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added ConvLSTM with untied first step
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--[[ | ||
Convolutional LSTM for short term visual cell | ||
inputSize - number of input feature planes | ||
outputSize - number of output feature planes | ||
rho - recurrent sequence length | ||
kc - convolutional filter size to convolve input | ||
km - convolutional filter size to convolve cell; usually km > kc | ||
First step is untied. | ||
--]] | ||
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require 'ConvLSTM' | ||
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local UntiedConvLSTM, parent = torch.class('nn.UntiedConvLSTM', 'nn.ConvLSTM') | ||
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function UntiedConvLSTM:__init(inputSize, outputSize, rho, kc, km, stride, batchSize) | ||
parent.__init(self, inputSize, outputSize, rho, kc, km, stride, batchSize) | ||
self.untiedModule = self:buildModelUntied() | ||
end | ||
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function UntiedConvLSTM:buildGateUntied() | ||
-- Note : Input is : input(t) | ||
local gate = nn.Sequential() | ||
gate:add(nn.SpatialConvolution(self.inputSize, self.outputSize, self.kc, self.kc, self.stride, self.stride, self.padc, self.padc)) | ||
gate:add(nn.Sigmoid()) | ||
return gate | ||
end | ||
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function UntiedConvLSTM:buildCellGateUntied() | ||
local cellGate = nn.Sequential() | ||
cellGate:add(nn.SpatialConvolution(self.inputSize, self.outputSize, self.kc, self.kc, self.stride, self.stride, self.padc, self.padc)) | ||
cellGate:add(nn.Tanh()) | ||
self.cellGateUntied = cellGate | ||
return cellGate | ||
end | ||
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function UntiedConvLSTM:buildModelUntied() | ||
-- Input is : input(t) | ||
local model = nn.Sequential() | ||
self.inputGateUntied = self:buildGateUntied() | ||
self.cellGateUntied = self:buildCellGateUntied() | ||
self.outputGateUntied = self:buildGateUntied() | ||
local concat = nn.ConcatTable() | ||
concat:add(self.inputGateUntied):add(self.cellGateUntied):add(self.outputGateUntied) | ||
model:add(concat) | ||
local cellAct = nn.Sequential() | ||
cellAct:add(nn.NarrowTable(1,2)) | ||
cellAct:add(nn.CMulTable()) | ||
local concat2 = nn.ConcatTable() | ||
concat2:add(cellAct):add(nn.SelectTable(3)) | ||
model:add(concat2) | ||
local tanhcell = nn.Sequential() | ||
tanhcell:add(nn.SelectTable(1)):add(nn.Tanh()) | ||
local concat3 = nn.ConcatTable() | ||
concat3:add(nn.SelectTable(2)):add(tanhcell):add(nn.SelectTable(1)) | ||
model:add(concat3) | ||
model:add(nn.FlattenTable()) | ||
local output = nn.Sequential() | ||
output:add(nn.NarrowTable(1,2)) | ||
output:add(nn.CMulTable()) | ||
local concat4 = nn.ConcatTable() | ||
concat4:add(output):add(nn.SelectTable(3)) | ||
model:add(concat4) | ||
return model | ||
end | ||
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function UntiedConvLSTM:updateOutput(input) | ||
local prevOutput, prevCell | ||
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-- output(t), cell(t) = lstm{input(t), output(t-1), cell(t-1)} | ||
local output, cell | ||
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if self.step == 1 then | ||
if self.batchSize then | ||
self.zeroTensor:resize(self.batchSize,self.outputSize,input:size(3),input:size(4)):zero() | ||
else | ||
self.zeroTensor:resize(self.outputSize,input:size(2),input:size(3)):zero() | ||
end | ||
output, cell = unpack(self.untiedModule:updateOutput(input)) | ||
else | ||
-- previous output and memory of this module | ||
prevOutput = self.outputs[self.step-1] | ||
prevCell = self.cells[self.step-1] | ||
if self.train ~= false then | ||
self:recycle() | ||
local recurrentModule = self:getStepModule(self.step) | ||
-- the actual forward propagation | ||
output, cell = unpack(recurrentModule:updateOutput{input, prevOutput, prevCell}) | ||
else | ||
