|
| 1 | +#Axt_mul_Bx |
| 2 | + |
| 3 | +export Axt_mul_Bx |
| 4 | + |
| 5 | +""" |
| 6 | +`Axt_mul_Bx(A::AbstractOperator,B::AbstractOperator)` |
| 7 | +
|
| 8 | +Create an operator `P` such that: |
| 9 | +
|
| 10 | +`P*x == (Ax)'*(Bx)` |
| 11 | +
|
| 12 | +# Example |
| 13 | +
|
| 14 | +```julia |
| 15 | +julia> A,B = randn(4,4),randn(4,4); |
| 16 | +
|
| 17 | +julia> P = Axt_mul_Bx(MatrixOp(A),MatrixOp(B)) |
| 18 | +▒*▒ ℝ^4 -> ℝ^1 |
| 19 | +
|
| 20 | +julia> x = randn(4); |
| 21 | +
|
| 22 | +julia> P*x == [(A*x)'*(B*x)] |
| 23 | +true |
| 24 | +
|
| 25 | +``` |
| 26 | +""" |
| 27 | +struct Axt_mul_Bx{N, |
| 28 | + L1 <: AbstractOperator, |
| 29 | + L2 <: AbstractOperator, |
| 30 | + C <: AbstractArray, |
| 31 | + D <: AbstractArray, |
| 32 | + } <: NonLinearOperator |
| 33 | + A::L1 |
| 34 | + B::L2 |
| 35 | + bufA::C |
| 36 | + bufB::C |
| 37 | + bufC::C |
| 38 | + bufD::D |
| 39 | + function Axt_mul_Bx(A::L1, B::L2, bufA::C, bufB::C, bufC::C, bufD::D) where {L1,L2,C,D} |
| 40 | + if ndims(A,1) == 1 |
| 41 | + if size(A) != size(B) |
| 42 | + throw(DimensionMismatch("Cannot compose operators")) |
| 43 | + end |
| 44 | + elseif ndims(A,1) == 2 && ndims(B,1) == 2 && size(A,2) == size(B,2) |
| 45 | + if size(A,1)[1] != size(B,1)[1] |
| 46 | + throw(DimensionMismatch("Cannot compose operators")) |
| 47 | + end |
| 48 | + else |
| 49 | + throw(DimensionMismatch("Cannot compose operators")) |
| 50 | + end |
| 51 | + N = ndims(A,1) |
| 52 | + new{N,L1,L2,C,D}(A,B,bufA,bufB,bufC,bufD) |
| 53 | + end |
| 54 | +end |
| 55 | + |
| 56 | +struct Axt_mul_BxJac{N, |
| 57 | + L1 <: AbstractOperator, |
| 58 | + L2 <: AbstractOperator, |
| 59 | + C <: AbstractArray, |
| 60 | + D <: AbstractArray, |
| 61 | + } <: LinearOperator |
| 62 | + A::L1 |
| 63 | + B::L2 |
| 64 | + bufA::C |
| 65 | + bufB::C |
| 66 | + bufC::C |
| 67 | + bufD::D |
| 68 | +end |
| 69 | + |
| 70 | +# Constructors |
| 71 | +function Axt_mul_Bx(A::AbstractOperator,B::AbstractOperator) |
| 72 | + s,t = size(A,1), codomainType(A) |
| 73 | + bufA = eltype(s) <: Int ? zeros(t,s) : ArrayPartition(zeros.(t,s)...) |
| 74 | + bufC = eltype(s) <: Int ? zeros(t,s) : ArrayPartition(zeros.(t,s)...) |
| 75 | + s,t = size(B,1), codomainType(B) |
| 76 | + bufB = eltype(s) <: Int ? zeros(t,s) : ArrayPartition(zeros.(t,s)...) |
| 77 | + s,t = size(A,2), domainType(A) |
| 78 | + bufD = eltype(s) <: Int ? zeros(t,s) : ArrayPartition(zeros.(t,s)...) |
| 79 | + Axt_mul_Bx(A,B,bufA,bufB,bufC,bufD) |
| 80 | +end |
