unknown Initial ITS Start location: l4 Program variables: x^0 y^0 0: l0 -> l1 : x^0'=x^post1, y^0'=y^post1, (1+x^post1-x^0 == 0 /\ y^0 <= 0 /\ -1+y^post1-y^0 == 0), cost: 1 1: l0 -> l2 : x^0'=x^post2, y^0'=y^post2, (1-y^0 <= 0 /\ 1+y^post2-y^0 == 0 /\ x^0-x^post2 == 0), cost: 1 4: l1 -> l0 : x^0'=x^post5, y^0'=y^post5, (1-x^0 <= 0 /\ y^post5-x^0 == 0 /\ x^0-x^post5 == 0), cost: 1 2: l2 -> l0 : x^0'=x^post3, y^0'=y^post3, (y^0-y^post3 == 0 /\ x^0-x^post3 == 0), cost: 1 3: l3 -> l1 : x^0'=x^post4, y^0'=y^post4, (-y^post4+y^0 == 0 /\ -x^post4+x^0 == 0), cost: 1 5: l4 -> l3 : x^0'=x^post6, y^0'=y^post6, (x^0-x^post6 == 0 /\ y^0-y^post6 == 0), cost: 1 Chained Linear Paths Start location: l4 Program variables: x^0 y^0 0: l0 -> l1 : x^0'=x^post1, y^0'=y^post1, (1+x^post1-x^0 == 0 /\ y^0 <= 0 /\ -1+y^post1-y^0 == 0), cost: 1 7: l0 -> l0 : x^0'=x^post3, y^0'=y^post3, (-x^post3+x^post2 == 0 /\ 1-y^0 <= 0 /\ y^post2-y^post3 == 0 /\ 1+y^post2-y^0 == 0 /\ x^0-x^post2 == 0), cost: 1 4: l1 -> l0 : x^0'=x^post5, y^0'=y^post5, (1-x^0 <= 0 /\ y^post5-x^0 == 0 /\ x^0-x^post5 == 0), cost: 1 6: l4 -> l1 : x^0'=x^post4, y^0'=y^post4, (x^0-x^post6 == 0 /\ -x^post4+x^post6 == 0 /\ y^0-y^post6 == 0 /\ -y^post4+y^post6 == 0), cost: 1 Eliminating location l3 by chaining: Applied chaining First rule: l4 -> l3 : x^0'=x^post6, y^0'=y^post6, (x^0-x^post6 == 0 /\ y^0-y^post6 == 0), cost: 1 Second rule: l3 -> l1 : x^0'=x^post4, y^0'=y^post4, (-y^post4+y^0 == 0 /\ -x^post4+x^0 == 0), cost: 1 New rule: l4 -> l1 : x^0'=x^post4, y^0'=y^post4, (x^0-x^post6 == 0 /\ -x^post4+x^post6 == 0 /\ y^0-y^post6 == 0 /\ -y^post4+y^post6 == 0), cost: 1 Applied deletion Removed the following rules: 3 5 Eliminating location l2 by chaining: Applied chaining First rule: l0 -> l2 : x^0'=x^post2, y^0'=y^post2, (1-y^0 <= 0 /\ 1+y^post2-y^0 == 0 /\ x^0-x^post2 == 0), cost: 1 Second rule: l2 -> l0 : x^0'=x^post3, y^0'=y^post3, (y^0-y^post3 == 0 /\ x^0-x^post3 == 0), cost: 1 New rule: l0 -> l0 : x^0'=x^post3, y^0'=y^post3, (-x^post3+x^post2 == 0 /\ 1-y^0 <= 0 /\ y^post2-y^post3 == 0 /\ 1+y^post2-y^0 == 0 /\ x^0-x^post2 == 0), cost: 1 Applied deletion Removed the following rules: 1 2 Simplified Transitions Start location: l4 Program variables: x^0 y^0 8: l0 -> l1 : x^0'=-1+x^0, y^0'=1+y^0, y^0 <= 0, cost: 1 11: l0 -> l0 : y^0'=-1+y^0, 1-y^0 <= 0, cost: 1 9: l1 -> l0 : y^0'=x^0, 1-x^0 <= 0, cost: 1 10: l4 -> l1 : T, cost: 1 Propagated Equalities Original rule: l0 -> l1 : x^0'=x^post1, y^0'=y^post1, (1+x^post1-x^0 == 0 /\ y^0 <= 0 /\ -1+y^post1-y^0 == 0), cost: 1 New rule: l0 -> l1 : x^0'=-1+x^0, y^0'=1+y^0, (0 == 0 /\ y^0 <= 0), cost: 1 propagated equality x^post1 = -1+x^0 propagated equality y^post1 = 1+y^0 Simplified Guard Original rule: l0 -> l1 : x^0'=-1+x^0, y^0'=1+y^0, (0 == 0 /\ y^0 <= 0), cost: 1 New rule: l0 -> l1 : x^0'=-1+x^0, y^0'=1+y^0, y^0 <= 0, cost: 1 Propagated Equalities Original rule: l1 -> l0 : x^0'=x^post5, y^0'=y^post5, (1-x^0 <= 0 /\ y^post5-x^0 == 0 /\ x^0-x^post5 == 0), cost: 1 New rule: l1 -> l0 : x^0'=x^0, y^0'=x^0, (0 == 0 /\ 1-x^0 <= 0), cost: 1 propagated equality y^post5 = x^0 propagated equality x^post5 = x^0 Simplified Guard