OpenPRC: Physical Reservoir Computing Framework

OpenPRC is a modular, GPU-accelerated Python framework for simulating and evaluating physical reservoir computers — mechanical systems that process information through their intrinsic dynamics.

If you use OpenPRC in your research, please cite:

@article{phalak2026openprc,
  title={OpenPRC: A Unified Open-Source Framework for Physics-to-Task Evaluation in Physical Reservoir Computing},
  author={Phalak, Yogesh and Lor, Wen Sin and Khairnar, Apoorva and Jantzen, Benjamin and Naughton, Noel and Li, Suyi},
  journal={arXiv preprint arXiv:2604.07423},
  year={2026}
}

---

Simulation Capabilities

OpenPRC supports diverse mechanical substrates ranging from compliant mass-spring networks to rigid-foldable origami. Below are examples of validated simulation outputs:

DJI Matrice 600 Aerial platform dynamics
Soft Reservoir Network Mass-spring lattice under dynamic actuation	Miura-Ori Tessellation Rigid-foldable origami pattern
Kirigami Structure Compliant network with geometric cuts	K-Cone Origami Non-periodic origami configuration
Bistable Slab Multistable mechanical metamaterial	Tapered Spring Nonlinear elastic element dynamics

---

Installation

pip install openprc

# With GPU support
pip install openprc[cuda]

# With all optional dependencies
pip install openprc[full]

Dependencies

Package	Purpose	Extra
numpy, h5py, scipy	Core numerics and I/O	(always)
numba	JIT-compiled CPU physics	(always)
scikit-learn	Ridge readout	(always)
pycuda	CUDA backend	[cuda]
jax / jaxlib	Differentiable JAX backend	[jax]
piviz-3d, imgui	3-D animator	[viz]
opencv-python	Vision utilities	[vision]
trimesh, rosbags, yourdfpy	Robot bundle tooling	[automod]

---

Pipeline

┌─────────────┐     ┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   demlat    │────▶│   reservoir │────▶│   analysis  │────▶│  optimize   │
│  (Physics)  │     │  (Readout)  │     │(Diagnostics)│     │(Calibration)│
└─────────────┘     └─────────────┘     └─────────────┘     └─────────────┘

---

Quick Start

import numpy as np
from openprc.demlat import SimulationSetup, Simulation, Engine, ShowSimulation

EXP = "experiments/my_prc"

# ── 1. Build geometry ──────────────────────────────────────────────────────
setup = SimulationSetup(EXP, overwrite=True)
setup.set_simulation_params(duration=10.0, dt=0.001, save_interval=0.01)
setup.set_physics(gravity=-9.81, damping=0.1)

anchor = setup.add_node([0.0, 0.0, 0.0], fixed=True)
mass   = setup.add_node([1.0, 0.0, 0.0], mass=1.0)
setup.add_bar(anchor, mass, stiffness=1e4, rest_length=1.0, damping=5.0)

# ── 2. Drive with a force signal ──────────────────────────────────────────
t   = np.arange(0, 10.0, 0.001)
sig = np.stack([0.5 * np.sin(2 * np.pi * t),
                np.zeros_like(t),
                np.zeros_like(t)], axis=1).astype("float32")
setup.add_signal("drive", sig, dt=0.001)
setup.add_actuator(anchor, "drive", type="force")
setup.save()

# ── 3. Run (CUDA, or "cpu" / "jax") ──────────────────────────────────────
eng = Engine(backend="cuda")          # BarHingeModel is the default
eng.run(Simulation(EXP))

# ── 4. Animate ────────────────────────────────────────────────────────────
ShowSimulation(EXP)

---

API Reference

demlat — Physics Simulation

from openprc.demlat import SimulationSetup, Simulation, Engine, ShowSimulation

# ── Geometry ──────────────────────────────────────────────────────────────
setup = SimulationSetup("./experiments/my_exp", overwrite=True)
setup.set_simulation_params(duration=5.0, dt=0.001, save_interval=0.01)
setup.set_physics(
    gravity=-9.81, damping=0.1,
    enable_collision=True,          # node-level sphere collision
    collision_radius=0.02,
    collision_restitution=0.6,
    collision_iterations=3,
)

n0 = setup.add_node([0.0, 0.0, 0.0], fixed=True,  collidable=True)
n1 = setup.add_node([0.5, 0.0, 0.0], mass=1.0,    collidable=True)
n2 = setup.add_node([0.5, 0.5, 0.0], mass=1.0)

setup.add_bar(n0, n1, stiffness=1e4, rest_length=0.5, damping=5.0)
setup.add_hinge([n0, n1, n2, n2], stiffness=50.0, rest_angle=np.pi / 2)

