perm_sign¶
full name: tenpy.tools.math.perm_sign
parent module:
tenpy.tools.math
type: function
-
tenpy.tools.math.
perm_sign
(p)[source]¶ Given a permutation p of numbers, returns its sign. (+1 or -1)
Assumes that all the elements are distinct, if not, you get crap.
Examples
>>> for p in itertools.permutations(range(3))]): ... print('{p!s}: {sign!s}'.format(p=p, sign=perm_sign(p))) (0, 1, 2): 1 (0, 2, 1): -1 (1, 0, 2): -1 (1, 2, 0): 1 (2, 0, 1): 1 (2, 1, 0): -1