poscidyn 0.1.5

Fast Simulation of Nonlinear Oscillator Dynamics in Python

Poscidyn

Fast Simulation of Nonlinear Oscillator Dynamics in Python

Poscidyn (Python oscillator dynamics) is a Python toolkit based on JAX, designed to streamline and accelerate time-response and frequency-sweep simulations. It leverages novel parallelization strategies to gain a speed advantages over standard continuation software.

Features include:

• Frequency sweep simulation (forward and backward)
• Time-response simulation
• Built-in models of (nonlinear) oscillators
• Everything vmappable (batchable)

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Installation

pip install poscidyn[gpu]

Requires Python 3.10 or newer.

Documentation

Have a look at our extensive documentation on how to install, use and extend this package: https://rknetemann.github.io/poscidyn/.

Quick example

import poscidyn
import numpy as np

Q, omega_0, a, b = np.array([50.0, 50.0]), np.array([1.00, 2.00]), np.zeros((2, 2, 2)), np.zeros((2, 2, 2, 2))
a[0,0,1] = 2.0
a[1,0,0] = 1.0
b[0,0,0,0] = 1.0
modal_forces = np.array([1.0, 1.0])
modal_contributions = np.array([1.0, 1.0])

driving_frequency = np.linspace(0.9, 1.13, 256)
driving_amplitude = np.linspace(0.1, 1.0, 8) * 0.0144

model = poscidyn.Nonlinear(Q=Q, a=a, b=b, omega_0=omega_0)
excitation = poscidyn.DirectExcitation(driving_frequency, driving_amplitude, modal_forces)
solver = poscidyn.TimeIntegration(max_steps=4096 * 20, n_time_steps=100, rtol=1e-5, atol=1e-7, t_steady_state_factor=2.0)
response_measure = poscidyn.Demodulation(multiples=(1,), modal_contributions=modal_contributions)

frequency_sweep = poscidyn.frequency_sweep(
    model = model, excitation=excitation, solver=solver, response_measure=response_measure, precision=poscidyn.Precision.DOUBLE
) 

Credits where they are due

JAX: a Python library for accelerator-oriented array computation and program transformation, designed for high-performance numerical computing and large-scale machine learning.

Diffrax: JAX-based library providing numerical differential equation solvers.

Equinox: your one-stop JAX library, for everything you need that isn't already in core JAX.