support multiple nodal inputs

main.lua

@@ -829,7 +829,7 @@ while true do
     if enable_network and get_state() == 'playing' or ingame_paused then
         local choose = deterministic and argmax2 or rchoice2
 
-        local outputs = network:forward(X)
+        local outputs = network:forward({[nn_x]=X})
 
         -- TODO: predict the *rewards* of all possible actions?
         --       that's how DQN seems to work anyway.

nn.lua

@@ -374,12 +374,14 @@ function Model:reset()
     end
 end
 
-function Model:forward(X)
+function Model:forward(inputs)
     local values = {}
     local outputs = {}
     for i, node in ipairs(self.nodes) do
         --print(i, node.name)
         if contains(self.nodes_in, node) then
+            local X = inputs[node]
+            assert(X ~= nil, ("missing input for node %s"):format(node.name))
             values[node] = node:_propagate({X})
         else
             values[node] = node:propagate(values)