1 files changed, 41 insertions, 0 deletions
diff --git a/nerv/layer/duplicate.lua b/nerv/layer/duplicate.lua
new file mode 100644
index 0000000..137472b
--- /dev/null
+++ b/nerv/layer/duplicate.lua
@@ -0,0 +1,41 @@
+local DuplicateLayer = nerv.class('nerv.DuplicateLayer', 'nerv.Layer')
+
+function DuplicateLayer:__init(id, global_conf, layer_conf)
+    nerv.Layer.__init(self, id, global_conf, layer_conf)
+    self:check_dim_len(1, -1)
+    if #self.dim_out < 1 then
+        nerv.error('no output specified')
+    end
+    for i = 1, #self.dim_out do
+        if self.dim_out[i] ~= self.dim_in[1] then
+            nerv.error('mismatching dimensions of outputs')
+        end
+    end
+end
+
+function DuplicateLayer:init()
+end
+
+function DuplicateLayer:batch_resize()
+end
+
+function DuplicateLayer:propagate(input, output)
+    for i = 1, #self.dim_out do
+        output[i]:copy_from(input[1])
+        -- FIXME: use reference copy to speed up
+    end
+end
+
+function DuplicateLayer:back_propagate(bp_err, next_bp_err)
+    next_bp_err[1]:copy_from(bp_err[1])
+    for i = 2, #self.dim_out do
+        next_bp_err[1]:add(next_bp_err[1], bp_err[i], 1.0, 1.0)
+    end
+end
+
+function DuplicateLayer:update()
+end
+
+function DuplicateLayer:get_params()
+    return nerv.ParamRepo({}, self.loc_type)
+end