(0) Obligation:

The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(1, n^1).


The TRS R consists of the following rules:

digitsd(0)
d(x) → if(le(x, s(s(s(s(s(s(s(s(s(0)))))))))), x)
if(true, x) → cons(x, d(s(x)))
if(false, x) → nil
le(0, y) → true
le(s(x), 0) → false
le(s(x), s(y)) → le(x, y)

Rewrite Strategy: INNERMOST

(1) TrsToWeightedTrsProof (BOTH BOUNDS(ID, ID) transformation)

Transformed TRS to weighted TRS

(2) Obligation:

The Runtime Complexity (innermost) of the given CpxWeightedTrs could be proven to be BOUNDS(1, n^1).


The TRS R consists of the following rules:

digitsd(0) [1]
d(x) → if(le(x, s(s(s(s(s(s(s(s(s(0)))))))))), x) [1]
if(true, x) → cons(x, d(s(x))) [1]
if(false, x) → nil [1]
le(0, y) → true [1]
le(s(x), 0) → false [1]
le(s(x), s(y)) → le(x, y) [1]

Rewrite Strategy: INNERMOST

(3) TypeInferenceProof (BOTH BOUNDS(ID, ID) transformation)

Infered types.

(4) Obligation:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

digitsd(0) [1]
d(x) → if(le(x, s(s(s(s(s(s(s(s(s(0)))))))))), x) [1]
if(true, x) → cons(x, d(s(x))) [1]
if(false, x) → nil [1]
le(0, y) → true [1]
le(s(x), 0) → false [1]
le(s(x), s(y)) → le(x, y) [1]

The TRS has the following type information:
digits :: cons:nil
d :: 0:s → cons:nil
0 :: 0:s
if :: true:false → 0:s → cons:nil
le :: 0:s → 0:s → true:false
s :: 0:s → 0:s
true :: true:false
cons :: 0:s → cons:nil → cons:nil
false :: true:false
nil :: cons:nil

Rewrite Strategy: INNERMOST

(5) CompletionProof (UPPER BOUND(ID) transformation)

The TRS is a completely defined constructor system, as every type has a constant constructor and the following rules were added:
none

And the following fresh constants: none

(6) Obligation:

Runtime Complexity Weighted TRS where all functions are completely defined. The underlying TRS is:

Runtime Complexity Weighted TRS with Types.
The TRS R consists of the following rules:

digitsd(0) [1]
d(x) → if(le(x, s(s(s(s(s(s(s(s(s(0)))))))))), x) [1]
if(true, x) → cons(x, d(s(x))) [1]
if(false, x) → nil [1]
le(0, y) → true [1]
le(s(x), 0) → false [1]
le(s(x), s(y)) → le(x, y) [1]

The TRS has the following type information:
digits :: cons:nil
d :: 0:s → cons:nil
0 :: 0:s
if :: true:false → 0:s → cons:nil
le :: 0:s → 0:s → true:false
s :: 0:s → 0:s
true :: true:false
cons :: 0:s → cons:nil → cons:nil
false :: true:false
nil :: cons:nil

Rewrite Strategy: INNERMOST

(7) CpxTypedWeightedTrsToRntsProof (UPPER BOUND(ID) transformation)

Transformed the TRS into an over-approximating RNTS by (improved) Size Abstraction.
The constant constructors are abstracted as follows:

0 => 0
true => 1
false => 0
nil => 0

(8) Obligation:

Complexity RNTS consisting of the following rules:

d(z) -{ 1 }→ if(le(x, 1 + (1 + (1 + (1 + (1 + (1 + (1 + (1 + (1 + 0))))))))), x) :|: x >= 0, z = x
digits -{ 1 }→ d(0) :|:
if(z, z') -{ 1 }→ 0 :|: z' = x, x >= 0, z = 0
if(z, z') -{ 1 }→ 1 + x + d(1 + x) :|: z' = x, z = 1, x >= 0
le(z, z') -{ 1 }→ le(x, y) :|: z' = 1 + y, x >= 0, y >= 0, z = 1 + x
le(z, z') -{ 1 }→ 1 :|: y >= 0, z = 0, z' = y
le(z, z') -{ 1 }→ 0 :|: x >= 0, z = 1 + x, z' = 0

Only complete derivations are relevant for the runtime complexity.

(9) CompleteCoflocoProof (EQUIVALENT transformation)

Transformed the RNTS (where only complete derivations are relevant) into cost relations for CoFloCo:

