# Evaluate variable-length input array RNN in Julia Flux

**URL:** <https://discourse.julialang.org/t/evaluate-variable-length-input-array-rnn-in-julia-flux/82475>\
**Category:** General Usage\
**Tags:** question, flux, rnn\
**Created:** [June 9, 2022, 7:51am UTC](https://discourse.julialang.org/t/evaluate-variable-length-input-array-rnn-in-julia-flux/82475 "2022-06-09T07:51:55Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![HerAdri](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/heradri/32/5816_2.png) [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Post date:** [June 9, 2022, 7:51am UTC](https://discourse.julialang.org/t/evaluate-variable-length-input-array-rnn-in-julia-flux/82475/1 "2022-06-09T07:51:55Z")

</div>

How to create a vector of a matrice for variable sequence length data to evaluate untrained RNN?  
Following the idea developed in these [[link1](https://quabr.com/67934386/evaluate-simple-rnn-in-julia-flux), [link2](https://stackoverflow.com/questions/67934386/evaluate-simple-rnn-in-julia-flux)] it is possible to carry out the evaluation for a vector;

```julia
using Flux

simple_rnn = Flux.RNN(1, 1, (x -> x))

#simple_rnn.([1, 2, 3])

v = Vector{Vector{Float32}}([[1], [2], [3]])

simple_rnn.(v)

v=[2,4,5,6]

vv=[Vector{Float32}([i]) for i in v]

simple_rnn.(vv)

seq = [Vector{Float32}([i]) for i = rand(10)]

simple_rnn.(seq)

```

but for the matrix for variable sequence length data, I get the following alert:

```julia
julia> b=[[1, 2, 3],[2,4,5,6],[6.0, 7.0, 7.0, 10.0, 7.0, 8.0]]
3-element Vector{Vector{Float64}}:
[1.0, 2.0, 3.0]
[2.0, 4.0, 5.0, 6.0]
[6.0, 7.0, 7.0, 10.0, 7.0, 8.0]

julia> c=[[Vector{Float32}([j]) for j in i] for i in b]
3-element Vector{Vector{Vector{Float32}}}:
[[1.0], [2.0], [3.0]]
[[2.0], [4.0], [5.0], [6.0]]
[[6.0], [7.0], [7.0], [10.0], [7.0], [8.0]]

simple_rnn.(c)
ERROR: MethodError: no method matching (::Flux.RNNCell{var"#5#6", Matrix{Float32}, Vector{Float32}, Matrix{Float32}})(::
Matrix{Float32}, ::Vector{Vector{Float32}})
Closest candidates are:
 (::Flux.RNNCell{F, A, V, <:AbstractMatrix{T}})(::Any, ::Union{AbstractMatrix{T}, AbstractVector{T}, Flux.OneHotArray})
where {F, A, V, T} at C:\Users\Hermesr\.julia\packages\Flux\js6mP\src\layers\recurrent.jl:138
Stacktrace:
[1] (::Flux.Recur{Flux.RNNCell{var"#5#6", Matrix{Float32}, Vector{Float32}, Matrix{Float32}}, Matrix{Float32}})(x::Vect
or{Vector{Float32}})
. . .

[7] top-level scope
 @ REPL[24]:1
[8] top-level scope
 @ C:\Users\Hermesr\.julia\packages\CUDA\qAl31\src\initialization.jl:52

```

If the solution is possible by correctly interpreting the error alert shown by Julia. I would be very grateful if you could enlighten me!!!

---

<div class="post-metadata">

**Author:** ![skleinbo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/skleinbo/32/36080_2.png) [@skleinbo](https://discourse.julialang.org/u/skleinbo)\
**Post date:** [June 9, 2022, 8:47am UTC](https://discourse.julialang.org/t/evaluate-variable-length-input-array-rnn-in-julia-flux/82475/2 "2022-06-09T08:47:48Z")

</div>

```julia
julia> map(c) do v
         reset!(simple_rnn)
         simple_rnn.(v)
       end
┌ Warning: Broadcasting is not safe to use with RNNs, as it does not guarantee an iteration order.
│ Re-writing this as a comprehension would be better.
│ caller = (::var"#21#22")(v::Vector{Vector{Float32}}) at REPL[46]:3
└ @ Main ./REPL[46]:3
3-element Vector{Vector{Vector{Float32}}}:
 [[-0.32932267], [-1.0383314], [-2.1850915]]
 [[-0.65864533], [-2.0766628], [-4.04086], [-6.6347656]]
 [[-1.9759359], [-4.583375], [-7.58957], [-12.04347], [-16.190538], [-21.30114]]

```

I suppose you want the `reset!` here to not carry over state between batches.

Note the warning though. The broadcast `.` should really be written as `[simple_rnn(x) for x in v]` to guarantee order.

