add graphviz printing and stuff

main.lua

@@ -682,6 +682,7 @@ end
 local function init()
     network = make_network(input_size, learn_start_select and 8 or 6)
     network:reset()
+    network:print()
     print("parameters:", network.n_param)
 
     emu.poweron()

nn.lua

@@ -700,6 +700,7 @@ end
 function Model:reset()
     self.n_param = 0
     for _, node in ipairs(self.nodes) do
+        print(node.name, node:get_size())
         node:init_weights()
         self.n_param = self.n_param + node:get_size()
     end
@@ -730,7 +731,15 @@ function Model:cleargrad()
 end
 
 function Model:print()
-    error("TODO") -- TODO
+    print("digraph G {")
+    for _, parent in ipairs(self.nodes) do
+        if #parent.children then
+            for _, child in ipairs(parent.children) do
+                print('\t'..parent.name..'->'..child.name..';')
+            end
+        end
+    end
+    print('}')
 end
 
 function Model:collect()