationResult, x=0, y=1, filename=None)

Plot the phase portrait.

Parameters:

  • simulation (SimulationResult) –

  • x (int) – Index of the component that is plotted on the x-axis.

  • y (int) – Index of the component that is plotted on the y-axis.

  • filename (str) – If a filename (path) is provided, the plot is saved.

Observables

example_gni_project.plot_observable(simulation: SimulationResult, name: str, observable, filename=None)

Plot the evolution of an observable (scalar-valued function of the state).

Parameters:

  • simulation (SimulationResult) –

  • name (str) – name / plot title

  • observable (function) – scalar-valued function of the state (e.g. energy)

  • filename (str) – If a filename (path) is provided, the plot is saved.

Example

Plot just the first component of the state:

>>> import autograd.numpy as np
>>> from example_gni_project import *
>>> def vector_field(x):
...     q, p = x
...     return np.array([p, -q])
>>> ivp = IVP(("q", "p"), vector_field, np.array([1., 0.]))
>>> simulation = simulate(ivp, explicit_euler, 0.1, 0.5)
>>> plot_observable(simulation, "q", lambda x: x[0])