Extracting a Relaxed soln When a layer containing all of the goals is reached, FF searches backwards for a plan The first possible achiever found is always used to achieve each goal This maximizes the possibility for exploiting actions in the relaxed plan The relaxed plan might contain many actions happening concurrently at a layer The number of actions in the relaxed plan is an estimate of the true cost of achieving the goals Distance Estimate Extracted From A Relaxed Plan Graph Current: In(A), Closed Goal: In(B) In(a) noop In(A) In(A) noop Closed noop Closed Move In B) Opened Closed Op noop Opened noo Close Ope Layer 3 Layers correspond to successive time points layers indicate minimum time to achieve goalsExtracting a Relaxed Soln ƒ When a layer containing all of the goals is reached, FF searches backwards for a plan. ƒ The first possible achiever found is always used to achieve each goal. ƒ This maximizes the possibility for exploiting actions in the relaxed plan. ƒ The relaxed plan might contain many actions happening concurrently at a layer. ƒ The number of actions in the relaxed plan is an estimate of the true cost of achieving the goals. Distance Estimate Extracted From A Relaxed Plan Graph ƒ Layers correspond to successive time points, ƒ # layers indicate minimum time to achieve goals. In(A) Closed Layer 1 ƒ Current: In(A), Closed Goal: In(B) Open noop noop In(A) Closed Opened Layer 2 In(B) noop noop Move Open noop Close In(A) Closed Opened Layer 3