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Fix tuple behavior in pushforward_function and pullback_function #100

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Fix tuple behavior in pushforward_function and pullback_function #100

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49 changes: 32 additions & 17 deletions src/AbstractDifferentiation.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -162,18 +162,22 @@ function pushforward_function(
f,
xs...,
)
return (ds) -> begin
return jacobian(lowest(ab), (xds...,) -> begin
if ds isa Tuple
@assert length(xs) == length(ds)
newxs = xs .+ ds .* xds
return f(newxs...)
else
newx = only(xs) + ds * only(xds)
return f(newx)
end
end, _zero.(xs, ds)...)
function _pf(ds::Tuple)
function _step(xds...)
@assert length(xs) == length(ds)
newxs = xs .+ ds .* xds
return f(newxs...)
end
return jacobian(lowest(ab), _step, _zero.(xs, ds)...)
end
function _pf(ds)
function _step(xds)
newx = only(xs) + ds * xds
return f(newx)
end
return jacobian(lowest(ab), _step, _zero(only(xs), ds))
end
return _pf
end
function value_and_pushforward_function(
ab::AbstractBackend,
Expand Down Expand Up @@ -221,18 +225,29 @@ end
end

function pullback_function(ab::AbstractBackend, f, xs...)
return (ws) -> begin
return gradient(lowest(ab), (xs...,) -> begin
vs = f(xs...)
if ws isa Tuple
function _pb(ws::Tuple)
function _dotwithoutput(_xs...)
vs = f(_xs...)
if vs isa Tuple
@assert length(vs) == length(ws)
return sum(Base.splat(_dot), zip(ws, vs))
else
return _dot(vs, ws)
@assert 1 == length(ws)
return sum(Base.splat(_dot), zip(first(ws), vs))
end
end, xs...)
end
return gradient(lowest(ab), _dotwithoutput, xs...)
end
function _pb(ws)
function _dotwithoutput(_xs...)
vs = f(_xs...)
return _dot(vs, ws)
end
return gradient(lowest(ab), _dotwithoutput, xs...)
end
return _pb
end

function value_and_pullback_function(
ab::AbstractBackend,
f,
Expand Down