Original rule: l1 -> l0 : x^0'=x^0, y^0'=x^0, (0 == 0 /\ 1-x^0 <= 0), cost: 1 New rule: l1 -> l0 : x^0'=x^0, y^0'=x^0, 1-x^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l1 -> l0 : x^0'=x^0, y^0'=x^0, 1-x^0 <= 0, cost: 1 New rule: l1 -> l0 : y^0'=x^0, 1-x^0 <= 0, cost: 1 Propagated Equalities Original rule: l4 -> l1 : x^0'=x^post4, y^0'=y^post4, (x^0-x^post6 == 0 /\ -x^post4+x^post6 == 0 /\ y^0-y^post6 == 0 /\ -y^post4+y^post6 == 0), cost: 1 New rule: l4 -> l1 : x^0'=x^post6, y^0'=y^post6, (0 == 0 /\ x^0-x^post6 == 0 /\ y^0-y^post6 == 0), cost: 1 propagated equality x^post4 = x^post6 propagated equality y^post4 = y^post6 Propagated Equalities Original rule: l4 -> l1 : x^0'=x^post6, y^0'=y^post6, (0 == 0 /\ x^0-x^post6 == 0 /\ y^0-y^post6 == 0), cost: 1 New rule: l4 -> l1 : x^0'=x^0, y^0'=y^0, 0 == 0, cost: 1 propagated equality x^post6 = x^0 propagated equality y^post6 = y^0 Simplified Guard Original rule: l4 -> l1 : x^0'=x^0, y^0'=y^0, 0 == 0, cost: 1 New rule: l4 -> l1 : x^0'=x^0, y^0'=y^0, T, cost: 1 Removed Trivial Updates Original rule: l4 -> l1 : x^0'=x^0, y^0'=y^0, T, cost: 1 New rule: l4 -> l1 : T, cost: 1 Propagated Equalities Original rule: l0 -> l0 : x^0'=x^post3, y^0'=y^post3, (-x^post3+x^post2 == 0 /\ 1-y^0 <= 0 /\ y^post2-y^post3 == 0 /\ 1+y^post2-y^0 == 0 /\ x^0-x^post2 == 0), cost: 1 New rule: l0 -> l0 : x^0'=x^post2, y^0'=y^post2, (0 == 0 /\ 1-y^0 <= 0 /\ 1+y^post2-y^0 == 0 /\ x^0-x^post2 == 0), cost: 1 propagated equality x^post3 = x^post2 propagated equality y^post3 = y^post2 Propagated Equalities Original rule: l0 -> l0 : x^0'=x^post2, y^0'=y^post2, (0 == 0 /\ 1-y^0 <= 0 /\ 1+y^post2-y^0 == 0 /\ x^0-x^post2 == 0), cost: 1 New rule: l0 -> l0 : x^0'=x^0, y^0'=-1+y^0, (0 == 0 /\ 1-y^0 <= 0), cost: 1 propagated equality y^post2 = -1+y^0 propagated equality x^post2 = x^0 Simplified Guard Original rule: l0 -> l0 : x^0'=x^0, y^0'=-1+y^0, (0 == 0 /\ 1-y^0 <= 0), cost: 1 New rule: l0 -> l0 : x^0'=x^0, y^0'=-1+y^0, 1-y^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l0 -> l0 : x^0'=x^0, y^0'=-1+y^0, 1-y^0 <= 0, cost: 1 New rule: l0 -> l0 : y^0'=-1+y^0, 1-y^0 <= 0, cost: 1 Step with 10 Trace 10[T] Blocked [{}, {}] Step with 9 Trace 10[T], 9[(1-x^0 <= 0)] Blocked [{}, {}, {}] Step with 11 Trace 10[T], 9[(1-x^0 <= 0)], 11[(1-y^0 <= 0)] Blocked [{}, {}, {8[T]}, {}] Accelerate Start location: l4 Program variables: x^0 y^0 8: l0 -> l1 : x^0'=-1+x^0, y^0'=1+y^0, y^0 <= 0, cost: 1 11: l0 -> l0 : y^0'=-1+y^0, 1-y^0 <= 0, cost: 1 12: l0 -> l0 : y^0'=y^0-n, (y^0-n >= 0 /\ -1+n >= 0), cost: 1 9: l1 -> l0 : y^0'=x^0, 1-x^0 <= 0, cost: 1 10: l4 -> l1 : T, cost: 1 Loop Acceleration Original rule: l0 -> l0 : y^0'=-1+y^0, (1-y^0 <= 0), cost: 1 New rule: l0 -> l0 : y^0'=y^0-n, (y^0-n >= 0 /\ -1+n >= 0), cost: 1 -1+y^0 >= 0 [0]: montonic decrease yields y^0-n >= 0 -1+y^0 >= 0 [1]: eventual increase yields (1 <= 0 /\ -1+y^0 >= 0) Replacement map: {-1+y^0 >= 0 -> y^0-n >= 0} Trace 10[T], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)] Blocked [{}, {}, {8[T]}, {11[T], 12[T]}] Step with 8 Trace 10[T], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)], 8[(y^0 <= 0)] Blocked [{}, {}, {8[T]}, {11[T], 