# ── Signals & Actuators ───────────────────────────────────────────────────
t   = np.arange(0, 5.0, 0.001)
pos = np.stack([0.1 * np.sin(2 * np.pi * t),
                np.zeros_like(t),
                np.zeros_like(t)], axis=1).astype("float32")
setup.add_signal("wave", pos, dt=0.001)

setup.add_actuator(n0, "wave", type="position")              # full 3-DOF
setup.add_actuator(n1, "wave", type="force", dof=[0, 0, 1]) # z-axis only
setup.save()

# ── Run ───────────────────────────────────────────────────────────────────
eng = Engine(backend="cuda")   # or "cpu" / "jax"; BarHingeModel is default
eng.run(Simulation("./experiments/my_exp"))

ShowSimulation("./experiments/my_exp")

reservoir — Readout Training

from openprc.reservoir import StateLoader, Ridge, Trainer, features

loader = StateLoader("./experiments/my_exp/output/simulation.h5")

# Node position features for selected nodes
feat = features.NodePositions(node_ids=[0, 1, 2], dims="all")
X    = feat.transform(loader)          # (T, n_features)

# Or use bar strains as the observable (stored as ε = ΔL/L₀)
feat = features.BarStrains()

# Train ridge readout
readout = Ridge(regularization=1e-4)
trainer = Trainer(
    features=feat,
    readout=readout,
    experiment_dir="./experiments/my_exp",
    loader=loader,
    washout=2.0,          # seconds to discard at start
    train_duration=6.0,
    test_duration=2.0,
)

y_target = ...            # (T,) or (T, n_outputs) numpy array
result = trainer.train(y_target, task_name="NARMA10")
result.save()

analysis — Correlation Diagnostics & Multistability

from openprc.analysis import correlation as corr
from openprc.analysis import EquilibriumFinder

# ── Correlation diagnostics (x: features, y: targets) ────────────────────
lin = corr.Linear(x, y, lag_sweep=True)
print(lin.pearson)         # zero-lag Pearson r per channel
lin.ccf.plot()             # cross-correlation lag profiles

nr = corr.Nonparametric(x, y)
print(nr.dcor)             # distance correlation (detects nonlinear deps)

# ── Find all mechanical equilibria ───────────────────────────────────────
finder  = EquilibriumFinder.from_experiment("./experiments/my_exp")
results = finder.find_all(num_random=50)
results.summary()
finder.save_results(results, "./experiments/my_exp/equilibria.h5")

optimize — JAX-Based Parameter Calibration

from openprc.optimize import Calibration

from openprc.demlat import BarHingeModel
cal = Calibration(BarHingeModel, backend="jax")

cal.load_geometry("./experiments/my_exp")
cal.load_reference("./experiments/my_exp/output/simulation.h5")

cal.optimize_params(bar_stiffness=True, hinge_stiffness=True)
cal.set_bounds(bar_stiffness=(10.0, 1e5))

result = cal.run(max_iterations=500, lr=0.01, cost="mse")
cal.save("./experiments/my_exp/optimized_geometry.h5")

automod — Robot PRC Pipeline

import openprc.automod as automod

# Stage 1: convert URDF links to spring-mass reservoirs
automod.batch_preprocess(
    bundle_dir="./robot_bundle",
    robot_name="go1",
    params=automod.PRESETS["small"],   # "small", "medium", "large"
)

# Stage 2: run DEMLAT simulations for all trajectories
automod.batch_simulate(
    bundle_dir="./robot_bundle",
    robot_name="go1",
    splits=("train", "test"),
    gravity=-9.81, damping_scale=2.0,
)

# Stage 3: train ridge readout with k-fold CV
run_dir = automod.run_training(
    bundle_dir="./robot_bundle",
    robot_name="go1",
    features="node_vel",              # see automod.FEATURE_LEVELS
    targets=["body_vel", "qvel"],
    n_folds=5,
)

# Stage 4: generate plots
automod.plot_run(run_dir)

---

License

Apache 2.0 — see LICENSE.