Update.

[dagnn.git] / dagnn.lua

diff --git a/dagnn.lua b/dagnn.lua
index 65a30e2..a6414b3 100755 (executable)
--- a/dagnn.lua
+++ b/dagnn.lua
@@ -25,26 +25,46 @@ function DAG:addEdge(a, b)
    succ[a][#succ[a] + 1] = b
 end
 
-function DAG:applyOnModules(f, t1, t2)
-   if torch.type(t1) == 'table' then
+-- 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(t1) do
-         result[k] = self:applyOnModules(f, s, t2 and t2[k])
+      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
-      return f(t1, t2)
+      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) or (self.pred[m] and #self.pred[m] > 0) then
+            error('Invalid input edges.')
+         end
+      end,
+      self.inputModules
+   )
 end
 
 function DAG:setOutput(o)
    self.sorted = nil
    self.outputModules = o
+   self:applyOnModules(
+      function(m)
+         if (not self.pred[m] or #self.pred[m] == 0) or (self.succ[m] and #self.succ[m] > 0) then
+            error('Invalid output edges.')
+         end
+      end,
+      self.outputModules
+   )
 end
 
 function DAG:sort()
@@ -113,6 +133,31 @@ 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