1	# IProblem box — variable count + per-var [lo, hi].
2	# Named problems live in problems.bend.
3	
4	import Base
5	
6	type Interval is Data:
7	  MkInterval{
8	    low: F32
9	    high: F32
10	  }
11	
12	type Box is Data:
13	  MkBox{
14	    m: Nat
15	    ivs: List<&2, Interval>
16	  }
17	
18	def interval(+low: F32, +high: F32) -> Interval:
19	  MkInterval{low, high}
20	
21	def lo(b: Interval) -> F32:
22	  match b:
23	    case MkInterval{low, high}:
24	      low
25	
26	def hi(b: Interval) -> F32:
27	  match b:
28	    case MkInterval{low, high}:
29	      high
30	
31	def box(+m: Nat, ivs: List<&2, Interval>) -> Box:
32	  MkBox{m, ivs}
33	
34	def n_obj(b: Box) -> Nat:
35	  match b:
36	    case MkBox{m, ivs}:
37	      m
38	
39	def intervals_of(b: Box) -> List<&2, Interval>:
40	  match b:
41	    case MkBox{m, ivs}:
42	      ivs
43	
44	def n_var(b: Box) -> Nat:
45	  List.length(&2, Interval, intervals_of(b))
46	
47	def at.go(m: Maybe<&2, Interval>) -> Interval:
48	  match m:
49	    case None{}:
50	      MkInterval{0.0, 1.0}
51	    case Some{iv}:
52	      iv
53	
54	def at(b: Box, i: Nat) -> Interval:
55	  at.go(List.get(&2, Interval, intervals_of(b), i))
56	
57	# nv copies of [0, 1]. Smoke / operator tests; unit ZDT / DTLZ boxes.
58	def unit_n(nv: Nat, nm: Nat) -> Box:
59	  MkBox{nm, List.replicate(Interval, nv, MkInterval{0.0, 1.0})}
60	
61	# nv copies of [low, high]. Sphere / Ackley / Rosenbrock and any uniform range.
62	def span_n(nv: Nat, nm: Nat, +low: F32, +high: F32) -> Box:
63	  MkBox{nm, List.replicate(Interval, nv, MkInterval{low, high})}