initial commit of particle cloud classes

pyproject.toml

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+[build-system]
+requires = ["setuptools>=61"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "particle-cloud"
+version = "0.0.1"
+description = "particle cloud computations"
+requires-python = ">=3.10"
+dependencies = []
+
+[tool.setuptools.packages.find]
+where = ["src"]

src/particle_cloud/__init__.py

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+from .stuff import Particle, cloud
+
+__all__ = ["Particle", "cloud"]

src/particle_cloud/stuff.py

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+class Particle:
+    def __init__(self, mass=1.0, velocity=None, position=None):
+        self.mass = mass
+        self.velocity = list(velocity if velocity is not None else [0.0, 0.0, 0.0])
+        self.position = list(position if position is not None else [0.0, 0.0, 0.0])
+
+    def __repr__(self):
+        return f"Particle(mass={self.mass}, velocity={self.velocity}, position={self.position})"
+
+
+class cloud:
+    def __init__(self, particles=None):
+        self.particles = list(particles or [])
+
+    def add(self, p):
+        self.particles.append(p)
+
+    def step(self, dt=1.0):
+        for p in self.particles:
+            p.position = [x + v * dt for x, v in zip(p.position, p.velocity)]
+        return self
+
+    def center(self):
+        total = sum(p.mass for p in self.particles)
+        if total == 0:
+            return [0.0, 0.0, 0.0]
+        answer = [0.0, 0.0, 0.0]
+        for p in self.particles:
+            answer = [a + p.mass * x for a, x in zip(answer, p.position)]
+        return [x / total for x in answer]
+
+    def __repr__(self):
+        return f"cloud({self.particles})"