eq(start(V, V2),0,[digits(Out)],[]).
eq(start(V, V2),0,[d(V, Out)],[V >= 0]).
eq(start(V, V2),0,[if(V, V2, Out)],[V >= 0,V2 >= 0]).
eq(start(V, V2),0,[le(V, V2, Out)],[V >= 0,V2 >= 0]).
eq(digits(Out),1,[d(0, Ret)],[Out = Ret]).
eq(d(V, Out),1,[le(V1, 1 + (1 + (1 + (1 + (1 + (1 + (1 + (1 + (1 + 0)))))))), Ret0),if(Ret0, V1, Ret1)],[Out = Ret1,V1 >= 0,V = V1]).
eq(if(V, V2, Out),1,[d(1 + V3, Ret11)],[Out = 1 + Ret11 + V3,V2 = V3,V = 1,V3 >= 0]).
eq(if(V, V2, Out),1,[],[Out = 0,V2 = V4,V4 >= 0,V = 0]).
eq(le(V, V2, Out),1,[],[Out = 1,V5 >= 0,V = 0,V2 = V5]).
eq(le(V, V2, Out),1,[],[Out = 0,V6 >= 0,V = 1 + V6,V2 = 0]).
eq(le(V, V2, Out),1,[le(V7, V8, Ret2)],[Out = Ret2,V2 = 1 + V8,V7 >= 0,V8 >= 0,V = 1 + V7]).
input_output_vars(digits(Out),[],[Out]).
input_output_vars(d(V,Out),[V],[Out]).
input_output_vars(if(V,V2,Out),[V,V2],[Out]).
input_output_vars(le(V,V2,Out),[V,V2],[Out]).

CoFloCo proof output:
Preprocessing Cost Relations
=====================================

#### Computed strongly connected components
0. recursive : [le/3]
1. recursive : [d/2,if/3]
2. non_recursive : [digits/1]
3. non_recursive : [start/2]

#### Obtained direct recursion through partial evaluation
0. SCC is partially evaluated into le/3
1. SCC is partially evaluated into d/2
2. SCC is completely evaluated into other SCCs
3. SCC is partially evaluated into start/2

Control-Flow Refinement of Cost Relations
=====================================

### Specialization of cost equations le/3
* CE 11 is refined into CE [12]
* CE 10 is refined into CE [13]
* CE 9 is refined into CE [14]


### Cost equations --> "Loop" of le/3
* CEs [13] --> Loop 7
* CEs [14] --> Loop 8
* CEs [12] --> Loop 9

### Ranking functions of CR le(V,V2,Out)
* RF of phase [9]: [V,V2]

#### Partial ranking functions of CR le(V,V2,Out)
* Partial RF of phase [9]:
- RF of loop [9:1]:
V
V2


### Specialization of cost equations d/2
* CE 8 is refined into CE [15,16]
* CE 7 is refined into CE [17]


### Cost equations --> "Loop" of d/2
* CEs [17] --> Loop 10
* CEs [16] --> Loop 11
* CEs [15] --> Loop 12

### Ranking functions of CR d(V,Out)
* RF of phase [11]: [-V+10]

#### Partial ranking functions of CR d(V,Out)
* Partial RF of phase [11]:
- RF of loop [11:1]:
-V+10


### Specialization of cost equations start/2
* CE 2 is refined into CE [18]
* CE 3 is refined into CE [19,20]
* CE 4 is refined into CE [21]
* CE 5 is refined into CE [22,23,24]
* CE 6 is refined into CE [25,26,27,28]


### Cost equations --> "Loop" of start/2
* CEs [18,19,20,21,22,23,24,25,26,27,28] --> Loop 13

### Ranking functions of CR start(V,V2)

#### Partial ranking functions of CR start(V,V2)


Computing Bounds
=====================================

#### Cost of chains of le(V,V2,Out):
* Chain [[9],8]: 1*it(9)+1
Such that:it(9) =< V

with precondition: [Out=1,V>=1,V2>=V]

* Chain [[9],7]: 1*it(9)+1
Such that:it(9) =< V2

with precondition: [Out=0,V2>=1,V>=V2+1]

* Chain [8]: 1
with precondition: [V=0,Out=1,V2>=0]

* Chain [7]: 1
with precondition: [V2=0,Out=0,V>=1]


#### Cost of chains of d(V,Out):
* Chain [[11],10]: 3*it(11)+1*s(1)+1*s(4)+3
Such that:s(1) =< 9
s(4) =< -9*V+90
it(11) =< -V+10

with precondition: [9>=V,V>=1]

* Chain [12,[11],10]: 4*it(11)+1*s(4)+6
Such that:s(4) =< 81
aux(1) =< 9
it(11) =< aux(1)

with precondition: [V=0]

* Chain [10]: 1*s(1)+3
Such that:s(1) =< 9

with precondition: [Out=0,V>=10]


#### Cost of chains of start(V,V2):
* Chain [13]: 12*s(5)+1*s(7)+3*s(8)+2*s(9)+1*s(17)+3*s(18)+1*s(19)+1*s(20)+7
Such that:s(17) =< -9*V+90
s(18) =< -V+10
s(20) =< V
s(7) =< -9*V2+81
s(8) =< -V2+9
s(19) =< V2
aux(2) =< 9
aux(3) =< 81
s(5) =< aux(2)
s(9) =< aux(3)

with precondition: []


Closed-form bounds of start(V,V2):
-------------------------------------
* Chain [13] with precondition: []
- Upper bound: nat(V)+277+nat(V2)+nat(-V+10)*3+nat(-V2+9)*3+nat(-9*V+90)+nat(-9*V2+81)
- Complexity: n

### Maximum cost of start(V,V2): nat(V)+277+nat(V2)+nat(-V+10)*3+nat(-V2+9)*3+nat(-9*V+90)+nat(-9*V2+81)
Asymptotic class: n
* Total analysis performed in 141 ms.

(10) BOUNDS(1, n^1)