import numpy as np.py

import numpy as np
import matplotlib.pyplot as plt
Q = [(-3,0,-2), (3,0,20) ]

x1, y1 = -5, -5
x2, y2 = 5, 5
lres = 10	
m, n = lres * (y2-y1), lres * (x2-x1)
x, y = np.linspace(x1,x2,n), np.linspace(y1,y2,m)
x, y = np.meshgrid(x,y)
Ex = np.zeros((m,n)) 
Ey = np.zeros((m,n)) 

k = 9 * 10**9
for j in range(m):
	for i in range(n):
		xp, yp = x[j][i], y[j][i]
		for q in Q:
			deltaX = xp - q[0]
			deltaY = yp - q[1] 

			distance = (deltaX**2 + deltaY**2)**0.5

			E = (k*q[2])/(distance**2)	 
			Ex[j][i] += E*(deltaX/distance)
			Ey[j][i] += E*(deltaY/distance) 
			
fig, ax = plt.subplots()
ax.set_aspect('equal')
ax.scatter([q[0] for q in Q], [q[1] for q in Q], c = 'fuchsia', s = [abs(q[2])*50 for q in Q], zorder = 1)
for q in Q: ax.text(q[0]+0.1, q[1]-0.3, '{} Q'.format(q[2]), color = 'deepskyblue', zorder = 2)
ax.streamplot(x,y,Ex,Ey, linewidth = 1, density = 1.5, zorder = 0 , color = 'indigo')

plt.title('Electric Field - Sadra Yosefabadi - 402243114',color = 'deepskyblue')
plt.show()