1 files changed, 118 insertions, 0 deletions
diff --git a/nerv/layer/graph.lua b/nerv/layer/graph.lua
new file mode 100644
index 0000000..83cf810
--- /dev/null
+++ b/nerv/layer/graph.lua
@@ -0,0 +1,118 @@
+local GraphLayer = nerv.class('nerv.GraphLayer', 'nerv.Layer')
+
+function GraphLayer:__init(id, global_conf, layer_conf)
+    self.id = id
+    self.dim_in = layer_conf.dim_in
+    self.dim_out = layer_conf.dim_out
+    self.gconf = global_conf
+    self:graph_init(layer_conf.layer_repo, layer_conf.connections)
+end
+
+local function parse_id(str)
+    local id, port, _
+    _, _, id, port = string.find(str, "([a-zA-Z0-9_.]+)%[([0-9]+)%]")
+    if id == nil or port == nil then
+        _, _, id, port = string.find(str, "(.+)%[([0-9]+)%]")
+        if not (id == "<input>" or id == "<output>") then
+            nerv.error("wrong format of connection id")
+        end
+    end
+    port = tonumber(port)
+    return id, port
+end
+
+local function discover(id, layers, layer_repo)
+    if id == '<output>' then
+        id = '<input>'
+    end
+    local ref = layers[id]
+    if ref == nil then
+        local layer = layer_repo:get_layer(id)
+        local dim_in, dim_out = layer:get_dim()
+        ref = {
+            layer = layer,
+            inputs = {},
+            outputs = {},
+            dim_in = dim_in,
+            dim_out = dim_out,
+        }
+        layers[id] = ref
+    end
+    return ref
+end
+
+function GraphLayer:graph_init(layer_repo, connections)
+    self.connections = connections
+    self.sublayer = nerv.LayerRepo({}, nerv.ParamRepo(), self.gconf)
+
+    -- check data dimension between connected ports
+    local layers = {}
+    layers['<input>'] = {
+        inputs = {},
+        outputs = {},
+        dim_in = self.dim_out,
+        dim_out = self.dim_in,
+    }
+    for _, edge in pairs(self.connections) do
+        local from = edge[1]
+        local to = edge[2]
+        local id_from, port_from = parse_id(from)
+        local id_to, port_to = parse_id(to)
+        local ref_from = discover(id_from, layers, layer_repo)
+        local ref_to = discover(id_to, layers, layer_repo)
+        if ref_to.inputs[port_to] ~= nil then
+            nerv.error('%s has already been attached', to)
+        end
+        if ref_from.dim_out[port_from] ~= ref_to.dim_in[port_to] then
+            nerv.error('mismatching data dimension between %s and %s', from, to)
+        end
+        ref_from.outputs[port_from] = true
+        ref_to.inputs[port_to] = true
+    end
+
+    -- check dangling ports
+    for id, ref in pairs(layers) do
+        if id ~= '<input>' then
+            for i = 1, #ref.dim_in do
+                if ref.inputs[i] == nil then
+                    nerv.error('dangling input port %d of layer %s', i, id)
+                end
+            end
+            for i = 1, #ref.dim_out do
+                if ref.outputs[i] == nil then
+                   nerv.error('dangling output port %d os layer %s', i, id)
+                end
+            end
+            self.sublayer.layers[id] = ref.layer
+        end
+    end
+    for i = 1, #self.dim_in do
+        if layers['<input>'].outputs[i] == nil then
+            nerv.error('dangling port %d of layer <input>', i)
+        end
+    end
+    for i = 1, #self.dim_out do
+        if layers['<input>'].inputs[i] == nil then
+            nerv.error('dangling port %d of layer <output>', i)
+        end
+    end
+end
+
+function GraphLayer:set_attr(name, value)
+    self[name] = value
+    for id, layer in pairs(self.sublayer.layers) do
+        layer:set_attr(name, value)
+    end
+end
+
+function GraphLayer:get_sublayer(id)
+    return self.sublayer:get_layer(id)
+end
+
+function GraphLayer:get_params()
+    local param_repos = {}
+    for id, layer in pairs(self.sublayer.layers) do
+        table.insert(param_repos, layer:get_params())
+    end
+    return nerv.ParamRepo.merge(param_repos)
+end