---

<div class="post-metadata">

**Author:** ![HerAdri](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/heradri/32/5816_2.png) [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Post date:** [June 9, 2022, 6:55pm UTC](https://discourse.julialang.org/t/evaluate-variable-length-input-array-rnn-in-julia-flux/82475/3 "2022-06-09T18:55:49Z")

</div>

> [@HerAdri](#):
>
> ```julia
> simple_rnn = Flux.RNN(1, 1, (x -> x))
> 
> ```

```julia
using Flux
simple_rnn = Flux.RNN(1, 1, (x -> x))

b=[[1, 2, 3],[2,4,5,6],[6.0, 7.0, 7.0, 10.0, 7.0, 8.0]]

 c=[[Vector{Float32}([j]) for j in i] for i in b]

map(c) do v
                Flux.reset!(simple_rnn)
                simple_rnn.(v)
       end

 map(c) do v
                Flux.reset!(simple_rnn)
                [simple_rnn(x) for x in v]
       end

```

Why should I declare Flux.reset! In the code?  
And not just reset! When at the beginning Flux has been declared(loaded)  
this also happens to me with Flux.params, etc.

---

<div class="post-metadata">

**Author:** ![skleinbo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/skleinbo/32/36080_2.png) [@skleinbo](https://discourse.julialang.org/u/skleinbo)\
**Post date:** [June 10, 2022, 7:18am UTC](https://discourse.julialang.org/t/evaluate-variable-length-input-array-rnn-in-julia-flux/82475/4 "2022-06-10T07:18:15Z")

</div>

Because `Flux` doesn’t export these symbols. If you want them in the importing namespace, do

```julia
using Flux: reset!, params, [...]

```

---

<div class="post-metadata">

**Author:** ![HerAdri](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/heradri/32/5816_2.png) [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Post date:** [June 20, 2022, 1:19pm UTC](https://discourse.julialang.org/t/evaluate-variable-length-input-array-rnn-in-julia-flux/82475/5 "2022-06-20T13:19:59Z")

