#!/usr/bin/env python
# coding: utf-8

# ## Vector field animation
# 
# 
# 

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import k3d
import numpy as np
import time 

plot = k3d.plot()

Nx,Ny = 10,10

x = np.linspace(-1,1,Nx)
y = np.linspace(-2,2,Ny)

x,y = np.meshgrid(x,y)
z = np.zeros_like(x)

origins = np.vstack([x.flatten(),y.flatten(),z.flatten()]).T
vectors = 0.5*(np.vstack([np.zeros_like(x.flatten()),np.zeros_like(x.flatten()),np.ones_like(x.flatten())] )).T
phi0 = np.linspace(0,2*np.pi,vectors.shape[0])
labels = [str(i) for i in range(vectors.shape[0])]
vector_plot = k3d.vectors(origins.astype(np.float32), vectors.astype(np.float32))

plot += vector_plot
plot.display()


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plot.camera_auto_fit = False
plot.grid_auto_fit = False

for phi in np.linspace(0,2*np.pi,55):
    r = 0.1  
    v = vector_plot.vectors.copy()
    v[:,0] += r*np.cos(phi+phi0)
    v[:,1] += r*np.sin(phi+phi0)
    vector_plot.vectors = v
    time.sleep(0.05) # have to wait for real data update


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