Compatibility Between Sage And Numpy

Here are two lines of code for the purpose of generating a random permutation of size 4: from numpy import random t = random.permutation(4) This can be executed in Python, but not

Solution 1:

To escape Sage's preparser, you can also append the letter r (for "raw") to numerical input.

from numpy importrandomt= random.permutation(4r)

The advantage of 4r over int(4) is that 4r bypasses the preparser, while int(4) is preparsed as int(Integer(4)) so that the Python integer is transformed into a Sage integer and then transformed back into a Python integer.

In the same way, 1.5r will give you a pure Python float rather than a Sage "real number".

Solution 2:

The reason this doesn't work in Sage is that Sage preparses its input, turning "4" from a Python int to a Sage Integer. In Sage, this will work:

from numpy importrandomt= random.permutation(int(4))

Or you can turn the preparser off:

preparser(False)
t = random.permutation(4)