local DAGLayer = nerv.class("nerv.DAGLayer", "nerv.Layer")
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)
local ref = layers[id]
if id == "<input>" or id == "<output>" then
return nil
end
if ref == nil then
local layer = layer_repo:get_layer(id)
local dim_in, dim_out = layer:get_dim()
ref = {
layer = layer,
inputs = {},
outputs = {},
err_inputs = {},
err_outputs = {},
next_layers = {},
input_len = #dim_in,
output_len = #dim_out,
in_deg = 0,
visited = false
}
layers[id] = ref
end
return ref
end
function DAGLayer:__init(id, global_conf, layer_conf)
local layers = {}
local inputs = {}
local outputs = {}
local dim_in = layer_conf.dim_in
local dim_out = layer_conf.dim_out
local parsed_conn = {}
for from, to in pairs(layer_conf.connections) do
local id_from, port_from = parse_id(from)
local id_to, port_to = parse_id(to)
local ref_from = discover(id_from, layers, layer_conf.sub_layers)
local ref_to = discover(id_to, layers, layer_conf.sub_layers)
local input_dim, output_dim, _
if ref_from and ref_from.outputs[port_from] ~= nil then
nerv.error("%s has already been attached", from)
end
if ref_to and ref_to.inputs[port_to] ~= nil then
nerv.error("%s has already been attached", to)
end
if id_from == "<input>" then
input_dim, _ = ref_to.layer:get_dim()
if dim_in[port_from] ~= input_dim[port_to] then
nerv.error("mismatching data dimension between %s and %s", from, to)
end
inputs[port_from] = {ref_to, port_to}
ref_to.inputs[port_to] = inputs -- just a place holder
elseif id_to == "<output>" then
_, output_dim = ref_from.layer:get_dim()
if output_dim[port_from] ~= dim_out[port_to] then
nerv.error("mismatching data dimension between %s and %s", from, to)
end
outputs[port_to] = {ref_from, port_from}
ref_from.outputs[port_from] = outputs -- just a place holder
else
_, output_dim = ref_from.layer:get_dim()
input_dim, _ = ref_to.layer:get_dim()
if output_dim[port_from] ~= input_dim[port_to] then
nerv.error("mismatching data dimension between %s and %s", from, to)
end
table.insert(parsed_conn,
{{ref_from, port_from}, {ref_to, port_to}})
table.insert(ref_from.next_layers, ref_to) -- add edge
ref_to.in_deg = ref_to.in_deg + 1 -- increase the in-degree of the target layer
end
end
-- topology sort
local queue = {}
local l = 1
local r = 1
for id, ref in pairs(layers) do
if ref.in_deg == 0 then
table.insert(queue, ref)
nerv.info("adding source layer: %s", id)
r = r + 1
end
end
if l == r then
nerv.error("loop detected")
end
while l < r do
local cur = queue[l]
cur.visited = true
l = l + 1
for _, nl in pairs(cur.next_layers) do
nl.in_deg = nl.in_deg - 1
if nl.in_deg == 0 then
table.insert(queue, nl)
r = r + 1
end
end
end
for i = 1, #queue do
nerv.info("enqueued layer: %s", queue[i].layer.id)
end
for id, ref in pairs(layers) do
-- check wether the graph is connected
if ref.visited == false then
nerv.warning("layer %s is ignored", id)
end
end
self.layers = layers
self.inputs = inputs
self.outputs = outputs
self.dim_in = dim_in
self.dim_out = dim_out
self.parsed_conn = parsed_conn
self.queue =