succ[a][#succ[a] + 1] = b
end
-function DAG:setInput(i)
- self.sorted = nil
- if torch.type(i) == 'table' then
- self.inputModules = i
- for _, m in ipairs(i) do
- if not self.pred[m] and not self.succ[m] then
- self:add(m)
- end
+-- Apply f on t recursively; use the corresponding a1 and a2 elements
+-- (i.e. same keys) as second and third parameters to f when
+-- available; return the results from f, organized in a similarly
+-- nested table.
+function DAG:applyOnModules(f, t, a1, a2)
+ if torch.type(t) == 'table' then
+ local result = {}
+ for k, s in pairs(t) do
+ result[k] = self:applyOnModules(f, s, a1 and a1[k], a2 and a2[k])
end
+ return result
else
- self:setInput({ i })
+ return f(t, a1, a2)
end
end
+function DAG:setInput(i)
+ self.sorted = nil
+ self.inputModules = i
+ self:applyOnModules(
+ function(m)
+ if not self.succ[m] or #self.succ[m] == 0 then
+ error('Input modules must have outgoing edges.')
+ end
+ if self.pred[m] and #self.pred[m] > 0 then
+ error('Input modules cannog have incoming edges.')
+ end
+ end,
+ self.inputModules
+ )
+end
+
function DAG:setOutput(o)
self.sorted = nil
- if torch.type(o) == 'table' then
- self.outputModules = o
- for _, m in ipairs(o) do
- if not self.pred[m] and not self.succ[m] then
- self:add(m)
+ self.outputModules = o
+ self:applyOnModules(
+ function(m)
+ if not self.pred[m] or #self.pred[m] == 0 then
+ error('Output module must have incoming edges.')
end
- end
- else
- self:setOutput({ o })
- end
+ if self.succ[m] and #self.succ[m] > 0 then
+ error('Output module cannot have outgoing edges.')
+ end
+ end,
+ self.outputModules
+ )
end
function DAG:sort()
local distance = {}
- for _, a in pairs(self.inputModules) do
- distance[a] = 1
- end
+ self:applyOnModules(function(m) distance[m] = 1 end, self.inputModules)
local nc
function DAG:updateOutput(input)
self:sort()
- if #self.inputModules == 1 then
- self.inputModules[1]:updateOutput(input)
- else
- for i, d in ipairs(self.inputModules) do
- d:updateOutput(input[i])
- end
- end
+ self:applyOnModules(function(m, i) m:updateOutput(i) end, self.inputModules, input)
for _, d in ipairs(self.sorted) do
if self.pred[d] then
end
end
- if #self.outputModules == 1 then
- self.output = self.outputModules[1].output
- else
- self.output = { }
- for i, d in ipairs(self.outputModules) do
- self.output[i] = d.output
- end
- end
+ self.output = self:applyOnModules(function(m) return m.output end, self.outputModules)
return self.output
end
function DAG:updateGradInput(input, gradOutput)
self:sort()
+
+ self:applyOnModules(
+ function(m, i, go) m:updateGradInput(i, go) end,
+ self.outputModules, input, gradOutput
+ )
+
+ for k = self.sorted, 1, -1 do
+ local m = sorted[k]
+ if self.succ[d] then
+ if #self.succ[d] == 1 then
+ d:updateGradInput(self.succ[d][1].gradInput)
+ elseif #self.succ[d] > 1 then
+ local sum
+ for k = 1, #self.succ[d] do
+ if sum then
+ sum:add(self.succ[d][k].gradInput)
+ else
+ sum = self.succ[d][k].gradInput:clone()
+ end
+ end
+ d:updateGradInput(sum)
+ end
+ end
+ end
+
+ self.gradInput = self:applyOnModules(function(m) return m.gradInput end, self.inputModules)
+
+ return self.gradInput
end
return DAG