Point Charges Simulator.md

Point Charges Simulator

Basic program for simulating the motion of three point charges.

Example Graph

Config Dialog

point_charges.py

from Tkinter import *
import sys

import matplotlib as mpl
from mpl_toolkits.mplot3d import Axes3D
import numpy as np
import matplotlib.pyplot as plt

K =  8.9875517873681764 * (10 ** 9)

class Particle:
	def __init__(self):
		self.x = []
		self.y = []

	#Pushes position into vector (so it can be graphed with respect to time)
	def push_position(self):
		self.x.append(self.position[0])
		self.y.append(self.position[1])

	#Use the position of all of the particles to calculate the current particle's position
	def calc_velocity(self, particles, dt):
		#Start with empty net force
		net_force = [0,0]

		for particle in particles:
			if particle != self:
				r = np.subtract(self.position, particle.position)
				r_mag = np.linalg.norm(r)
				r_hat = np.divide(r, r_mag)

				magnitude = (K*particle.charge*self.charge)/(r_mag ** 2)
				force = np.multiply(magnitude, r_hat)
				
				net_force = np.add(net_force, force)
		acceleration = np.divide( net_force, self.mass)
		self.velocity = np.add( self.velocity, np.multiply( acceleration, dt) )
	def calc_position(self, dt):
		self.position = np.add(self.position,  np.multiply( self.velocity, dt) )

def step(particles, dt):
	for p in particles: p.push_position()
	for p in particles: p.calc_velocity(particles, dt)
	for p in particles: p.calc_position(dt)

def to_vector(str):
	vector = [0,0]
	components = str.split(',')
	for i in range(len(vector)):
		vector[i] = float(components[i])
	return vector
	
if __name__ == "__main__":
	#Create gui for configuring particles
	gui = Tk()
	gui.title("Particle Configuration")
	
	configs = []
	
	grid_row = 0
	def make_particle_config(particle_name, inital_position, initial_velocity, initial_mass, initial_charge):
		global grid_row
		config_frame = Frame(gui, borderwidth=5, relief=GROOVE)
		config_frame.grid(row=grid_row,padx=10, pady=10)
		grid_row = grid_row + 1
		
		Label(config_frame, text=particle_name).grid(row=0, column=0, sticky=W)
		
		Label(config_frame, text="Position (m):").grid(row=1, column=0)
		position_entry = Entry(config_frame)
		position_entry.grid(row=1, column=1)
		position_entry.insert(0, inital_position)
		
		Label(config_frame, text="Velocity (m/s):").grid(row=2, column=0)
		velocity_entry = Entry(config_frame)
		velocity_entry.grid(row=2, column=1)
		velocity_entry.insert(0,initial_velocity)
		
		Label(config_frame, text="Mass (kg):").grid(row=3, column=0)
		mass_entry = Entry(config_frame)
		mass_entry.grid(row=3, column=1)
		mass_entry.insert(0, initial_mass)
		
		Label(config_frame, text="Charge (C):").grid(row=4, column=0)
		charge_entry = Entry(config_frame)
		charge_entry.grid(row=4, column=1)
		charge_entry.insert(0, initial_charge)
		
		def get_particle():
			particle = Particle()
			particle.name = particle_name
			particle.position = to_vector(position_entry.get())
			particle.velocity = to_vector(velocity_entry.get())
			particle.mass = float(mass_entry.get())
			particle.charge = float(charge_entry.get())

			return particle
		
		configs.append(get_particle)
	
	make_particle_config("Particle A", "0,0", "0,0", "1.67262178e-31", "1.6021766e-19")
	make_particle_config("Particle B", "1,0", "0,10", "9.10938291e-31", "-1.6021766e-19")
	make_particle_config("Particle C", "-1,0", "0,-10", "9.10938291e-31", "-1.6021766e-19")
	
	settings_frame = Frame(gui)
	settings_frame.grid(row=grid_row,padx=10, pady=10)

	#Time Step Entry
	Label(settings_frame, text="Time Step (sec):").grid(row=0, column=0)
	timestep_entry = Entry(settings_frame)
	timestep_entry.grid(row=0, column=1)
	timestep_entry.insert(0, "0.005")

	#Seconds Entry
	Label(settings_frame, text="Seconds to Simulate (sec):").grid(row=0, column=2)
	seconds_entry = Entry(settings_frame)
	seconds_entry.grid(row=0, column=3)
	seconds_entry.insert(0, "1")

	#Create run menu
	gui.option_add('*tearOff', FALSE)
	menubar = Menu(gui)
	gui['menu'] = menubar
	
	#Plot graph using matplotlib
	def plot_graph():
		fig = plt.figure()
		ax = fig.gca(projection='3d')

		ax.set_xlabel('Time (sec)')
		ax.set_ylabel('X (m)')
		ax.set_zlabel('Y (m)')

		particles = [get_particle() for get_particle in configs]

		delta_time = float(timestep_entry.get())
		total_seconds = float(seconds_entry.get())

		current_time = 0.0
		time_steps = []
		while current_time < total_seconds:
			time_steps.append(current_time)
			current_time += delta_time
			step(particles, delta_time)

		for particle in particles:
			ax.plot(time_steps, particle.x, particle.y, label=particle.name)
		ax.legend()

		plt.show()
		
	'''def animation_2d():
		DEFAULTSCREENSIZE = (800, 600)
		import pygame
		pygame.init()
		screen = pygame.display.set_mode(DEFAULTSCREENSIZE, pygame.DOUBLEBUF)
		pygame.quit()'''
		
	menu_run = Menu(menubar)
	menubar.add_cascade(menu=menu_run, label='Run')
	menu_run.add_command(label='Graph Pathways', command=plot_graph)
	#menu_run.add_command(label='2D Animation', command=animation_2d)
	
	gui.mainloop()