Coverage for moptipy / operators / permutations / __init__.py: 100%

1""" 

2Search operators for permutations with repetitions. 

3 

4These operators can be used in conjunction with the space 

5:class:`~moptipy.spaces.permutations.Permutations`. 

6 

7- Module :mod:`~moptipy.operators.permutations.op0_shuffle` provides a nullary 

8 operator sampling an entirely random permutation. 

9- Module :mod:`~moptipy.operators.permutations.op1_insert1` provides a unary 

10 operator that extracts one element and inserts it elsewhere. 

11- Module :mod:`~moptipy.operators.permutations.op1_swap2` provides a unary 

12 operator which swaps exactly two different elements of a permutation. 

13- Module :mod:`~moptipy.operators.permutations.op1_swapn` provides a unary 

14 operator which tries to find a cyclic move whose length would be 

15 approximately binomially distributed, i.e., which may swap two elements with 

16 probability 0.5, three elements with probability 0.25, 4 elements with 

17 probability 0.125, and so on. It does so by performing a sequence of swaps 

18 but does not check whether one swap undoes a previous one. 

19- Module :mod:`~moptipy.operators.permutations.op1_swap_exactly_n` offers a 

20 unary operator with a step size (see 

21 :class:`~moptipy.api.operators.Op1WithStepSize`). A step size of `0.0` means 

22 that it will swap two elements, a step size of `1.0` means that it tries to 

23 perform the largest-possible modification. If it is applied to permutations 

24 where each element occurs once, this means that all elements change their 

25 position. If applied to permutations with repetitions, things are more 

26 complex and some moves may be impossible, in which case a best effort is 

27 attempted. 

28- Module :mod:`~moptipy.operators.permutations.op1_swap_try_n` is similar to 

29 the operator from :mod:`~moptipy.operators.permutations.op1_swap_exactly_n`, 

30 but invests less effort into reaching the prescribed number of modifications 

31 exactly. Instead, it will accept making only fewer swaps more easily. 

32- Module :mod:`~moptipy.operators.permutations.op2_gap` offers an operator 

33 that tries to build a new permutation by appending not-yet-appended elements 

34 from both input permutations, alternating between them randomly. 

35- Module :mod:`~moptipy.operators.permutations.op2_ox2` implements a slightly 

36 modified version of the order-based crossover operator for permutations. 

37"""