"""
Tests the Coulomb friction interaction between two agents as one slides over the other.
Tests cover:
- Time and position continuity for each agent
- Near-zero angular velocity (omega) and near constant orientation (theta) for all agents
- Agents 0 and 1 should remain static translationally: translational velocity ~ 0, x and y coordinates ~ constants
- Velocity of Agent 2 should be positive along the x-axis during the slip
"""
# Copyright 2025 Institute of Light and Matter, CNRS UMR 5306, University Claude Bernard Lyon 1
# Contributors: Oscar DUFOUR, Maxime STAPELLE, Alexandre NICOLAS
# This software is a computer program designed to generate a realistic crowd from anthropometric data and
# simulate the mechanical interactions that occur within it and with obstacles.
# This software is governed by the CeCILL-B license under French law and abiding by the rules of distribution
# of free software. You can use, modify and/ or redistribute the software under the terms of the CeCILL-B
# license as circulated by CEA, CNRS and INRIA at the following URL "http://www.cecill.info".
# As a counterpart to the access to the source code and rights to copy, modify and redistribute granted by
# the license, users are provided only with a limited warranty and the software's author, the holder of the
# economic rights, and the successive licensors have only limited liability.
# In this respect, the user's attention is drawn to the risks associated with loading, using, modifying
# and/or developing or reproducing the software by the user in light of its specific status of free software,
# that may mean that it is complicated to manipulate, and that also therefore means that it is reserved
# for developers and experienced professionals having in-depth computer knowledge. Users are therefore
# encouraged to load and test the software's suitability as regards their requirements in conditions enabling
# the security of their systems and/or data to be ensured and, more generally, to use and operate it in the
# same conditions as regards security.
# The fact that you are presently reading this means that you have had knowledge of the CeCILL-B license and that
# you accept its terms.
import subprocess
from pathlib import Path
import numpy as np
import pandas as pd
import pytest
from configuration.backup import xml_to_Chaos
#: Tolerance for the constancy of the decisional time step used throughout the simulation (s).
TIME_TOL = 1e-4
#: Maximum allowed spatial jump (m) between consecutive time steps for each agent.
MAX_SPATIAL_JUMP = 1
#: Minimum velocity allowed for agent 2 along x during slip phase (m/s).
VX_TOL = 1e-2
#: Tolerance for near-zero velocities of agent 0 and 1 along x during the whole simulation (m/s).
VX_CONTACT_TOL = 0.5
#: Tolerance for near-zero velocities of agent 0 and 1 along y during the whole simulation (m/s).
VY_CONTACT_TOL = 0.5
#: Tolerance for near-zero angular velocities of all agents during the whole simulation (rad/s).
OMEGA_CONTACT_TOL = 0.5
#: Maximum allowed range for orientation (theta) of all agents during the whole simulation (radians).
DELTA_THETA_CONTACT_TOL = 0.5
#: Maximum allowed range for x of agents 0 and 1 during the whole simulation (m).
DELTA_X_CONTACT_TOL = 0.5
#: Maximum allowed range for y of agents 0 and 1 during the whole simulation (m).
DELTA_Y_CONTACT_TOL = 0.5
[docs]
@pytest.fixture(scope="session")
def df() -> pd.DataFrame:
"""
Export to CSV the XML files and load the time series once per test session.
Returns
-------
pd.DataFrame
DataFrame containing all time series.
"""
subprocess.run(
["uv", "run", "python", "run_simulation.py"],
check=True,
)
filenameCSV = "all_trajectories.csv" # Name of the final CSV file we’ll generate
PathXML = Path("inputXML") # Folder path where the XML files are located
PathCSV = Path("inputCSV") # Folder path where CSV files will be saved
PathCSV.mkdir(parents=True, exist_ok=True) # Create directories if it doesn't exist
xml_to_Chaos.export_XML_to_CSV(PathCSV, PathXML)
return pd.read_csv(PathCSV / filenameCSV)
[docs]
def test_time_and_position_continuity(df: pd.DataFrame) -> None:
"""
Test time and position continuity for each agent.
Parameters
----------
df : pd.DataFrame
DataFrame containing all time series.
