unknown Initial ITS Start location: [1] Program variables: x 0: [1] -> [2] : x'=0, T, cost: 1 1: [2] -> [3] : x >= 0, cost: 1 4: [2] -> [5] : x < 0, cost: 1 2: [3] -> [4] : x'=-1+x, T, cost: 1 3: [4] -> [2] : T, cost: 1 Chained Linear Paths Start location: [1] Program variables: x 0: [1] -> [2] : x'=0, T, cost: 1 4: [2] -> [5] : x < 0, cost: 1 6: [2] -> [2] : x'=-1+x, x >= 0, cost: 1 Eliminating location [3] by chaining: Applied chaining First rule: [2] -> [3] : x >= 0, cost: 1 Second rule: [3] -> [4] : x'=-1+x, T, cost: 1 New rule: [2] -> [4] : x'=-1+x, x >= 0, cost: 1 Applied deletion Removed the following rules: 1 2 Eliminating location [4] by chaining: Applied chaining First rule: [2] -> [4] : x'=-1+x, x >= 0, cost: 1 Second rule: [4] -> [2] : T, cost: 1 New rule: [2] -> [2] : x'=-1+x, x >= 0, cost: 1 Applied deletion Removed the following rules: 3 5 Step with 0 Trace 0[T] Blocked [{}, {}] Step with 6 Trace 0[T], 6[(x >= 0)] Blocked [{}, {4[T]}, {}] Accelerate Start location: [1] Program variables: x 0: [1] -> [2] : x'=0, T, cost: 1 4: [2] -> [5] : x < 0, cost: 1 6: [2] -> [2] : x'=-1+x, x >= 0, cost: 1 7: [2] -> [2] : x'=-n+x, (1-n+x >= 0 /\ -1+n >= 0), cost: 1 Loop Acceleration Original rule: [2] -> [2] : x'=-1+x, (x >= 0), cost: 1 New rule: [2] -> [2] : x'=-n+x, (1-n+x >= 0 /\ -1+n >= 0), cost: 1 x >= 0 [0]: montonic decrease yields 1-n+x >= 0 x >= 0 [1]: eventual increase yields (1 <= 0 /\ x >= 0) Replacement map: {x >= 0 -> 1-n+x >= 0} Trace 0[T], 7[(1-n+x >= 0 /\ -1+n >= 0)] Blocked [{}, {4[T]}, {6[T], 7[T]}] Step with 4 Trace 0[T], 7[(1-n+x >= 0 /\ -1+n >= 0)], 4[(x < 0)] Blocked [{}, {4[T]}, {6[T], 7[T]}, {}] Backtrack Trace 0[T], 7[(1-n+x >= 0 /\ -1+n >= 0)] Blocked [{}, {4[T]}, {4[T], 6[T], 7[T]}] Backtrack Trace 0[T] Blocked [{}, {4[T], 7[T]}] Step with 6 Trace 0[T], 6[(x >= 0)] Blocked [{}, {4[T], 7[T]}, {}] Covered Trace 0[T] Blocked [{}, {4[T], 6[T], 7[T]}] Backtrack Trace Blocked [{0[T]}] Accept unknown Build SHA: a05f16bf13df659c382799650051f91bf6828c7b