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|  | 1 | +module ForwardDiffStaticArraysExt | 
|  | 2 | + | 
|  | 3 | +using ForwardDiff, StaticArrays | 
|  | 4 | +using ForwardDiff.LinearAlgebra | 
|  | 5 | +using ForwardDiff.DiffResults | 
|  | 6 | +using ForwardDiff: Dual, partials, GradientConfig, JacobianConfig, HessianConfig, Tag, Chunk, | 
|  | 7 | +                   gradient, hessian, jacobian, gradient!, hessian!, jacobian!, | 
|  | 8 | +                   extract_gradient!, extract_jacobian!, extract_value!, | 
|  | 9 | +                   vector_mode_gradient, vector_mode_gradient!, | 
|  | 10 | +                   vector_mode_jacobian, vector_mode_jacobian!, valtype, value, _lyap_div! | 
|  | 11 | +using DiffResults: DiffResult, ImmutableDiffResult, MutableDiffResult | 
|  | 12 | + | 
|  | 13 | +@generated function dualize(::Type{T}, x::StaticArray) where T | 
|  | 14 | +    N = length(x) | 
|  | 15 | +    dx = Expr(:tuple, [:(Dual{T}(x[$i], chunk, Val{$i}())) for i in 1:N]...) | 
|  | 16 | +    V = StaticArrays.similar_type(x, Dual{T,eltype(x),N}) | 
|  | 17 | +    return quote | 
|  | 18 | +        chunk = Chunk{$N}() | 
|  | 19 | +        $(Expr(:meta, :inline)) | 
|  | 20 | +        return $V($(dx)) | 
|  | 21 | +    end | 
|  | 22 | +end | 
|  | 23 | + | 
|  | 24 | +@inline static_dual_eval(::Type{T}, f, x::StaticArray) where T = f(dualize(T, x)) | 
|  | 25 | + | 
|  | 26 | +function LinearAlgebra.eigvals(A::Symmetric{<:Dual{Tg,T,N}, <:StaticArrays.StaticMatrix}) where {Tg,T<:Real,N} | 
|  | 27 | +    λ,Q = eigen(Symmetric(value.(parent(A)))) | 
|  | 28 | +    parts = ntuple(j -> diag(Q' * getindex.(partials.(A), j) * Q), N) | 
|  | 29 | +    Dual{Tg}.(λ, tuple.(parts...)) | 
|  | 30 | +end | 
|  | 31 | + | 
|  | 32 | +function LinearAlgebra.eigen(A::Symmetric{<:Dual{Tg,T,N}, <:StaticArrays.StaticMatrix}) where {Tg,T<:Real,N} | 
|  | 33 | +    λ = eigvals(A) | 
|  | 34 | +    _,Q = eigen(Symmetric(value.(parent(A)))) | 
|  | 35 | +    parts = ntuple(j -> Q*_lyap_div!(Q' * getindex.(partials.(A), j) * Q - Diagonal(getindex.(partials.(λ), j)), value.(λ)), N) | 
|  | 36 | +    Eigen(λ,Dual{Tg}.(Q, tuple.(parts...))) | 
|  | 37 | +end | 
|  | 38 | + | 
|  | 39 | +# Gradient | 
|  | 40 | +@inline ForwardDiff.gradient(f, x::StaticArray)                      = vector_mode_gradient(f, x) | 
|  | 41 | +@inline ForwardDiff.gradient(f, x::StaticArray, cfg::GradientConfig) = gradient(f, x) | 
|  | 42 | +@inline ForwardDiff.gradient(f, x::StaticArray, cfg::GradientConfig, ::Val) = gradient(f, x) | 
|  | 43 | + | 
|  | 44 | +@inline ForwardDiff.gradient!(result::Union{AbstractArray,DiffResult}, f, x::StaticArray) = vector_mode_gradient!(result, f, x) | 
|  | 45 | +@inline ForwardDiff.gradient!(result::Union{AbstractArray,DiffResult}, f, x::StaticArray, cfg::GradientConfig) = gradient!(result, f, x) | 
|  | 46 | +@inline ForwardDiff.gradient!(result::Union{AbstractArray,DiffResult}, f, x::StaticArray, cfg::GradientConfig, ::Val) = gradient!(result, f, x) | 
|  | 47 | + | 
|  | 48 | +@generated function extract_gradient(::Type{T}, y::Real, x::S) where {T,S<:StaticArray} | 
|  | 49 | +    result = Expr(:tuple, [:(partials(T, y, $i)) for i in 1:length(x)]...) | 
|  | 50 | +    return quote | 
|  | 51 | +        $(Expr(:meta, :inline)) | 
|  | 52 | +        V = StaticArrays.similar_type(S, valtype($y)) | 
|  | 53 | +        return V($result) | 
|  | 54 | +    end | 
|  | 55 | +end | 
|  | 56 | + | 
|  | 57 | +@inline function ForwardDiff.vector_mode_gradient(f, x::StaticArray) | 
|  | 58 | +    T = typeof(Tag(f, eltype(x))) | 
|  | 59 | +    return extract_gradient(T, static_dual_eval(T, f, x), x) | 
|  | 60 | +end | 
|  | 61 | + | 
|  | 62 | +@inline function ForwardDiff.vector_mode_gradient!(result, f, x::StaticArray) | 
|  | 63 | +    T = typeof(Tag(f, eltype(x))) | 
|  | 64 | +    return extract_gradient!(T, result, static_dual_eval(T, f, x)) | 
|  | 65 | +end | 
|  | 66 | + | 
|  | 67 | +# Jacobian | 
|  | 68 | +@inline ForwardDiff.jacobian(f, x::StaticArray) = vector_mode_jacobian(f, x) | 
|  | 69 | +@inline ForwardDiff.jacobian(f, x::StaticArray, cfg::JacobianConfig) = jacobian(f, x) | 
