Hi,
How can I define in numpy a matrix that uses operations modulo 2?
For example:
0 0 1 0 1 0
1 1 + 0 1 = 1 0
Thanks!
+1
A:
You could subclass numpy.ndarray and override the __add__ method, but I think it would be far simpler to just be explicit. For example:
import numpy as np
x = np.array([[0,0],[1,1]])
y = np.array([[1,0],[0,1]])
print (x + y) % 2
Which yields:
array([[1, 0],
[1, 0]])
Joe Kington
2010-09-15 18:06:35
I also need the modular addition when multiplying two matrices
Yassin
2010-09-15 18:26:38
@Yassin - Then just do `(x * y) % 2`. Kenny's solution is the way to go, though... I tend to forget that xor and the like exist! It's a cleaner way to do what you want.
Joe Kington
2010-09-15 18:32:45
+4
A:
This operation is called "xor".
>>> import numpy
>>> x = numpy.array([[0,0],[1,1]])
>>> y = numpy.array([[1,0],[0,1]])
>>> x ^ y
array([[1, 0],
[1, 0]])
BTW, multiplication modulo 2 can be done with "and".
>>> x & y
array([[0, 0],
[0, 1]])
KennyTM
2010-09-15 18:28:33