1 files changed, 156 insertions, 0 deletions
diff --git a/nerv/layer/graph.lua b/nerv/layer/graph.lua
new file mode 100644
index 0000000..68d5f51
--- /dev/null
+++ b/nerv/layer/graph.lua
@@ -0,0 +1,156 @@
+local GraphLayer = nerv.class('nerv.GraphLayer', 'nerv.Layer')
+
+function GraphLayer:__init(id, global_conf, layer_conf)
+    nerv.Layer.__init(self, id, global_conf, layer_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
+
+function GraphLayer:add_prefix(layers, connections)
+    local function ap(name)
+        return self.id .. '.' .. name
+    end
+
+    for layer_type, sublayers in pairs(layers) do
+        local tmp = {}
+        for name, layer_config in pairs(sublayers) do
+            tmp[ap(name)] = layer_config
+        end
+        layers[layer_type] = tmp
+    end
+
+    for i = 1, #connections do
+        local from, to = connections[i][1], connections[i][2]
+        if parse_id(from) ~= '<input>' then
+            connections[i][1] = ap(from)
+        end
+        if parse_id(to) ~= '<output>' then
+            connections[i][2] = ap(to)
+        end
+    end
+end
+
+function GraphLayer:discover(id, layer_repo)
+    if id == '<output>' then
+        id = '<input>'
+    end
+    local layers = self.layers
+    local ref = layers[id]
+    if ref == nil then
+        local layer = layer_repo:get_layer(id)
+        local dim_in, dim_out = layer:get_dim()
+        self.layer_num = self.layer_num + 1
+        ref = {
+            layer = layer,
+            inputs = {},
+            outputs = {},
+            dim_in = dim_in,
+            dim_out = dim_out,
+            id = self.layer_num,
+        }
+        layers[id] = ref
+    end
+    return ref
+end
+
+function GraphLayer:graph_init(layer_repo, connections)
+    local layers = {}
+    layers['<input>'] = {
+        inputs = {},
+        outputs = {},
+        dim_in = self.dim_out,
+        dim_out = self.dim_in,
+        id = 0,
+    }
+    self.layers = layers
+    self.layer_num = 0
+    self.connections = {}
+
+    -- check data dimension between connected ports
+    for _, edge in pairs(connections) do
+        local from, to, time = edge[1], edge[2], edge[3]
+        local id_from, port_from = parse_id(from)
+        local id_to, port_to = parse_id(to)
+        local ref_from = self:discover(id_from, layer_repo)
+        local ref_to = self:discover(id_to, layer_repo)
+        if ref_from.outputs[port_from] ~= nil then
+            nerv.error('%s has already been attached', from)
+        end
+        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
+        if ref_from.id == 0 and ref_to.id == 0 then
+            nerv.error('short-circuit connection between <input> and <output>')
+        end
+        ref_from.outputs[port_from] = true
+        ref_to.inputs[port_to] = true
+        table.insert(self.connections, {ref_from.id, port_from, ref_to.id, port_to, time})
+    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 of layer %s', i, id)
+                end
+            end
+        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, ref in pairs(self.layers) do
+        if id ~= '<input>' then
+            ref.layer:set_attr(name, value)
+        end
+    end
+end
+
+function GraphLayer:get_sublayer(id)
+    if self.layers[id] == nil or id == '<input>' then
+        nerv.error('layer with id %s not found', id)
+    end
+    return self.layers[id].layer
+end
+
+function GraphLayer:get_params()
+    local param_repos = {}
+    for id, ref in pairs(self.layers) do
+        if id ~= '<input>' then
+            table.insert(param_repos, ref.layer:get_params())
+        end
+    end
+    return nerv.ParamRepo.merge(param_repos, self.loc_type)
+end