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70 lines
1.7 KiB
70 lines
1.7 KiB
#!/usr/local/bin/python3
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"""
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Script to generate a fixture of a chain with N simple links.
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Usage: python generate_simple_chainmail_fixture.py N
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"""
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import json
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import pathlib
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import sys
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import numpy
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from fixture_utils import *
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vertices = numpy.array(
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[
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[-1.5 * 1.625, 0.0],
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[0.0, 0.0],
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[1.5 * 1.625, 0.0],
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[-3.0, -3.0],
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[0.0, -3.0],
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[3.0, -3.0],
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[-3.0, -6.0],
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[-1.5 * 0.375, -6.0],
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[1.5 * 0.375, -6.0],
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[3.0, -6.0],
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],
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dtype=float,
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)
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edges = numpy.array(
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[[0, 1], [1, 2], [1, 4], [3, 4], [4, 5], [3, 6], [5, 9], [6, 7], [8, 9]],
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dtype=int)
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def generate_fixture(n_links: int) -> dict:
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"""Generate a fixture of a chain with N simple links."""
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fixture = generate_default_fixture()
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rigid_bodies = fixture["rigid_body_problem"]["rigid_bodies"]
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for i in range(n_links):
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rigid_bodies.append({
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"vertices": (vertices + [0, -4.5 * i]).tolist(),
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"edges": edges.tolist(),
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"velocity": [0.0, -1.0 if i else 0.0, 0.0],
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"is_dof_fixed": [i == 0, i == 0, i == 0],
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})
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return fixture
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def main() -> None:
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"""Parse command-line arguments to generate the desired fixture."""
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assert len(sys.argv) >= 2
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n_links = int(sys.argv[1])
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fixture = generate_fixture(n_links)
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if len(sys.argv) > 2:
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out_path = pathlib.Path(sys.argv[2])
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out_path.parent.mkdir(parents=True, exist_ok=True)
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else:
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directory = pathlib.Path(
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__file__).resolve().parents[1] / "fixtures" / "chain"
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directory.mkdir(parents=True, exist_ok=True)
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out_path = directory / f"simple_{n_links:d}_link_chain.json"
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save_fixture(fixture, out_path)
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if __name__ == "__main__":
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main()
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