comparison TensorMappings.jl @ 155:9fdbae11dd77 boundary_conditions

Add sketch of how Implicitly definied tensor mappings might work
author Jonatan Werpers <jonatan@werpers.com>
date Tue, 23 Apr 2019 09:54:42 +0200
parents
children ef3e6c70b6f9
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154:3193bac1c086 155:9fdbae11dd77
1 module TensorMappings
2 # Needs a better name ImplicitTensorMappings? Get rid of "Tensor" in the name_
3
4 abstract type TensorMapping{T,R,D} end
5 abstract type TensorOperator{T,D} <: TensorMapping{T,D,D} end # Does this help?
6
7 range_dim(::TensorMapping{T,R,D}) where {T,R,D} = R
8 domain_dim(::TensorMapping{T,R,D}) where {T,R,D} = D
9
10 range_size(::TensorOperator{T,D}, domain_size::NTuple{D,Integer}) where {T,D} = domain_size
11 # More prciese domain_size type?
12
13 # Should be implemented by a TensorMapping
14 # ========================================
15 # apply(t::TensorMapping{T,R,D}, v::AbstractArray{T,D}, I::Vararg) where {R,D,T} =
16 # apply_transpose(t::TensorMapping{T,R,D}, v::AbstractArray{T,D}, I::Vararg) where {R,D,T} =
17 # Does it make sense that apply should work for any size of v? And the application adapts?
18 # Think about boundschecking!
19
20 # range_size(::TensorMapping{T,R,D}, domain_size::NTuple{D,Integer}) where {T,R,D} =
21 # More prciese domain_size type?
22 # range_size_of_transpose()???
23
24
25
26 # Allow using the ' operator:
27 struct TensorMappingTranspose{T,R,D} <: TensorMapping{T,D,R}
28 tm::TensorMapping{T,R,D}
29 end
30
31 Base.adjoint(t::TensorMapping) = TensorMappingTranspose(t) # Maybe this should be implemented on a type by type basis or through a trait to provide earlier errors.
32 Base.adjoint(t::TensorMappingTranspose) = t.tm
33
34 apply(tm::TensorMappingTranspose{T,R,D}, v::AbstractArray{T,R}, I::Vararg) where {T,R,D} = apply_transpose(tm.tm, v, I...)
35 apply_transpose(tm::TensorMappingTranspose{T,R,D}, v::AbstractArray{T,D}, I::Vararg) where {T,R,D} = apply(tm.tm, v, I...)
36
37 # range_size(::TensorMappingTranspose{T,R,D}, domain_size::NTuple{}) = range_size_of_transpose???
38
39 struct TensorApplication{T,R,D} <: AbstractArray{T,R}
40 t::TensorMapping{R,D}
41 o::AbstractArray{T,D}
42 end
43
44 Base.size(ta::TensorApplication) = range_size(ta.t,size(ta.o))
45 ## What else is needed so that we have a proper AbstractArray?
46
47 Base.getindex(tm::TensorApplication, I::Vararg) = apply(tm.t, tm.o, I...)
48
49 →(t::TensorMapping{R,D}, o::AbstractArray{T,D}) where {T,R,D} = TensorApplication(t,o)
50 # Should we overload some other infix binary operator?
51 # * has the wrong parsing properties... a*b*c is parsed to (a*b)*c (through a*b*c = *(a,b,c))
52 # while a→b→c is parsed as a→(b→c)
53 # The associativity of the operators might be fixed somehow... (rfold/lfold?)
54 # ∘ also is an option but that has the same problem as * (but is not n-ary) (or is this best used for composition of Mappings?)
55
56
57 struct TensorMappingComposition{T,R,K,D} <: TensorMapping{T,R,D}
58 t1::TensorMapping{T,R,K}
59 t2::TensorMapping{T,K,D}
60 end
61
62 import Base.∘
63 ∘(s::TensorMapping{T,R,K}, t::TensorMapping{T,K,D}) where {T,R,K,D} = TensorMappingComposition(s,t)
64
65 function apply(c::TensorMappingComposition{T,R,K,D}, v::AbstractArray{T,D}, I::Vararg) where {T,R,K,D}
66 apply(c.t1, TensorApplication(c.t2,v), I...)
67 end
68
69 function apply_transpose(c::TensorMappingComposition{T,R,K,D}, v::AbstractArray{T,D}, I::Vararg) where {T,R,K,D}
70 apply_transpose(c.t2, TensorApplication(c.t1',v), I...)
71 end
72
73 # Have i gone too crazy with the type parameters? Maybe they aren't all needed?
74
75
76 export apply
77 export apply_transpose
78 export range_dim
79 export domain_dim
80 export range_size
81 export →
82
83
84 end #module