genesis: Particle initialisation

In particles: A Graph Based Particle Simulator Based on D3-Force

Particle initialisation

Description

These functions are passed to the simulation and defines how the position and velocity of the particles are initiated. The default is to lay out the nodes in a phyllotactic arrangement (think sunflower seeds) and with no velocity, which is also the default in d3-force.

Usage

phyllotactic_genesis(radius = 10, angle = pi * (3 - sqrt(5)))

predefined_genesis(x, y, x_vel = 0, y_vel = 0)

bigbang_genesis(vel_min = 0, vel_max = 1)

aquarium_genesis(width = 10, height = 10, vel_min = 0, vel_max = 1)

petridish_genesis(max_radius = 10, vel_min = 0, vel_max = 1)

Arguments

radius	The radius modifier (will be multiplied by the square root of the index of the particle)
angle	The angular difference between two adjacent particles
x, y	The columns holding (or value of) the position coordinates
x_vel, y_vel	The columns holding (or value of) the velocity verlets
vel_min, vel_max	The bounds of the uniformly distributed velocities
width, height	The size of the rectangle holding the particles
max_radius	The size of the disc.

Value

A function that takes the particle graph and returns a list with a position and velocity element, each holding a matrix with two columns and a row for each particle giving the x and y position and velocity respectively.

Functions

• phyllotactic_genesis(): Initiates particles in a phyllotactic arrangement with zero velocity

• predefined_genesis(): Uses information from the node data to set position and velocity.

• bigbang_genesis(): Initiates particles at center position and a random velocity

• aquarium_genesis(): Places particles randomly in a rectangle and gives them a random velocity

• petridish_genesis(): Places particles randomly on a disc and gives them a random velocity

Examples

# A contrieved example
graph <- tidygraph::create_notable('bull')
genesis <- phyllotactic_genesis()
genesis(graph)

# Usually used as an argument to simulate
graph |>
  simulate(setup = phyllotactic_genesis())

particles documentation built on April 3, 2025, 7:21 p.m.