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Particle life

Particle Life model.

ParticleLife

Particle Life model.

The Particle Life model is a simple model of particle behaviour, where particles are either attracted or repelled by other particles, depending on their species. Popularised by Jeffrey Ventrella (Clusters), Tom Mohr and others:

https://www.ventrella.com/Clusters/ https://github.com/tom-mohr/particle-life-app

Source code in src/tolvera/vera/particle_life.py 
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@ti.data_oriented
class ParticleLife():
    """Particle Life model.

    The Particle Life model is a simple model of particle behaviour, where
    particles are either attracted or repelled by other particles, depending
    on their species. Popularised by Jeffrey Ventrella (Clusters), Tom Mohr
    and others:

    https://www.ventrella.com/Clusters/
    https://github.com/tom-mohr/particle-life-app

    """
    def __init__(self, tolvera, **kwargs) -> None:
        """Initialise the Particle Life model.

        'plife' stores the species rule matrix.

        Args:
            tolvera (Tolvera): A Tolvera instance.
            **kwargs: Keyword arguments (currently none).
        """
        self.tv = tolvera
        self.kwargs = kwargs
        self.CONSTS = CONSTS({
            "V": (ti.f32, 0.25),
        })
        self.tv.s.plife = {
            "state": {
                "attract": (ti.f32, -.5, .5),
                "radius": (ti.f32, 100., 300.0),
            },
            "shape": (self.tv.sn, self.tv.sn),
            "randomise": True,
        }
    @ti.kernel
    def step(self, particles: ti.template(), weight: ti.f32):
        """Step the Particle Life model.

        Args:
            particles (Particles.field): The particles to step.
            weight (ti.f32): The weight of the step.
        """
        for i in range(particles.shape[0]):
            if particles[i].active == 0.: continue
            p1 = particles[i]
            fx, fy = 0., 0.
            for j in range(particles.shape[0]):
                if particles[j].active == 0.: continue
                p2 = particles[j]
                s = self.tv.s.plife[p1.species, p2.species]
                dx = p1.pos[0] - p2.pos[0]
                dy = p1.pos[1] - p2.pos[1]
                d = ti.sqrt(dx*dx + dy*dy)
                if 0. < d and d < s.radius:
                    F = s.attract/d
                    fx += F*dx
                    fy += F*dy
            # particles[i].vel = (particles[i].vel + ti.Vector([fx, fy])) * self.CONSTS.V * weight
            # particles[i].pos += (particles[i].vel * p1.speed * p1.active * weight)
            particles[i].vel = (particles[i].vel + ti.Vector([fx, fy])) * self.CONSTS.V * weight * p1.speed * p1.active
            particles[i].pos += particles[i].vel
    def __call__(self, particles, weight: ti.f32 = 1.0):
        """Call the Particle Life model.

        Args:
            particles (Particles): The particles to step.
        """
        self.step(particles.field, weight)

__call__(particles, weight=1.0)

Call the Particle Life model.

Parameters:

Name Type Description Default
particles Particles

The particles to step.

 required
Source code in src/tolvera/vera/particle_life.py 
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def __call__(self, particles, weight: ti.f32 = 1.0):
    """Call the Particle Life model.

    Args:
        particles (Particles): The particles to step.
    """
    self.step(particles.field, weight)

__init__(tolvera, **kwargs)

Initialise the Particle Life model.

'plife' stores the species rule matrix.

Parameters:

Name Type Description Default
tolvera Tolvera

A Tolvera instance.

 required
**kwargs

Keyword arguments (currently none).

 {}
Source code in src/tolvera/vera/particle_life.py 
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def __init__(self, tolvera, **kwargs) -> None:
    """Initialise the Particle Life model.

    'plife' stores the species rule matrix.

    Args:
        tolvera (Tolvera): A Tolvera instance.
        **kwargs: Keyword arguments (currently none).
    """
    self.tv = tolvera
    self.kwargs = kwargs
    self.CONSTS = CONSTS({
        "V": (ti.f32, 0.25),
    })
    self.tv.s.plife = {
        "state": {
            "attract": (ti.f32, -.5, .5),
            "radius": (ti.f32, 100., 300.0),
        },
        "shape": (self.tv.sn, self.tv.sn),
        "randomise": True,
    }

step(particles, weight)

Step the Particle Life model.

Parameters:

Name Type Description Default
particles field

The particles to step.

 required
weight f32

The weight of the step.

 required
Source code in src/tolvera/vera/particle_life.py 
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@ti.kernel
def step(self, particles: ti.template(), weight: ti.f32):
    """Step the Particle Life model.

    Args:
        particles (Particles.field): The particles to step.
        weight (ti.f32): The weight of the step.
    """
    for i in range(particles.shape[0]):
        if particles[i].active == 0.: continue
        p1 = particles[i]
        fx, fy = 0., 0.
        for j in range(particles.shape[0]):
            if particles[j].active == 0.: continue
            p2 = particles[j]
            s = self.tv.s.plife[p1.species, p2.species]
            dx = p1.pos[0] - p2.pos[0]
            dy = p1.pos[1] - p2.pos[1]
            d = ti.sqrt(dx*dx + dy*dy)
            if 0. < d and d < s.radius:
                F = s.attract/d
                fx += F*dx
                fy += F*dy
        # particles[i].vel = (particles[i].vel + ti.Vector([fx, fy])) * self.CONSTS.V * weight
        # particles[i].pos += (particles[i].vel * p1.speed * p1.active * weight)
        particles[i].vel = (particles[i].vel + ti.Vector([fx, fy])) * self.CONSTS.V * weight * p1.speed * p1.active
        particles[i].pos += particles[i].vel