Heuristic Search for Planning with Different Forced Goal-Ordering Constraints

Algorithm 2

𝑀𝑜𝑣𝑒_𝑎ℎ𝑒𝑎𝑑(𝐿,𝑔,𝐿^′).

Input: Achieved goal sequence list 𝐿. Goal 𝑔 whose achievement

sequence needs to be moved ahead.

Output: New goal achievement sequence list 𝐿^′

01 bool 𝑠𝑢𝑐𝑐𝑒𝑠𝑠_𝑚𝑜𝑣𝑒𝑑=false, 𝑛𝑢𝑚←𝐿.size();

02 for   𝑖=𝑛𝑢𝑚:1

03       𝐿^′←∅;

04       for  (𝑘=1;𝑘⩽𝑖−1;𝑘++)

05        𝑠𝑡𝑎𝑡𝑒_𝑜𝑝_𝑝𝑎𝑖𝑟←𝐿[𝑘];

06       𝐿^′.push_back(𝑠𝑡𝑎𝑡𝑒_𝑜𝑝_𝑝𝑎𝑖𝑟);

07       𝑠₁←𝐿[𝑖].𝑠;

08       bool ℎ𝑎𝑣𝑒_𝑜𝑝=false;

09    𝑂_𝑔(𝑠₁)={𝑂¹_𝑔(𝑠₁),𝑂²_𝑔(𝑠₁),…,𝑂^𝑚_𝑔(𝑠₁)} is the available GAO

          set of 𝑔 in 𝑠₁. For ∀𝑜,𝑜^′∈ 𝑂^𝑛_𝑔(𝑠₁), there is 𝑜≅𝑜^′(1⩽𝑛⩽𝑚).

          The GAO in set 𝑂^𝑛1_𝑔(𝑠₁) has the smaller excludable GAO 

           set than that of in 𝑂^𝑛2_𝑔(𝑠₁) if there is 1⩽𝑛₁<𝑛₂⩽𝑚;

10        for   𝑙=1:𝑚

11          select an available GAO 𝑜^′_𝑔 from 𝑂^𝑙_𝑔(𝑠₁);

12          𝑠₂=𝑟𝑒𝑠𝑢𝑙𝑡(𝑠₁,𝜋_𝑜′𝑔)

13          if  (∃¬𝑔^′′∈𝑠₂, 𝑔^′′ has no available GAO in 𝑠₂)

14           continue;

15          else

16           ℎ𝑎𝑣𝑒_𝑜𝑝=true;

17           break;

18       if(ℎ𝑎𝑣𝑒_𝑜𝑝==true)

19       𝐿^′.push_back((𝑠₂,𝑜^′_𝑔,𝑠₁));

20       bool 𝑖𝑠_𝑏𝑟𝑒𝑎𝑘=false;

21        for   𝑗=𝑖∶𝑛𝑢𝑚

22         𝑜←𝐿[𝑗].𝑜;

23         if(𝑜 or its equivalent GAO 𝑜^′ is available in 𝑠₂)

24          𝑡𝑒𝑚_𝑜←𝑜 or 𝑡𝑒𝑚_𝑜←𝑜^′;

25          𝑠^′=𝑠₂;

26          𝑠₂=𝑟𝑒𝑠𝑢𝑙𝑡(𝑠^′,𝜋_{𝑡𝑒𝑚_𝑜});

27         𝐿^′.push_back((𝑠₂,𝑡𝑒𝑚_𝑜,𝑠^′));

28         else

29          𝑖𝑠_𝑏𝑟𝑒𝑎𝑘=true;

30          break;

31        if(𝑖𝑠_𝑏𝑟𝑒𝑎𝑘==false)

32       𝑠𝑢𝑐𝑐𝑒𝑠𝑠_𝑚𝑜𝑣𝑒𝑑=true;

33       return 𝑠𝑢𝑐𝑐𝑒𝑠𝑠_𝑚𝑜𝑣𝑒𝑑;

34      else

35       continue;

36   return 𝑠𝑢𝑐𝑐𝑒𝑠𝑠_𝑚𝑜𝑣𝑒𝑑;