WORST_CASE(Omega(1),?) ### Pre-processing the ITS problem ### Initial linear ITS problem Start location: __init 0: f1 -> f2 : arg1'=arg1P_1, arg2'=arg2P_1, arg3'=arg3P_1, arg4'=arg4P_1, [ arg1==arg1P_1 && arg2==arg2P_1 && arg4==arg4P_1 ], cost: 1 1: f2 -> f3 : arg1'=arg1P_2, arg2'=arg2P_2, arg3'=arg3P_2, arg4'=arg4P_2, [ arg1==arg1P_2 && arg2==arg2P_2 && arg3==arg3P_2 ], cost: 1 2: f3 -> f4 : arg1'=arg1P_3, arg2'=arg2P_3, arg3'=arg3P_3, arg4'=arg4P_3, [ arg2==arg2P_3 && arg3==arg3P_3 && arg4==arg4P_3 ], cost: 1 3: f4 -> f5 : arg1'=arg1P_4, arg2'=arg2P_4, arg3'=arg3P_4, arg4'=arg4P_4, [ arg1==arg1P_4 && arg3==arg3P_4 && arg4==arg4P_4 ], cost: 1 10: f5 -> f6 : arg1'=arg1P_11, arg2'=arg2P_11, arg3'=arg3P_11, arg4'=arg4P_11, [ arg3==1+arg4 && arg1<0 && arg1==arg1P_11 && arg2==arg2P_11 && arg3==arg3P_11 && arg4==arg4P_11 ], cost: 1 11: f5 -> f7 : arg1'=arg1P_12, arg2'=arg2P_12, arg3'=arg3P_12, arg4'=arg4P_12, [ arg1>=0 && arg1==arg1P_12 && arg2==arg2P_12 && arg3==arg3P_12 && arg4==arg4P_12 ], cost: 1 12: f5 -> f7 : arg1'=arg1P_13, arg2'=arg2P_13, arg3'=arg3P_13, arg4'=arg4P_13, [ arg3<1+arg4 && arg1==arg1P_13 && arg2==arg2P_13 && arg3==arg3P_13 && arg4==arg4P_13 ], cost: 1 13: f5 -> f7 : arg1'=arg1P_14, arg2'=arg2P_14, arg3'=arg3P_14, arg4'=arg4P_14, [ arg3>1+arg4 && arg1==arg1P_14 && arg2==arg2P_14 && arg3==arg3P_14 && arg4==arg4P_14 ], cost: 1 4: f9 -> f10 : arg1'=arg1P_5, arg2'=arg2P_5, arg3'=arg3P_5, arg4'=arg4P_5, [ arg1P_5==-1+arg3-arg4+arg1 && arg2==arg2P_5 && arg3==arg3P_5 && arg4==arg4P_5 ], cost: 1 5: f10 -> f11 : arg1'=arg1P_6, arg2'=arg2P_6, arg3'=arg3P_6, arg4'=arg4P_6, [ arg2P_6==-1+arg2-arg3+arg4 && arg1==arg1P_6 && arg3==arg3P_6 && arg4==arg4P_6 ], cost: 1 8: f11 -> f6 : arg1'=arg1P_9, arg2'=arg2P_9, arg3'=arg3P_9, arg4'=arg4P_9, [ arg1==arg1P_9 && arg2==arg2P_9 && arg3==arg3P_9 && arg4==arg4P_9 ], cost: 1 6: f6 -> f9 : arg1'=arg1P_7, arg2'=arg2P_7, arg3'=arg3P_7, arg4'=arg4P_7, [ arg1>=0 && arg1==arg1P_7 && arg2==arg2P_7 && arg3==arg3P_7 && arg4==arg4P_7 ], cost: 1 7: f6 -> f9 : arg1'=arg1P_8, arg2'=arg2P_8, arg3'=arg3P_8, arg4'=arg4P_8, [ arg2>=0 && arg1==arg1P_8 && arg2==arg2P_8 && arg3==arg3P_8 && arg4==arg4P_8 ], cost: 1 9: f6 -> f12 : arg1'=arg1P_10, arg2'=arg2P_10, arg3'=arg3P_10, arg4'=arg4P_10, [ arg1<0 && arg2<0 && arg1==arg1P_10 && arg2==arg2P_10 && arg3==arg3P_10 && arg4==arg4P_10 ], cost: 1 14: f12 -> f8 : arg1'=arg1P_15, arg2'=arg2P_15, arg3'=arg3P_15, arg4'=arg4P_15, [ arg1==arg1P_15 && arg2==arg2P_15 && arg3==arg3P_15 && arg4==arg4P_15 ], cost: 1 15: f7 -> f8 : arg1'=arg1P_16, arg2'=arg2P_16, arg3'=arg3P_16, arg4'=arg4P_16, [ arg1==arg1P_16 && arg2==arg2P_16 && arg3==arg3P_16 && arg4==arg4P_16 ], cost: 1 16: __init -> f1 : arg1'=arg1P_17, arg2'=arg2P_17, arg3'=arg3P_17, arg4'=arg4P_17, [], cost: 1 Checking for constant complexity: The following rule is satisfiable with cost >= 1, yielding constant complexity: 