Homework 2. Socket open [Feb 4, 2003] Qn I. Consider the following "artificial" planning domain, which contains the (artificial) operators described below: operator O1 prec: P Eff: R, ~S operator O2 prec: Q Eff: S operator O3 prec: P Eff: M operator O4 prec: R,S Eff: P,Q,R,S operator O5 prec: R,S Eff: P The initial state is {P,Q} and the desired goals are {P,Q,R,S} I.a Show first level of the search tree generated by progression search. Also show the branch that leads to the goal state I.b Show first level of the search tree generated by regression search. Also show the branch that leads to the initial state I.c. Assuming that we do open condition P is considered first, show the *complete* set of partial plans generated by a POP planner to resolve this flaw. Also show the entire branch that leads to a solution plan (with annotations so I know you understand POP algorithm). **Added [Feb 9, 2003] I.D Draw the planning graph for this problem--without mutexes I.E. Mark the mutexes on the planning graph I. F. For the regression search nodes in I.b. compute their heuristic value using I.D and I.E, and using Set-level and Sum heuristics (in each case). II. Consider the following simple problem Operator A eff: If P then Q If R then W Operator B prec: M eff: W Init state: P,M Goals: Q,W Show the complete first level search tree for regression search. Explain branches lead to solution and which don't. Explain what is the new requirements on regression based child node generation given that A has conditional effects. III. Consider the following plan: A1------A2 I G B1------B2 G requires P and Q (which are the top level goals) Assume that A2 and B2 both give P and Q as effects. A2 requires R. A1 gives R, but deletes Q B2 requires S. B1 gives S, but delete P A1 and B1 have no preconditions. III.a. Is this partial plan correct (i.e. will every topological sort of this plan execute to give the solution state?) III.b. Can you give causal links for this plan such that all causal links are threat-free (hint: consider A2--P-->G etc.) III.c. If the answer to b was no, what is the lesson here? Compare it to the discussion of causal link semantics that we did in the class. IV. Run your register swapping problem (from homework 1) on AltAlt (code for which was provided to you by Romeo Sanchez) =====