123 lines
3.0 KiB
Julia
123 lines
3.0 KiB
Julia
export unroll
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type Offset
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name::Symbol
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n::Int
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default::Nullable{Param}
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end
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Offset(name, n) = Offset(name, n, nothing)
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Base.:-(o::Offset) = Offset(o.name, -o.n, o.default)
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function liftloops(ex, params)
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ex = DataFlow.normedges(ex)
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MacroTools.postwalk(ex) do ex
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@capture(ex, x_{n_}) || return ex
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:($(Offset(x,n))($x))
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end
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end
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function hasloops(model)
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g = graph(model)
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g == nothing && return false
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iscyclic(g) && return true
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result = false
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map(m -> hasloops(m) && (result = true), g)
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return result
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end
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function atomise(model)
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postwalk(graph(model)) do v
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hasloops(value(v)) || return v
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spliceinputs(atomise(value(v)), inputs(v)...)
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end
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end
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function collect_state(v::IVertex)
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state = typeof(v)[]
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offset = Int[]
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default = Param[]
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prewalk!(v) do v
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isa(value(v), Offset) || return v
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if (i = findfirst(state, v[1])) == 0
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push!(state, v[1])
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push!(offset, max(0, -value(v).n))
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push!(default, get(value(v).default))
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else
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offset[i] = max(offset[i], -value(v).n)
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end
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v
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end
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return state, offset, default
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end
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hiddeninput(n) = vertex(Split(n), inputnode(1))
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function create_steps(v::IVertex, n; seq = true, stateful = true)
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[(stateful ? bumpinputs : copy)(seq ? spliceinputs(v, hiddeninput(i)) : v) for i = 1:n]
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end
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function getvar(n, step, steps, offset, default; stateful = true)
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if stateful && step < 1
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hiddeninput(sum(offset[1:n-1]) + 1 - step)
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elseif step ∉ 1:length(steps)
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constant(default[n])
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else
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steps[step][1,n]
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end
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end
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function stateout(steps, offset, default)
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outs = []
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defaults = []
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for i = 1:length(offset), j = 1:offset[i]
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push!(outs, getvar(i, length(steps)-j+1, steps, offset, default))
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push!(defaults, default[i])
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end
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group(outs...), defaults
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end
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function unrollgraph(v::IVertex, n; seq = true, stateful = true)
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state, offset, default = collect_state(v)
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v = group(group(state...), v)
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steps = create_steps(v, n, seq = seq, stateful = stateful)
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for i = 1:n
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vars = inputs(steps[i][1])
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postwalk!(steps[i]) do v
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isa(value(v), Offset) || return v
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varid = findfirst(vars,v[1])
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getvar(varid, value(v).n + i, steps, offset, default, stateful = stateful)
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end
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end
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out = group(map(x->x[2], steps)...)
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if stateful
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state, defaults = stateout(steps, offset, default)
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group(state,out), map(Flux.state, defaults)
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else
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out, []
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end
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end
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unrollgraph(m, n; kws...) = unrollgraph(atomise(m), n; kws...)
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# TODO: perhaps split into SeqModel + StatefulModel
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type Unrolled <: Model
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model
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graph::IVertex{Any}
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state::Vector{Any}
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stateful::Bool
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steps::Int
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end
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(m::Unrolled)(xs...) = interpret(reifyparams(m.graph), xs...)
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graph(u::Unrolled) = u.graph
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function unroll(model, n; seq = true, stateful = true)
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graph, state = unrollgraph(model, n; seq = seq, stateful = stateful)
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seq || stateful ? Unrolled(model, graph, state, stateful, n) : Capacitor(graph)
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end
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flip(model) = Capacitor(map(x -> isa(x, Offset) ? -x : x, atomise(model)))
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