16: __init -> f1 : arg1'=arg1P_17, arg2'=arg2P_17, arg3'=arg3P_17, arg4'=arg4P_17, [], cost: 1 Removed unreachable and leaf rules: Start location: __init 0: f1 -> f2 : arg1'=arg1P_1, arg2'=arg2P_1, arg3'=arg3P_1, arg4'=arg4P_1, [ arg1==arg1P_1 && arg2==arg2P_1 && arg4==arg4P_1 ], cost: 1 1: f2 -> f3 : arg1'=arg1P_2, arg2'=arg2P_2, arg3'=arg3P_2, arg4'=arg4P_2, [ arg1==arg1P_2 && arg2==arg2P_2 && arg3==arg3P_2 ], cost: 1 2: f3 -> f4 : arg1'=arg1P_3, arg2'=arg2P_3, arg3'=arg3P_3, arg4'=arg4P_3, [ arg2==arg2P_3 && arg3==arg3P_3 && arg4==arg4P_3 ], cost: 1 3: f4 -> f5 : arg1'=arg1P_4, arg2'=arg2P_4, arg3'=arg3P_4, arg4'=arg4P_4, [ arg1==arg1P_4 && arg3==arg3P_4 && arg4==arg4P_4 ], cost: 1 10: f5 -> f6 : arg1'=arg1P_11, arg2'=arg2P_11, arg3'=arg3P_11, arg4'=arg4P_11, [ arg3==1+arg4 && arg1<0 && arg1==arg1P_11 && arg2==arg2P_11 && arg3==arg3P_11 && arg4==arg4P_11 ], cost: 1 4: f9 -> f10 : arg1'=arg1P_5, arg2'=arg2P_5, arg3'=arg3P_5, arg4'=arg4P_5, [ arg1P_5==-1+arg3-arg4+arg1 && arg2==arg2P_5 && arg3==arg3P_5 && arg4==arg4P_5 ], cost: 1 5: f10 -> f11 : arg1'=arg1P_6, arg2'=arg2P_6, arg3'=arg3P_6, arg4'=arg4P_6, [ arg2P_6==-1+arg2-arg3+arg4 && arg1==arg1P_6 && arg3==arg3P_6 && arg4==arg4P_6 ], cost: 1 8: f11 -> f6 : arg1'=arg1P_9, arg2'=arg2P_9, arg3'=arg3P_9, arg4'=arg4P_9, [ arg1==arg1P_9 && arg2==arg2P_9 && arg3==arg3P_9 && arg4==arg4P_9 ], cost: 1 6: f6 -> f9 : arg1'=arg1P_7, arg2'=arg2P_7, arg3'=arg3P_7, arg4'=arg4P_7, [ arg1>=0 && arg1==arg1P_7 && arg2==arg2P_7 && arg3==arg3P_7 && arg4==arg4P_7 ], cost: 1 7: f6 -> f9 : arg1'=arg1P_8, arg2'=arg2P_8, arg3'=arg3P_8, arg4'=arg4P_8, [ arg2>=0 && arg1==arg1P_8 && arg2==arg2P_8 && arg3==arg3P_8 && arg4==arg4P_8 ], cost: 1 16: __init -> f1 : arg1'=arg1P_17, arg2'=arg2P_17, arg3'=arg3P_17, arg4'=arg4P_17, [], cost: 1 Simplified all rules, resulting in: Start location: __init 0: f1 -> f2 : arg3'=arg3P_1, [], cost: 1 1: f2 -> f3 : arg4'=arg4P_2, [], cost: 1 2: f3 -> f4 : arg1'=arg1P_3, [], cost: 1 3: f4 -> f5 : arg2'=arg2P_4, [], cost: 1 10: f5 -> f6 : [ arg3==1+arg4 && arg1<0 ], cost: 1 4: f9 -> f10 : arg1'=-1+arg3-arg4+arg1, [], cost: 1 5: f10 -> f11 : arg2'=-1+arg2-arg3+arg4, [], cost: 1 8: f11 -> f6 : [], cost: 1 6: f6 -> f9 : [ arg1>=0 ], cost: 1 7: f6 -> f9 : [ arg2>=0 ], cost: 1 16: __init -> f1 : arg1'=arg1P_17, arg2'=arg2P_17, arg3'=arg3P_17, arg4'=arg4P_17, [], cost: 1 ### Simplification by acceleration and chaining ### Eliminated locations (on linear paths): Start location: __init 23: f9 -> f6 : arg1'=-1+arg3-arg4+arg1, arg2'=-1+arg2-arg3+arg4, [], cost: 3 6: f6 -> f9 : [ arg1>=0 ], cost: 1 7: f6 -> f9 : [ arg2>=0 ], cost: 1 21: __init -> f6 : arg1'=arg1P_3, arg2'=arg2P_4, arg3'=arg3P_1, arg4'=arg4P_2, [ arg3P_1==1+arg4P_2 && arg1P_3<0 ], cost: 6 Eliminated locations (on tree-shaped paths): Start location: __init 24: f6 -> f6 : arg1'=-1+arg3-arg4+arg1, arg2'=-1+arg2-arg3+arg4, [ arg1>=0 ], cost: 4 25: f6 -> f6 : arg1'=-1+arg3-arg4+arg1, arg2'=-1+arg2-arg3+arg4, [ arg2>=0 ], cost: 4 21: __init -> f6 : arg1'=arg1P_3, arg2'=arg2P_4, arg3'=arg3P_1, arg4'=arg4P_2, [ arg3P_1==1+arg4P_2 && arg1P_3<0 ], cost: 6 Accelerating simple loops of location 8. Accelerating the following rules: 24: f6 -> f6 : arg1'=-1+arg3-arg4+arg1, arg2'=-1+arg2-arg3+arg4, [ arg1>=0 ], cost: 4 25: f6 -> f6 : arg1'=-1+arg3-arg4+arg1, arg2'=-1+arg2-arg3+arg4, [ arg2>=0 ], cost: 4 Accelerated rule 24 with non-termination, yielding the new rule 26. [test] deduced invariant 1-arg3+arg4<=0 Accelerated rule 25 with non-termination, yielding the new rule 27. Accelerated rule 25 with backward acceleration, yielding the new rule 28. [accelerate] Nesting with 1 inner and 2 outer candidates Accelerated all simple loops using metering functions (where possible): Start location: __init 24: f6 -> f6 : arg1'=-1+arg3-arg4+arg1, arg2'=-1+arg2-arg3+arg4, [ arg1>=0 ], cost: 4 25: f6 -> f6 : arg1'=-1+arg3-arg4+arg1, arg2'=-1+arg2-arg3+arg4, [ arg2>=0 ], cost: 4 26: f6 -> [13] : [ arg3==1 && arg4==0 && arg1==0 ], cost: NONTERM 27: f6 -> [13] : [ arg2==0 && arg3==-1 && arg4==0 ], cost: NONTERM 28: f6 -> f6 : arg1'=-k*arg4-k+k*arg3+arg1, arg2'=k*arg4+arg2-k-k*arg3, [ 1-arg3+arg4<=0 && k>=0 && 1+(-1+k)*arg4+arg2-k-arg3*(-1+k)>=0 ], cost: 4*k 21: __init -> f6 : arg1'=arg1P_3, arg2'=arg2P_4, arg3'=arg3P_1, arg4'=arg4P_2, [ arg3P_1==1+arg4P_2 && arg1P_3<0 ], cost: 6 Chained accelerated rules (with incoming rules): Start location: __init 21: __init -> f6 : arg1'=arg1P_3, arg2'=arg2P_4, arg3'=arg3P_1, arg4'=arg4P_2, [ arg3P_1==1+arg4P_2 && arg1P_3<0 ], cost: 6 29: __init -> f6 : arg1'=arg1P_3, arg2'=-2+arg2P_4, arg3'=1+arg4P_2, arg4'=arg4P_2, [ arg1P_3<0 && arg2P_4>=0 ], cost: 10 30: __init -> f6 : arg1'=arg1P_3-k-k*arg4P_2+k*(1+arg4P_2), arg2'=-k+k*arg4P_2+arg2P_4-k*(1+arg4P_2), arg3'=1+arg4P_2, arg4'=arg4P_2, [ arg1P_3<0 && k>=0 && 1+arg4P_2*(-1+k)-(1+arg4P_2)*(-1+k)-k+arg2P_4>=0 ], cost: 6+4*k Removed unreachable locations (and leaf rules with constant cost): Start location: __init 30: __init -> f6 : arg1'=arg1P_3-k-k*arg4P_2+k*(1+arg4P_2), arg2'=-k+k*arg4P_2+arg2P_4-k*(1+arg4P_2), arg3'=1+arg4P_2, arg4'=arg4P_2, [ arg1P_3<0 && k>=0 && 1+arg4P_2*(-1+k)-(1+arg4P_2)*(-1+k)-k+arg2P_4>=0 ], cost: 6+4*k ### Computing asymptotic complexity ### Fully simplified ITS problem Start location: __init 30: __init -> f6 : arg1'=arg1P_3-k-k*arg4P_2+k*(1+arg4P_2), arg2'=-k+k*arg4P_2+arg2P_4-k*(1+arg4P_2), arg3'=1+arg4P_2, arg4'=arg4P_2, [ arg1P_3<0 && k>=0 && 1+arg4P_2*(-1+k)-(1+arg4P_2)*(-1+k)-k+arg2P_4>=0 ], cost: 6+4*k Computing asymptotic complexity for rule 30 Resulting cost 0 has complexity: Unknown Obtained the following overall complexity (w.r.t. the length of the input n): Complexity: Constant Cpx degree: 0 Solved cost: 1 Rule cost: 1 Rule guard: [] WORST_CASE(Omega(1),?)