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Suppose I have a net

SeedRandom[1234];
net = NetInitialize@NetGraph[{ReshapeLayer[{4, 8}], 
                              BasicRecurrentLayer[8], SequenceLastLayer[], 
                              CatenateLayer[], 8, Ramp, 8}, 
                             {NetPort["history"] -> 1 -> 2 -> 3 -> 4, 
                              NetPort["Input1"] -> 4 -> 5 -> 6 -> 7}, 
                             "history" -> 8*4, 
                             "Input1" -> 40]

enter image description here

This is the Input1,it has 20 examples.

data = RandomReal[1, {20, 40}];

Because of the output of this net has 8-dims Output.

Four past outputs constitute the 32-dims vector and the net use this vector and Input1 to predict next history.

Assuming at time 1,there is no history and history is all zero.

time 1:

net[<|"Input1" -> data[[1]], "history" ->      ConstantArray[0, 8*4]|>]

time 2:

net[<|"Input1" -> data[[2]], "history" -> Join[ConstantArray[0, 8*3], %]|>]

time 3:

net[<|"Input1" -> data[[3]], "history" -> Join[ConstantArray[0, 8*2], %%, %]|>]

time 4:

net[<|"Input1" -> data[[4]], "history" -> Join[ConstantArray[0, 8*1], %%%, %%, %]|>]

time 5:

net[<|"Input1" -> data[[5]], "history" -> Join[%%%%, %%%, %%, %]|>]

time 6:

net[<|"Input1" -> data[[6]], "history" -> Join[%%%%, %%%, %%, %]|>]

enter image description here

...

time 20:

net[<|"Input1" -> data[[20]], "history" -> Join[%%%%, %%%, %%, %]|>]

I try this code but it can not be combined with other codes well.

And it mismatch the result at time 6

out = ConstantArray[0, {20, 8}];
out[[1]] = net[<|"Input1" -> data[[1]], "history" -> ConstantArray[0, 8*4]|>];
out[[2]] = net[<|"Input1" -> data[[2]], "history" -> Join[ConstantArray[0, 8*3], %]|>];
out[[3]] = net[<|"Input1" -> data[[3]], "history" -> Join[ConstantArray[0, 8*2], %%, %]|>];
out[[4]] = net[<|"Input1" -> data[[4]], "history" -> Join[ConstantArray[0, 8*1], %%%, %%, %]|>];
Do[out[[i]] = net[<|"Input1" -> data[[i]], 
                    "history" -> Join[%%%%, %%%, %%, %]|>], {i, 5, 20}]

enter image description here

So is there a nice way or a functional style to implement this and got the Output from time 1 to 20?

How can trace the recent four historical results,FoldList can do it?

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4
  • 1
    $\begingroup$ Nice question, looks like a task for SequenceFold, surprised there's no answer yet. +1 $\endgroup$
    – LLlAMnYP
    Commented Jun 22, 2017 at 14:52
  • $\begingroup$ @LLlAMnYP Nice to hear that :) $\endgroup$
    – partida
    Commented Jun 22, 2017 at 15:12
  • $\begingroup$ Self-answers are encouraged here. If you think you've achieved your goals, why not transfer your update to a proper answer? $\endgroup$
    – LLlAMnYP
    Commented Jun 23, 2017 at 8:04
  • $\begingroup$ @LLlAMnYP right ,thank you $\endgroup$
    – partida
    Commented Jun 23, 2017 at 11:01

1 Answer 1

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Thanks LLlAMnYP,I try SequenceFoldList and find it can generate interesting result.

SequenceFoldList[f, {0, 0, 0, 0}, Range[5], 4] // Column

enter image description here

So I am sure it can be used in here.

Module[{i = 1}, Drop[#, 4] &@
   SequenceFoldList[
     net[<|"Input1" -> data[[i++]], 
           "history" -> Flatten@{##}|>] &, 
     {ConstantArray[0, 8], ConstantArray[0, 8], ConstantArray[0, 8],ConstantArray[0, 8]}, 
     Range[Length@data-1], 4]] // MatrixForm

enter image description here

It got a correct result.

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