12[T]}, {}] Accelerate Start location: l4 Program variables: x^0 y^0 8: l0 -> l1 : x^0'=-1+x^0, y^0'=1+y^0, y^0 <= 0, cost: 1 11: l0 -> l0 : y^0'=-1+y^0, 1-y^0 <= 0, cost: 1 12: l0 -> l0 : y^0'=y^0-n, (y^0-n >= 0 /\ -1+n >= 0), cost: 1 9: l1 -> l0 : y^0'=x^0, 1-x^0 <= 0, cost: 1 13: l1 -> l1 : x^0'=x^0-n2, y^0'=1, (x^0-n2 >= 0 /\ -1+n2 >= 0), cost: 1 10: l4 -> l1 : T, cost: 1 Loop Acceleration Original rule: l1 -> l1 : x^0'=-1+x^0, y^0'=1, (1-x^0 <= 0 /\ -1+x^0 >= 0), cost: 1 New rule: l1 -> l1 : x^0'=x^0-n2, y^0'=1, (x^0-n2 >= 0 /\ -1+n2 >= 0), cost: 1 -1+x^0 >= 0 [0]: montonic decrease yields x^0-n2 >= 0 -1+x^0 >= 0 [1]: eventual increase yields (1 <= 0 /\ -1+x^0 >= 0) Replacement map: {-1+x^0 >= 0 -> x^0-n2 >= 0} Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)] Blocked [{}, {}, {13[T]}] Step with 9 Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)] Blocked [{}, {}, {13[T]}, {}] Step with 11 Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)], 11[(1-y^0 <= 0)] Blocked [{}, {}, {13[T]}, {8[T]}, {}] Covered Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)] Blocked [{}, {}, {13[T]}, {8[T], 11[T]}] Step with 12 Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)] Blocked [{}, {}, {13[T]}, {8[T], 11[T]}, {12[T]}] Step with 8 Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)], 8[(y^0 <= 0)] Blocked [{}, {}, {13[T]}, {8[T], 11[T]}, {12[T]}, {}] Covered Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)] Blocked [{}, {}, {13[T]}, {8[T], 11[T]}, {8[T], 12[T]}] Step with 11 Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)], 11[(1-y^0 <= 0)] Blocked [{}, {}, {13[T]}, {8[T], 11[T]}, {8[T], 12[T]}, {}] Covered Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)] Blocked [{}, {}, {13[T]}, {8[T], 11[T]}, {8[T], 11[T], 12[T]}] Backtrack Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)], 9[(1-x^0 <= 0)] Blocked [{}, {}, {13[T]}, {8[T], 11[T], 12[T]}] Backtrack Trace 10[T], 13[(x^0-n2 >= 0 /\ -1+n2 >= 0)] Blocked [{}, {}, {9[T], 13[T]}] Backtrack Trace 10[T] Blocked [{}, {13[T]}] Step with 9 Trace 10[T], 9[(1-x^0 <= 0)] Blocked [{}, {13[T]}, {}] Step with 11 Trace 10[T], 9[(1-x^0 <= 0)], 11[(1-y^0 <= 0)] Blocked [{}, {13[T]}, {}, {}] Covered Trace 10[T], 9[(1-x^0 <= 0)] Blocked [{}, {13[T]}, {11[T]}] Step with 12 Trace 10[T], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)] Blocked [{}, {13[T]}, {11[T]}, {12[T]}] Step with 8 Trace 10[T], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)], 8[(y^0 <= 0)] Blocked [{}, {13[T]}, {11[T]}, {12[T]}, {}] Covered Trace 10[T], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)] Blocked [{}, {13[T]}, {11[T]}, {8[T], 12[T]}] Step with 11 Trace 10[T], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)], 11[(1-y^0 <= 0)] Blocked [{}, {13[T]}, {11[T]}, {8[T], 12[T]}, {}] Covered Trace 10[T], 9[(1-x^0 <= 0)], 12[(y^0-n >= 0 /\ -1+n >= 0)] Blocked [{}, {13[T]}, {11[T]}, {8[T], 11[T], 12[T]}] Backtrack Trace 10[T], 9[(1-x^0 <= 0)] Blocked [{}, {13[T]}, {11[T], 12[T]}] Backtrack Trace 10[T] Blocked [{}, {9[T], 13[T]}] Backtrack Trace Blocked [{10[T]}] Accept unknown Build SHA: a05f16bf13df659c382799650051f91bf6828c7b