unknown Initial ITS Start location: [1] Program variables: c x 0: [1] -> [2] : x'=nondet, T, cost: 1 1: [2] -> [3] : c'=nondet1, T, cost: 1 2: [3] -> [5] : -2+c >= 0, cost: 1 9: [3] -> [4] : -2+c < 0, cost: 1 3: [5] -> [6] : c+x >= 0, cost: 1 7: [5] -> [9] : c+x < 0, cost: 1 4: [6] -> [7] : x'=-c+x, T, cost: 1 5: [7] -> [8] : c'=1+c, T, cost: 1 6: [8] -> [5] : T, cost: 1 8: [9] -> [4] : T, cost: 1 Chained Linear Paths Start location: [1] Program variables: c x 10: [1] -> [3] : c'=nondet1, x'=nondet, T, cost: 1 2: [3] -> [5] : -2+c >= 0, cost: 1 9: [3] -> [4] : -2+c < 0, cost: 1 12: [5] -> [4] : c+x < 0, cost: 1 14: [5] -> [5] : c'=1+c, x'=-c+x, c+x >= 0, cost: 1 Eliminating location [2] by chaining: Applied chaining First rule: [1] -> [2] : x'=nondet, T, cost: 1 Second rule: [2] -> [3] : c'=nondet1, T, cost: 1 New rule: [1] -> [3] : c'=nondet1, x'=nondet, T, cost: 1 Applied deletion Removed the following rules: 0 1 Eliminating location [6] by chaining: Applied chaining First rule: [5] -> [6] : c+x >= 0, cost: 1 Second rule: [6] -> [7] : x'=-c+x, T, cost: 1 New rule: [5] -> [7] : x'=-c+x, c+x >= 0, cost: 1 Applied deletion Removed the following rules: 3 4 Eliminating location [9] by chaining: Applied chaining First rule: [5] -> [9] : c+x < 0, cost: 1 Second rule: [9] -> [4] : T, cost: 1 New rule: [5] -> [4] : c+x < 0, cost: 1 Applied deletion Removed the following rules: 7 8 Eliminating location [7] by chaining: Applied chaining First rule: [5] -> [7] : x'=-c+x, c+x >= 0, cost: 1 Second rule: [7] -> [8] : c'=1+c, T, cost: 1 New rule: [5] -> [8] : c'=1+c, x'=-c+x, c+x >= 0, cost: 1 Applied deletion Removed the following rules: 5 11 Eliminating location [8] by chaining: Applied chaining First rule: [5] -> [8] : c'=1+c, x'=-c+x, c+x >= 0, cost: 1 Second rule: [8] -> [5] : T, cost: 1 New rule: [5] -> [5] : c'=1+c, x'=-c+x, c+x >= 0, cost: 1 Applied deletion Removed the following rules: 6 13 Step with 10 Trace 10[T] Blocked [{}, {}] Step with 2 Trace 10[T], 2[(-2+c >= 0)] Blocked [{}, {}, {}] Step with 12 Trace 10[T], 2[(-2+c >= 0)], 12[(c+x < 0)] Blocked [{}, {}, {}, {}] Backtrack Trace 10[T], 2[(-2+c >= 0)] Blocked [{}, {}, {12[T]}] Step with 14 Trace 10[T], 2[(-2+c >= 0)], 14[(c+x >= 0)] Blocked [{}, {}, {12[T]}, {}] Accelerate Start location: [1] Program variables: c x 10: [1] -> [3] : c'=nondet1, x'=nondet, T, cost: 1 2: [3] -> [5] : -2+c >= 0, cost: 1 9: [3] -> [4] : -2+c < 0, cost: 1 12: [5] -> [4] : c+x < 0, cost: 1 14: [5] -> [5] : c'=1+c, x'=-c+x, c+x >= 0, cost: 1 15: [5] -> [5] : c'=n+c, x'=-n*c-1/2*n^2+1/2*n+x, (-1+n >= 0 /\ -3/2-1/2*(-1+n)^2-(-1+n)*c+3/2*n+c+x >= 0 /\ c+x >= 0), cost: 1 Loop Acceleration Original rule: [5] -> [5] : c'=1+c, x'=-c+x, (c+x >= 0), cost: 1 New rule: [5] -> [5] : c'=n+c, x'=-n*c-1/2*n^2+1/2*n+x, (-1+n >= 0 /\ -3/2-1/2*(-1+n)^2-(-1+n)*c+3/2*n+c+x >= 0 /\ c+x >= 0), cost: 1 c+x >= 0 [0]: eventual decrease yields (-3/2-1/2*(-1+n)^2-(-1+n)*c+3/2*n+c+x >= 0 /\ c+x >= 0) Replacement map: {c+x >= 0 -> (-3/2-1/2*(-1+n)^2-(-1+n)*c+3/2*n+c+x >= 0 /\ c+x >= 0)} Trace 10[T], 2[(-2+c >= 0)], 15[(-1+n >= 0 /\ -3/2-1/2*(-1+n)^2-(-1+n)*c+3/2*n+c+x >= 0 /\ c+x >= 0)] Blocked [{}, {}, {12[T]}, {14[T], 15[T]}] Step with 12 Trace 10[T], 2[(-2+c >= 0)], 15[(-1+n >= 0 /\ -3/2-1/2*(-1+n)^2-(-1+n)*c+3/2*n+c+x >= 0 /\ c+x >= 0)], 12[(c+x < 0)] Blocked [{}, {}, {12[T]}, {14[T], 15[T]}, {}] Backtrack Trace 10[T], 2[(-2+c >= 0)], 15[(-1+n >= 0 /\ -3/2-1/2*(-1+n)^2-(-1+n)*c+3/2*n+c+x >= 0 /\ c+x >= 0)] Blocked [{}, {}, {12[T]}, {12[T], 14[T], 15[T]}] Backtrack Trace 10[T], 2[(-2+c >= 0)] Blocked [{}, {}, {12[T], 15[T]}] Step with 14 Trace 10[T], 2[(-2+c >= 0)], 14[(c+x >= 0)] Blocked [{}, {}, {12[T], 15[T]}, {}] Covered Trace 10[T], 2[(-2+c >= 0)] Blocked [{}, {}, {12[T], 14[T], 15[T]}] Backtrack Trace 10[T] Blocked [{}, {2[T]}] Step with 9 Trace 10[T], 9[(-2+c < 0)] Blocked [{}, {2[T]}, {}] Backtrack Trace 10[T] Blocked [{}, {2[T], 9[T]}] Backtrack Trace Blocked [{10[T]}] Accept unknown Build SHA: a05f16bf13df659c382799650051f91bf6828c7b