Reputation: 23
I'm trying to create a simple cube following this code:
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
import numpy as np
# Create axis
axes = [5,5,5]
# Create Data
data = np.ones(axes, dtype=np.bool)
# Controll Tranperency
alpha = 0.9
# Control colour RGBA colour
colors = np.empty(axes + [4], dtype=np.float32)
colors[0] = [1, 0, 0, alpha] # red
colors[1] = [0, 1, 0, alpha] # green
colors[2] = [0, 0, 1, alpha] # blue
colors[3] = [1, 1, 0, alpha] # yellow
colors[4] = [1, 1, 1, alpha] # grey
# Plot figure
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
# Voxels are used for customizations of sizes, positions, and colors.
ax.voxels(data, facecolors=colors, edgecolors='grey')
plt.show()
It works well. But when I change axes = [10, 10, 10]
, here is the code:
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
import numpy as np
# Create axis
axes = [10, 10, 10]
# Create Data
data = np.ones(axes, dtype=np.bool)
# Controll Tranperency
alpha = 0.9
# Control colour RGBA colour
colors = np.empty(axes + [4], dtype=np.float32)
colors[0] = [1, 0, 0, alpha] # red
colors[1] = [0, 1, 0, alpha] # green
colors[2] = [0, 0, 1, alpha] # blue
colors[3] = [1, 1, 0, alpha] # yellow
colors[4] = [1, 1, 1, alpha] # grey
# Plot figure
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
# Voxels are used for customizations of sizes, positions, and colors.
ax.voxels(data, facecolors=colors, edgecolors='grey')
plt.show()
sometimes it works, sometimes it doesn't, and throw the error: ValueError: Invalid RGBA argument: 4.435719e+27
. The same error when I remove dtype in data = np.ones(axes, type=np.bool)
. Now I am unable to debug the Invalid RGBA argument
because I don't understand what is causing the error. I read this, but it seems that error about invalid shape, not invalid value.
Why can this error happen? How can I fix it? Thank you very much.
Upvotes: 2
Views: 4527
Reputation: 11992
You're getting this error because np.empty
created basically randomly filled arrays (sometimes uses empty memory space, which is why it sometimes will work for you). This isn't a problem with axes = [5, 5, 5]
because you're filling out proper RGBA values when you assign colors, but with bigger axes it wont work as well.
Look at the result of printing colors
when axes is [5, 5, 5]
vs. the times it doesn't work for you with [10, 10, 10]
To fix: use np.zeros
instead of np.empty
to make sure zeros is what you get for missing values:
axes = [10, 10, 10]
colors = np.zeros(axes + [4], dtype=np.float32)
Upvotes: 3