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I want to create a three dimensional array with standard distance one in each direction, so that i receive, with x=10; y=10; z=10; 1000 cells, for example. In the next step, i want to assign an additional variable "E" to each cell where its worth consist of a gaussian distribution with mean 1 and variance 0,1.

I have already tried to create a multidimensional array using:

import numpy as np
x = np.array([[range(11)],[range(11)],[range(11)]],dtype=int)

Aswell as:

x,y,z = mgrid[0:11, 0:11, 0:11]

But i do not know if it is the kind of type i am looking for and how to add a variable to each cell of it.

I am pretty new to programming and python. As additional modules i want to use numpy, scipy and matplotlib.

Thanks for help!

Best regards.

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1  
Do you want to add a random variable drawn from a Gaussian distirbution? –  doctorlove Jul 31 '13 at 9:36
    
hstack for the extra column: stackoverflow.com/questions/8486294/… –  doctorlove Jul 31 '13 at 9:38
    
Yes, i want to assign a random variable from a gaussian distributin with mean 1 and variance 0.1 for each single cell. It would follow the gaussian density function, doesn't it? –  JayandB Jul 31 '13 at 10:00

1 Answer 1

up vote 0 down vote 
import numpy as np
E = np.random.normal(size=(1000, 1000, 1000)) * 0.1
print(E.shape)
# (1000, 1000, 1000)

print(E.var())
# 0.0100944667935

This creates a 3-dimensional array, whose elements are random variates sampled from a normal distribution (mean 0, variance 0.1).

I don't understand the first part of your question. Can you give a small concrete example of what values you want in that array?

share|improve this answer
    
Hi, thanks for this help. I want the values to be variable in size which means i want to put in a max worth for x,y and z axes. If you imagine it as a 3dimensional rubikscube with many little cubes in it, i want that every little cube has x=1 y=1 z=1 in axes lenght, so that a rubikscube with site length x=10 y=10 z=10 has 1000 of little cubes with site lenght x=1 y=1 z=1. For example "minicube" one has coordinates x=1 y=1 z=1 and minicube two has coordinates x=1 y=1 z=2, than minicube two would be next to minicube one in direction of z-axis. –  JayandB Jul 31 '13 at 10:42
    
Then is E what you are looking for? It has 1000 "little cubes" in each direction, and it is filled with random values. Remember, an array has no side length, so I don't understand how you wish to translate that aspect of your rubikscube model to a NumPy array. It would be very helpful if you can post a concrete small example of what the array should look like. –  unutbu Jul 31 '13 at 11:01
    
Hi i draw an example: s1.directupload.net/file/d/3333/gjgcxwgk_png.htm It shows the mincubes from which each should have a determined worth out of the gaussian distribution. –  JayandB Jul 31 '13 at 11:21
    
Okay, thanks for drawing. But now you have to show us what that means in terms of an array: np.array([[[...],[...],],...]). An array is not a minicube. Some attributes of a minicube, such as side length, have no analog in terms of a NumPy array. –  unutbu Jul 31 '13 at 11:48
    
Well, but i can define this minicubes by using vectors in every direction since numpy is building up the array from 0,0,0 in every direction isn't it so? In the case i would use vectors for further mathematics i could define x=1 y=1 z=1 for first and x=3, y=3, z=3 for a second point, so that numpy would automatically think i am taking the cell the vector or the vector difference is pointing to. Can python realize a 3 dimensional matrix with side length, distance between cells etc.? –  JayandB Jul 31 '13 at 13:40

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