output, cell = unpack(self.recurrentModule:updateOutput{input, prevOutput, prevCell}) | ||
end | ||
end | ||
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self.outputs[self.step] = output | ||
self.cells[self.step] = cell | ||
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self.output = output | ||
self.cell = cell | ||
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self.step = self.step + 1 | ||
self.gradPrevOutput = nil | ||
self.updateGradInputStep = nil | ||
self.accGradParametersStep = nil | ||
self.gradParametersAccumulated = false | ||
-- note that we don't return the cell, just the output | ||
return self.output | ||
end | ||
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function UntiedConvLSTM:_updateGradInput(input, gradOutput) | ||
assert(self.step > 1, "expecting at least one updateOutput") | ||
local step = self.updateGradInputStep - 1 | ||
assert(step >= 1) | ||
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-- set the output/gradOutput states of current Module | ||
if self.gradPrevOutput then | ||
self._gradOutputs[step] = nn.rnn.recursiveCopy(self._gradOutputs[step], self.gradPrevOutput) | ||
nn.rnn.recursiveAdd(self._gradOutputs[step], gradOutput) | ||
gradOutput = self._gradOutputs[step] | ||
end | ||
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local gradInput | ||
local gradInputTable | ||
local gradCell = (step == self.step-1) and (self.userNextGradCell or self.zeroTensor) or self.gradCells[step] | ||
if step == 1 then | ||
gradInput = self.untiedModule:updateGradInput(input, {gradOutput, gradCell}) | ||
else | ||
local recurrentModule = self:getStepModule(step) | ||
local output = self.outputs[step-1] | ||
local cell = self.cells[step-1] | ||
local inputTable = {input, output, cell} | ||
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-- backward propagate through this step | ||
gradInputTable = recurrentModule:updateGradInput(inputTable, {gradOutput, gradCell}) | ||
gradInput, self.gradPrevOutput, gradCell = unpack(gradInputTable) | ||
end | ||
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self.gradCells[step-1] = gradCell | ||
if self.userPrevOutput then self.userGradPrevOutput = self.gradPrevOutput end | ||
if self.userPrevCell then self.userGradPrevCell = gradCell end | ||
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return gradInput | ||
end | ||
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function UntiedConvLSTM:_accGradParameters(input, gradOutput, scale) | ||
local step = self.accGradParametersStep - 1 | ||
assert(step >= 1) | ||
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-- set the output/gradOutput states of current Module | ||
gradOutput = (step == self.step-1) and gradOutput or self._gradOutputs[step] | ||
gradCell = (step == self.step-1) and (self.userNextGradCell or self.zeroTensor) or self.gradCells[step] | ||
gradOutputTable = {gradOutput, gradCell} | ||
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if step == 1 then | ||
self.untiedModule:accGradParameters(input, gradOutputTable,scale) | ||
else | ||
local recurrentModule = self:getStepModule(step) | ||
local output = self.outputs[step-1] | ||
local cell = self.cells[step-1] | ||
local inputTable = {input, output, cell} | ||
recurrentModule:accGradParameters(inputTable, gradOutputTable,scale) | ||
end | ||
end | ||
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function UntiedConvLSTM:initBias(forgetBias, otherBias) | ||
local fBias = forgetBias or 1 | ||
local oBias = otherBias or 0 | ||
self.inputGate.modules[2].modules[1].bias:fill(oBias) | ||
self.outputGate.modules[2].modules[1].bias:fill(oBias) | ||
self.cellGate.modules[2].modules[1].bias:fill(oBias) | ||
self.forgetGate.modules[2].modules[1].bias:fill(fBias) | ||
self.inputGateUntied.modules[1].bias:fill(oBias) | ||
self.outputGateUntied.modules[1].bias:fill(oBias) | ||
self.cellGateUntied.modules[1].bias:fill(oBias) | ||
end |
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