|  | 70 | +@inline ForwardDiff.jacobian(f, x::StaticArray, cfg::JacobianConfig, ::Val) = jacobian(f, x) | 
|  | 71 | + | 
|  | 72 | +@inline ForwardDiff.jacobian!(result::Union{AbstractArray,DiffResult}, f, x::StaticArray) = vector_mode_jacobian!(result, f, x) | 
|  | 73 | +@inline ForwardDiff.jacobian!(result::Union{AbstractArray,DiffResult}, f, x::StaticArray, cfg::JacobianConfig) = jacobian!(result, f, x) | 
|  | 74 | +@inline ForwardDiff.jacobian!(result::Union{AbstractArray,DiffResult}, f, x::StaticArray, cfg::JacobianConfig, ::Val) = jacobian!(result, f, x) | 
|  | 75 | + | 
|  | 76 | +@generated function extract_jacobian(::Type{T}, ydual::StaticArray, x::S) where {T,S<:StaticArray} | 
|  | 77 | +    M, N = length(ydual), length(x) | 
|  | 78 | +    result = Expr(:tuple, [:(partials(T, ydual[$i], $j)) for i in 1:M, j in 1:N]...) | 
|  | 79 | +    return quote | 
|  | 80 | +        $(Expr(:meta, :inline)) | 
|  | 81 | +        V = StaticArrays.similar_type(S, valtype(eltype($ydual)), Size($M, $N)) | 
|  | 82 | +        return V($result) | 
|  | 83 | +    end | 
|  | 84 | +end | 
|  | 85 | + | 
|  | 86 | +@inline function ForwardDiff.vector_mode_jacobian(f, x::StaticArray) | 
|  | 87 | +    T = typeof(Tag(f, eltype(x))) | 
|  | 88 | +    return extract_jacobian(T, static_dual_eval(T, f, x), x) | 
|  | 89 | +end | 
|  | 90 | + | 
|  | 91 | +function extract_jacobian(::Type{T}, ydual::AbstractArray, x::StaticArray) where T | 
|  | 92 | +    result = similar(ydual, valtype(eltype(ydual)), length(ydual), length(x)) | 
|  | 93 | +    return extract_jacobian!(T, result, ydual, length(x)) | 
|  | 94 | +end | 
|  | 95 | + | 
|  | 96 | +@inline function ForwardDiff.vector_mode_jacobian!(result, f, x::StaticArray) | 
|  | 97 | +    T = typeof(Tag(f, eltype(x))) | 
|  | 98 | +    ydual = static_dual_eval(T, f, x) | 
|  | 99 | +    result = extract_jacobian!(T, result, ydual, length(x)) | 
|  | 100 | +    result = extract_value!(T, result, ydual) | 
|  | 101 | +    return result | 
|  | 102 | +end | 
|  | 103 | + | 
|  | 104 | +@inline function ForwardDiff.vector_mode_jacobian!(result::ImmutableDiffResult, f, x::StaticArray) | 
|  | 105 | +    T = typeof(Tag(f, eltype(x))) | 
|  | 106 | +    ydual = static_dual_eval(T, f, x) | 
|  | 107 | +    result = DiffResults.jacobian!(result, extract_jacobian(T, ydual, x)) | 
|  | 108 | +    result = DiffResults.value!(d -> value(T,d), result, ydual) | 
|  | 109 | +    return result | 
|  | 110 | +end | 
|  | 111 | + | 
|  | 112 | +# Hessian | 
|  | 113 | +ForwardDiff.hessian(f, x::StaticArray) = jacobian(y -> gradient(f, y), x) | 
|  | 114 | +ForwardDiff.hessian(f, x::StaticArray, cfg::HessianConfig) = hessian(f, x) | 
|  | 115 | +ForwardDiff.hessian(f, x::StaticArray, cfg::HessianConfig, ::Val) = hessian(f, x) | 
|  | 116 | + | 
|  | 117 | +ForwardDiff.hessian!(result::AbstractArray, f, x::StaticArray) = jacobian!(result, y -> gradient(f, y), x) | 
|  | 118 | + | 
|  | 119 | +ForwardDiff.hessian!(result::MutableDiffResult, f, x::StaticArray) = hessian!(result, f, x, HessianConfig(f, result, x)) | 
|  | 120 | + | 
|  | 121 | +ForwardDiff.hessian!(result::ImmutableDiffResult, f, x::StaticArray, cfg::HessianConfig) = hessian!(result, f, x) | 
|  | 122 | +ForwardDiff.hessian!(result::ImmutableDiffResult, f, x::StaticArray, cfg::HessianConfig, ::Val) = hessian!(result, f, x) | 
|  | 123 | + | 
|  | 124 | +function ForwardDiff.hessian!(result::ImmutableDiffResult, f, x::StaticArray) | 
|  | 125 | +    T = typeof(Tag(f, eltype(x))) | 
|  | 126 | +    d1 = dualize(T, x) | 
|  | 127 | +    d2 = dualize(T, d1) | 
|  | 128 | +    fd2 = f(d2) | 
|  | 129 | +    val = value(T,value(T,fd2)) | 
|  | 130 | +    grad = extract_gradient(T,value(T,fd2), x) | 
|  | 131 | +    hess = extract_jacobian(T,partials(T,fd2), x) | 
|  | 132 | +    result = DiffResults.hessian!(result, hess) | 
|  | 133 | +    result = DiffResults.gradient!(result, grad) | 
|  | 134 | +    result = DiffResults.value!(result, val) | 
|  | 135 | +    return result | 
|  | 136 | +end | 
|  | 137 | + | 
|  | 138 | +end | 
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