def get_adjacency_distance(self, other):
        """
        Computes the adjacency distance between two permutations.

        This metric counts the number of times a pair i,j of jobs is
        adjacent in both p and p'. If n_adj is this quantity then
        the adjacency distance is n - n_adj - 1 [1]

        [1] Reeves, Colin R. Landscapes, Operators and Heuristic search, Annals
        of Operational Research, 86, pp 473-490. (1999)


        Examples
        ========

        >>> from sympy.combinatorics.permutations import Permutation
        >>> p = Permutation([0, 3, 1, 2, 4])
        >>> q = Permutation.josephus(4, 5, 2)
        >>> p.get_adjacency_distance(q)
        3
        >>> r = Permutation([0, 2, 1, 4, 3])
        >>> p.get_adjacency_distance(r)
        4

        See Also
        ========

        get_precedence_matrix, get_precedence_distance, get_adjacency_matrix
        """
        if self.size != other.size:
            raise ValueError("The permutations must be of the same size.")
        self_adj_mat = self.get_adjacency_matrix()
        other_adj_mat = other.get_adjacency_matrix()
        n_adj = 0
        for i in range(self.size):
            for j in range(self.size):
                if i == j:
                    continue
                if self_adj_mat[i, j] * other_adj_mat[i, j] == 1:
                    n_adj += 1
        d = self.size - 1 - n_adj
        return d
dataset/ETHPy150Open sympy/sympy/sympy/combinatorics/permutations.py/Permutation.get_adjacency_distance/swapped operands of `-`