</div>

Is this a Flux bug?  
Or have I not done something right?

```julia
using Flux
simple_rnn = Flux.RNN(1, 1, (x -> x))
###

function eval_model(x)
    ax=[Vector{Float32}[[j] for j in i] for i in x]
    out = map(ax) do v
        Flux.reset!(simple_rnn)
        a=[simple_rnn(x) for x in v][end]
        reduce(vcat,a)
    end
out
end
eval_model(data)
loss(x, y) = abs(sum((eval_model(x) .-y)))
loss(data, labels)
loss.(data, labels)

###[A Basic RNN](https://learningjulia.com/2019/10/11/a-basic-rnn.html)
ps = Flux.params(simple_rnn)
opt = Flux.ADAM()

println("Training loss before = ", sum(loss.(data, labels)))
#println("Test loss before = ", sum(loss.(test_data, test_labels)))

# callback function during training
evalcb() = @show(sum(loss.(data, labels)))
using Flux: @epochs
@epochs num_epochs Flux.train!(loss, ps, [(data, labels)], opt, cb = Flux.throttle(evalcb, 1))

[ Info: Epoch 1
ERROR: MethodError: no method matching getindex(::Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, ::UnitRange{Int64})
Stacktrace:
  [1] getobs(data::Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, idx::UnitRange{Int64})
    @ MLUtils C:\Users\Hermesr\.julia\packages\MLUtils\6niiD\src\observation.jl:49
  [2] (::MLUtils.var"#7#8"{UnitRange{Int64}})(x::Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}})
    @ MLUtils C:\Users\Hermesr\.julia\packages\MLUtils\6niiD\src\observation.jl:136
  [3] map
    @ .\tuple.jl:222 [inlined]
  [4] getobs(tup::Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, indices::UnitRange{Int64})
    @ MLUtils C:\Users\Hermesr\.julia\packages\MLUtils\6niiD\src\observation.jl:136
  [5] getobs(subset::MLUtils.ObsView{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, UnitRange{Int64}}, idx::UnitRange{Int64})
    @ MLUtils C:\Users\Hermesr\.julia\packages\MLUtils\6niiD\src\obsview.jl:187
  [6] _getbatch(A::MLUtils.BatchView{Union{}, MLUtils.ObsView{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, UnitRange{Int64}}, Val{nothing}}, obsindices::UnitRange{Int64})
    @ MLUtils C:\Users\Hermesr\.julia\packages\MLUtils\6niiD\src\batchview.jl:147
  [7] getindex(A::MLUtils.BatchView{Union{}, MLUtils.ObsView{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, UnitRange{Int64}}, Val{nothing}}, i::Int64)
    @ MLUtils C:\Users\Hermesr\.julia\packages\MLUtils\6niiD\src\batchview.jl:132
  [8] getobs(data::MLUtils.BatchView{Union{}, MLUtils.ObsView{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, UnitRange{Int64}}, Val{nothing}}, idx::Int64)
    @ MLUtils C:\Users\Hermesr\.julia\packages\MLUtils\6niiD\src\observation.jl:49
  [9] (::MLUtils.var"#38#40")(i::Int64)
    @ MLUtils .\none:0
 [10] iterate(::Base.Generator{UnitRange{Int64}, MLUtils.var"#38#40"})
    @ Base .\generator.jl:47
 [11] iterate(e::MLUtils.DataLoader{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, Random._GLOBAL_RNG, Val{nothing}})
    @ MLUtils C:\Users\Hermesr\.julia\packages\MLUtils\6niiD\src\eachobs.jl:173
 [12] iterate
    @ .\generator.jl:44 [inlined]
 [13] collect(itr::Base.Generator{MLUtils.DataLoader{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, Random._GLOBAL_RNG, Val{nothing}}, Zygote.var"#543#547"{Zygote.Context, var"#33#36"}})
    @ Base .\array.jl:724
 [14] map
    @ .\abstractarray.jl:2896 [inlined]
 [15] ∇map(cx::Zygote.Context, f::var"#33#36", args::MLUtils.DataLoader{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, Random._GLOBAL_RNG, Val{nothing}})
    @ Zygote C:\Users\Hermesr\.julia\packages\Zygote\DkIUK\src\lib\array.jl:184
 [16] _pullback(cx::Zygote.Context, #unused#::typeof(collect), g::Base.Generator{MLUtils.DataLoader{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, Random._GLOBAL_RNG, Val{nothing}}, var"#33#36"})
    @ Zygote C:\Users\Hermesr\.julia\packages\Zygote\DkIUK\src\lib\array.jl:231
 [17] _pullback
    @ c:\projects\Julia Flux\Evaluate simple RNN in Julia Flux.jl:56 [inlined]
 [18] _pullback(ctx::Zygote.Context, f::typeof(eval_model), args::MLUtils.DataLoader{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, Random._GLOBAL_RNG, Val{nothing}})
    @ Zygote C:\Users\Hermesr\.julia\packages\Zygote\DkIUK\src\compiler\interface2.jl:0
 [19] _pullback
    @ c:\projects\Julia Flux\Evaluate simple RNN in Julia Flux.jl:65 [inlined]
 [20] _pullback(::Zygote.Context, ::typeof(loss), ::MLUtils.DataLoader{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, Random._GLOBAL_RNG, Val{nothing}}, ::Vector{Int64})
    @ Zygote C:\Users\Hermesr\.julia\packages\Zygote\DkIUK\src\compiler\interface2.jl:0
 [21] _apply(::Function, ::Vararg{Any})
    @ Core .\boot.jl:814
 [22] adjoint
    @ C:\Users\Hermesr\.julia\packages\Zygote\DkIUK\src\lib\lib.jl:204 [inlined]
 [23] _pullback
    @ C:\Users\Hermesr\.julia\packages\ZygoteRules\AIbCs\src\adjoint.jl:65 [inlined]
 [24] _pullback
    @ C:\Users\Hermesr\.julia\packages\Flux\js6mP\src\optimise\train.jl:120 [inlined]
 [25] _pullback(::Zygote.Context, ::Flux.Optimise.var"#37#40"{typeof(loss), Tuple{MLUtils.DataLoader{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, Random._GLOBAL_RNG, Val{nothing}}, Vector{Int64}}})
    @ Zygote C:\Users\Hermesr\.julia\packages\Zygote\DkIUK\src\compiler\interface2.jl:0
 [26] pullback(f::Function, ps::Zygote.Params{Zygote.Buffer{Any, Vector{Any}}})
    @ Zygote C:\Users\Hermesr\.julia\packages\Zygote\DkIUK\src\compiler\interface.jl:352
 [27] gradient(f::Function, args::Zygote.Params{Zygote.Buffer{Any, Vector{Any}}})
    @ Zygote C:\Users\Hermesr\.julia\packages\Zygote\DkIUK\src\compiler\interface.jl:75
 [28] macro expansion
    @ C:\Users\Hermesr\.julia\packages\Flux\js6mP\src\optimise\train.jl:119 [inlined]
 [29] macro expansion
    @ C:\Users\Hermesr\.julia\packages\ProgressLogging\6KXlp\src\ProgressLogging.jl:328 [inlined]
 [30] train!(loss::Function, ps::Zygote.Params{Zygote.Buffer{Any, Vector{Any}}}, data::Vector{Tuple{MLUtils.DataLoader{Tuple{Base.Iterators.Zip{Tuple{Vector{Vector{Int64}}, Vector{Int64}}}, Vector{Int64}}, Random._GLOBAL_RNG, Val{nothing}}, Vector{Int64}}}, opt::ADAM; cb::Flux.var"#throttled#122"{Flux.var"#throttled#118#123"{Bool, Bool, typeof(evalcb), Int64}})
    @ Flux.Optimise C:\Users\Hermesr\.julia\packages\Flux\js6mP\src\optimise\train.jl:117
 [31] macro expansion
    @ C:\Users\Hermesr\.julia\packages\Flux\js6mP\src\optimise\train.jl:155 [inlined]
 [32] top-level scope
    @ C:\Users\Hermesr\.julia\packages\ProgressLogging\6KXlp\src\ProgressLogging.jl:470

###
data2=zip(data, labels)# 
data1=Flux.DataLoader((data, labels), batchsize=num_epochs)#

```