How to plot a multivariate function in Python?

Question

Plotting a single variable function in Python is pretty straightforward with matplotlib. But I'm trying to add a third axis to the scatter plot so I can visualize my multivariate model.

Here's an example snippet, with 30 outputs:

import numpy as np
np.random.seed(2)
## generate a random data set
x = np.random.randn(30, 2)
x[:, 1] = x[:, 1] * 100
y = 11*x[:,0] + 3.4*x[:,1] - 4 + np.random.randn(30) ##the model

If this was just a single variable model I'd probably use something like this to generate a plot & line of best fit:

%pylab inline
import matplotlib.pyplot as pl 
pl.scatter(x_train, y_train)
pl.plot(x_train, ols.predict(x_train))
pl.xlabel('x')
pl.ylabel('y')

What's the equivalent for multivariate visualization?

@BhargavRao Ha! I need these for life! Trying to expand my toolset. But yeah, that's one possible application. There are so many more. — samthebrand
– samthebrand, Commented May 19, 2015 at 21:09
also use %matplotlib notebook and get interactive graphs in the browser (assuming this is IPython notebook, use IPython > 3.0, mpl > 1.4) — tacaswell
– tacaswell, Commented May 20, 2015 at 0:27

Joe Kington · Accepted Answer · 2015-05-19 23:14:03Z

7

The most common approach is to vary the color and/or size of the scatter symbols. For example:

import numpy as np
import matplotlib.pyplot as plt
np.random.seed(2)

## generate a random data set
x, y = np.random.randn(2, 30)
y *= 100
z = 11*x + 3.4*y - 4 + np.random.randn(30) ##the model

fig, ax = plt.subplots()
scat = ax.scatter(x, y, c=z, s=200, marker='o')
fig.colorbar(scat)

plt.show()

enter image description here

answered May 19, 2015 at 23:14

Joe Kington

287k73 gold badges621 silver badges474 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

yalei du · Accepted Answer · 2015-05-20 01:33:40Z

6

Is this what you want?

3dplot](![enter image description here )

Source: http://nbviewer.ipython.org/urls/s3.amazonaws.com/datarobotblog/notebooks/multiple_regression_in_python.ipynb

answered May 20, 2015 at 1:33

yalei du

7657 silver badges13 bronze badges

1 Comment

Ralph Clausen Over a year ago

The provided URL is not working. Is there any other way to avail it?

Ami Tavory · Accepted Answer · 2015-05-19 21:12:22Z

4

You could use mplot3d. For a scatter plot, you can use something like

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.scatter(xs, ys, zs)

answered May 19, 2015 at 21:12

Ami Tavory

76.7k13 gold badges152 silver badges196 bronze badges

1 Comment

kztd Over a year ago

from mpl_toolkits.mplot3d import Axes3D makes it work

Collectives™ on Stack Overflow

How to plot a multivariate function in Python?

3 Answers 3

Comments

1 Comment

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related