Initial commit.

diff --git a/graphnn.lua b/graphnn.lua
new file mode 100755 (executable)
index 0000000..a3ee1c1
--- /dev/null
+++ b/graphnn.lua
@@ -0,0 +1,125 @@
+#!/usr/bin/env luajit
+
+require 'torch'
+require 'nn'
+require 'image'
+require 'optim'
+
+----------------------------------------------------------------------
+
+local Graph, parent = torch.class('nn.Graph', 'nn.Container')
+
+function Graph:__init()
+   parent.__init(self)
+   self.pred = {}
+   self.succ = {}
+end
+
+function Graph:addEdge(a, b)
+   local pred, succ = self.pred, self.succ
+   if not pred[a] and not succ[a] then
+      self:add(a)
+   end
+   if not pred[b] and not succ[b] then
+      self:add(b)
+   end
+   pred[b] = pred[b] or {}
+   pred[b][#pred[b] + 1] = a
+   succ[a] = succ[a] or {}
+   succ[a][#succ[a] + 1] = b
+end
+
+function Graph:setInput(i)
+   if torch.type(i) == 'table' then
+      self.input = i
+      for _, m in ipairs(i) do
+         if not self.pred[m] and not self.succ[m] then
+            self:add(m)
+         end
+      end
+   else
+      self:setInput({ i })
+   end
+end
+
+function Graph:setOutput(o)
+   if torch.type(o) == 'table' then
+      self.output = o
+      for _, m in ipairs(o) do
+         if not self.pred[m] and not self.succ[m] then
+            self:add(m)
+         end
+      end
+   else
+      self:setOutput({ o })
+   end
+end
+
+function Graph:order()
+   local distance = {}
+
+   for _, a in pairs(self.input) do
+      distance[a] = 1
+   end
+
+   local nc
+
+   repeat
+      nc = 0
+      for i, isucc in pairs(self.succ) do
+         for _, j in pairs(isucc) do
+            if distance[i] and (not distance[j] or distance[j] < distance[i] + 1) then
+               distance[j] = distance[i] + 1
+               nc = nc + 1
+            end
+         end
+      end
+   until nc == 0
+
+   self.sorted = { }
+   for i, d in pairs(distance) do
+      table.insert(self.sorted, { d, i })
+   end
+
+   table.sort(self.sorted, function(a, b) return a[1] < b[1] end)
+   for i, a in ipairs(self.sorted) do self.sorted[i] = a[2] end
+end
+
+function Graph:print()
+   for i, d in ipairs(self.sorted) do
+      print('#' .. i .. ' -> ' .. torch.type(d))
+   end
+end
+
+function Graph:updateOutput(input)
+   return self.output.output
+end
+
+----------------------------------------------------------------------
+
+a = nn.Linear(10, 10)
+b = nn.ReLU()
+c = nn.Linear(10, 3)
+d = nn.Linear(10, 3)
+e = nn.CMulTable()
+
+--[[
+
+   a -----> b ---> c ---- e ---
+             \           /
+              \--> d ---/
+
+]]--
+
+g = Graph:new()
+
+g:setInput(a)
+g:setOutput(e)
+g:addEdge(c, e)
+g:addEdge(a, b)
+g:addEdge(d, e)
+g:addEdge(b, c)
+g:addEdge(b, d)
+
+g:order()
+g:print(graph)