"""
required_cols = {"ID", "t", "x", "y"}
missing = required_cols - set(df.columns)
assert not missing, f"Missing expected columns: {missing}"
# agent IDs with irregular time steps
violations_missing_time: list[int] = []
# (agent_id, list of jump distances > MAX_SPATIAL_JUMP)
violations_big_jump: list[tuple[int, list[float]]] = []
for agent_id, g in df.sort_values("t").groupby("ID"):
t = g["t"].to_numpy()
dt = np.diff(t)
ddt = np.diff(dt)
if not np.all(np.abs(ddt) < TIME_TOL):
violations_missing_time.append(int(agent_id))
x = g["x"].to_numpy()
y = g["y"].to_numpy()
dist = np.sqrt(np.diff(x) ** 2 + np.diff(y) ** 2)
bad_jump_idx = np.where(dist > MAX_SPATIAL_JUMP)[0]
if bad_jump_idx.size > 0:
violations_big_jump.append((int(agent_id), dist[bad_jump_idx].tolist()))
assert not violations_missing_time, f"Irregular time steps: {violations_missing_time}"
assert not violations_big_jump, f"Large spatial jumps: {violations_big_jump}"
[docs]
def test_omega_near_zero_and_theta_near_constant(df: pd.DataFrame) -> None:
"""
Test near-zero angular velocity (omega) and near constant orientation (theta) for all agents over the whole simulation.
Parameters
----------
df : pd.DataFrame
DataFrame containing all time series.
"""
required_cols = {"ID", "omega", "theta"}
missing = required_cols - set(df.columns)
assert not missing, f"Missing expected columns: {missing}"
violations_omega: list[tuple[int, float]] = []
violations_theta: list[tuple[int, float]] = []
for agent_id, g in df.groupby("ID"):
max_abs_omega = float(g["omega"].abs().max())
if max_abs_omega > OMEGA_CONTACT_TOL:
violations_omega.append((agent_id, max_abs_omega))
theta_range = np.abs(g["theta"].max() - g["theta"].min())
if theta_range > DELTA_THETA_CONTACT_TOL:
violations_theta.append((agent_id, theta_range))
assert not violations_omega, f"omega not ~0 for some agents: {violations_omega}"
assert not violations_theta, f"theta not constant for some agents: {violations_theta}"
[docs]
def test_agents_0_and_1_static(df: pd.DataFrame) -> None:
"""
Test that agents 0 and 1 remain static translationally: translational velocity ~ 0, x and y coordinates ~ constants.
Parameters
----------
df : pd.DataFrame
DataFrame containing all time series.
"""
required_cols = {"ID", "vx", "vy", "x", "y"}
missing = required_cols - set(df.columns)
assert not missing, f"Missing expected columns: {missing}"
violations: list[tuple[int, dict[str, float]]] = []
for static_id in (0, 1):
g = df[df["ID"] == static_id]
assert not g.empty, f"No data for agent {static_id}"
max_vx = float(g["vx"].abs().max())
max_vy = float(g["vy"].abs().max())
if (max_vx > VX_CONTACT_TOL) or (max_vy > VY_CONTACT_TOL):
violations.append((static_id, {"max_vx": max_vx, "max_vy": max_vy}))
x_range = np.abs(g["x"].max() - g["x"].min())
y_range = np.abs(g["y"].max() - g["y"].min())
if x_range > DELTA_X_CONTACT_TOL or y_range > DELTA_Y_CONTACT_TOL:
violations.append((static_id, {"x_range": x_range, "y_range": y_range}))
assert not violations, f"Agents 0 and/or 1 are not static: {violations}"
[docs]
def test_agent_2_positive_vx_during_slip(df: pd.DataFrame) -> None:
"""
Test that the velocity of Agent 2 is positive along the x-axis during the slip phase (x < 2.8 meters).
Parameters
----------
df : pd.DataFrame
DataFrame containing all time series.
"""
required_cols = {"ID", "t", "vx", "x"}
missing = required_cols - set(df.columns)
assert not missing, f"Missing expected columns: {missing}"
g = df[df["ID"] == 2].sort_values("t")
assert not g.empty, "No data for agent 2"
# slip phase is for x smaller than 2.8 meters
slip_phase = g[g["x"] < 2.8]
moving = slip_phase[slip_phase["vx"].abs() > VX_TOL]
assert not moving.empty, "Agent 2 never moves significantly"