Title: Permutations

1 Class methods

GSL::Permutation.new(n)
GSL::Permutation.alloc(n): These functions create a new permutation of size n. The permutation is not initialized and its elements are undefined. Use GSL::Permutation.calloc if you want to create a permutation which is initialized to the identity.
GSL::Permutation.calloc(n): This creates a new permutation of size n and initializes it to the identity.

GSL::Permutation#init(): This initializes the permutation to the identity, i.e. (0,1,2,...,n-1).
GSL::Permutation.memcpy(dest, src): This method copies the elements of the permutation src into the permutation dest. The two permutations must have the same size.
GSL::Permutation#clone: This creates a new permutation with the same elements of self.

GSL::Permutation#get(i): Returns the value of the i-th element of the permutation.
GSL::Permutation#swap(i, j): This exchanges the i-th and j-th elements of the permutation.

GSL::Permutation#size: Returns the size of the permutation.
GSL::Permutation#valid: This checks that the permutation self is valid. The n elements should contain each of the numbers 0 .. n-1 once and only once.
GSL::Permutation#valid?: This returns true if the permutation self is valid, and false otherwise.

GSL::Permutation#reverse: This reverses the elements of the permutation self.
GSL::Permutation#inverse: This computes the inverse of the permutation self, and returns as a new permutation.
GSL::Permutation#next: This method advances the permutation self to the next permutation in lexicographic order and returns GSL::SUCCESS. If no further permutations are available it returns GSL::FAILURE and leaves self unmodified. Starting with the identity permutation and repeatedly applying this function will iterate through all possible permutations of a given order.
GSL::Permutation#prev: This method steps backwards from the permutation self to the previous permutation in lexicographic order, returning GSL_SUCCESS. If no previous permutation is available it returns GSL_FAILURE and leaves self unmodified.