| 81 | + |
| 82 | +# Jacobian |
| 83 | +function Jacobian(P::Axt_mul_Bx{N,L1,L2,C,D}, x::AbstractArray) where {N,L1,L2,C,D} |
| 84 | + JA, JB = Jacobian(P.A, x), Jacobian(P.B, x) |
| 85 | + Axt_mul_BxJac{N,typeof(JA),typeof(JB),C,D}(JA,JB,P.bufA,P.bufB,P.bufC,P.bufD) |
| 86 | +end |
| 87 | + |
| 88 | +# Mappings |
| 89 | +# N == 1 input is a vector |
| 90 | +function mul!(y, P::Axt_mul_Bx{1,L1,L2,C,D}, b) where {L1,L2,C,D} |
| 91 | + mul!(P.bufA,P.A,b) |
| 92 | + mul!(P.bufB,P.B,b) |
| 93 | + y[1] = dot(P.bufA,P.bufB) |
| 94 | +end |
| 95 | + |
| 96 | +function mul!(y, J::AdjointOperator{Axt_mul_BxJac{1,L1,L2,C,D}}, b) where {L1,L2,C,D} |
| 97 | + #y .= conj(J.A.A'*J.A.bufB+J.A.B'*J.A.bufA).*b[1] |
| 98 | + mul!(y, J.A.A', J.A.bufB) |
| 99 | + mul!(J.A.bufD, J.A.B', J.A.bufA) |
| 100 | + y .= conj.( y .+ J.A.bufD ) .* b[1] |
| 101 | + return y |
| 102 | +end |
| 103 | + |
| 104 | +# N == 2 input is a matrix |
| 105 | +function mul!(y, P::Axt_mul_Bx{2,L1,L2,C,D}, b) where {L1,L2,C,D} |
| 106 | + mul!(P.bufA,P.A,b) |
| 107 | + mul!(P.bufB,P.B,b) |
| 108 | + mul!(y,P.bufA',P.bufB) |
| 109 | + return y |
| 110 | +end |
| 111 | + |
| 112 | +function mul!(y, J::AdjointOperator{Axt_mul_BxJac{2,L1,L2,C,D}}, b) where {L1,L2,C,D} |
| 113 | + # y .= J.A.A'*((J.A.bufB)*b') + J.A.B'*((J.A.bufA)*b) |
| 114 | + mul!(J.A.bufC, J.A.bufB, b') |
| 115 | + mul!(y, J.A.A', J.A.bufC) |
| 116 | + mul!(J.A.bufB, J.A.bufA, b) |
| 117 | + mul!(J.A.bufD, J.A.B', J.A.bufB) |
| 118 | + y .+= J.A.bufD |
| 119 | + return y |
| 120 | +end |
| 121 | + |
| 122 | +size(P::Union{Axt_mul_Bx{1},Axt_mul_BxJac{1}}) = ((1,),size(P.A,2)) |
| 123 | +size(P::Union{Axt_mul_Bx{2},Axt_mul_BxJac{2}}) = ((size(P.A,1)[2],size(P.B,1)[2]),size(P.A,2)) |
| 124 | + |
| 125 | +fun_name(L::Union{Axt_mul_Bx,Axt_mul_BxJac}) = fun_name(L.A)*"*"*fun_name(L.B) |
| 126 | + |
| 127 | +domainType(L::Union{Axt_mul_Bx,Axt_mul_BxJac}) = domainType(L.A) |
| 128 | +codomainType(L::Union{Axt_mul_Bx,Axt_mul_BxJac}) = codomainType(L.A) |
| 129 | + |
| 130 | +# utils |
| 131 | +function permute(P::Axt_mul_Bx{N,L1,L2,C,D}, |
| 132 | + p::AbstractVector{Int}) where {N,L1,L2,C,D <:ArrayPartition} |
| 133 | + Axt_mul_Bx(permute(P.A,p),permute(P.B,p),P.bufA,P.bufB,P.bufC,ArrayPartition(P.bufD.x[p]) ) |
| 134 | +end |
| 135 | + |
| 136 | +remove_displacement(P::Axt_mul_Bx) = |
| 137 | +Axt_mul_Bx(remove_displacement(P.A), remove_displacement(P.B), P.bufA, P.bufB, P.bufC, P.bufD) |
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