Permutation.inversions() : inversions() is a sympy Python library function that returns the number of inversions value of the permutation in the argument.
The inversion vector includes those elements whose value indicates the no. of elements in the permutation that are < it and lie on its right-hand side.
Syntax : Return : number of inversions value of the permutation in argument
Code #1 : inversions() Example
# Python code explaining # SymPy.Permutation.inversions()   # importing SymPy libraries from sympy.combinatorics.partitions import Partition from sympy.combinatorics.permutations import Permutation   # Using from # sympy.combinatorics.permutations.Permutation.inversions() method   # creating Permutation a = Permutation([[2, 0], [3, 1]])   b = Permutation([1, 3, 5, 4, 2, 0])     print ("Permutation a - inversions form : ", a.inversions()) print ("Permutation b - inversions form : ", b.inversions()) |
Output :
Permutation a – inversions form : 4
Permutation b – inversions form : 9
Code #2 : inversions() Example – 2D Permutation
# Python code explaining # SymPy.Permutation.inversions()   # importing SymPy libraries from sympy.combinatorics.partitions import Partition from sympy.combinatorics.permutations import Permutation   # Using from sympy.combinatorics.permutations.Permutation.inversions() method   # creating Permutation a = Permutation([[2, 4, 0],                  [3, 1, 2],                  [1, 5, 6]])     print ("Permutation a - inversions form : ", a.inversions()) |
Output :
Permutation a – inversions form : 10
