ndir.py

import plotly.figure_factory as ff
import plotly.graph_objects as go

import numpy as np

x,y = np.meshgrid(np.arange(-2, 2, .2),
                  np.arange(-2, 2, .25))
z = x*np.exp(-x**2 - y**2)
v, u = np.gradient(z, .2, .2)

# Create quiver figure# Create quiver figure
fig = ff.create_quiver(x, y, u, v,
                       scale=.25,
                       arrow_scale=.4,
                       name='quiver',
                       line_width=1)

# Add points to figure
fig.add_trace(go.Scatter(x=[-.7, .75], y=[0,0],
                    mode='markers',
                    marker_size=12,
                    name='points'))

fig.show()

import matplotlib.pyplot as plt
import numpy as np



fig, ax = plt.subplots()
q = ax.quiver(x, y, u, v)
ax.quiverkey(q, X=0.3, Y=1.1, U=10,
             label='Quiver key, length = 10', labelpos='E')

plt.show()