add CombinerLayer to support branches in NN; add MSELayer

1 files changed, 52 insertions, 0 deletions

diff --git a/layer/mse.lua b/layer/mse.lua
new file mode 100644
index 0000000..da5b24d
--- /dev/null
+++ b/layer/mse.lua
@@ -0,0 +1,52 @@
+local MSELayer = nerv.class("nerv.MSELayer", "nerv.Layer")
+
+function MSELayer:__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:check_dim_len(2, -1)
+end
+
+function MSELayer:init()
+    if self.dim_in[1] ~= self.dim_in[2] then
+        nerv.error("mismatching dimensions of previous network output and labels")
+    end
+    self.total_mse = 0.0
+    self.total_frames = 0
+end
+
+function MSELayer:update(bp_err, input, output)
+    -- no params, therefore do nothing
+end
+
+function MSELayer:propagate(input, output)
+    local mse = input[1]:create()
+    mse:add(input[1], input[2], 1.0, -1.0)
+    self.diff = mse:create()
+    self.diff:copy_fromd(mse)
+    mse:mul_elem(mse, mse)
+    mse = mse:rowsum(mse)
+    local scale = nerv.CuMatrixFloat(mse:nrow(), 1)
+    scale:fill(1 / input[1]:ncol())
+    mse:scale_rows_by_col(scale)
+    if output[1] ~= nil then
+        output[1]:copy_fromd(mse)
+    end
+    self.total_mse = self.total_mse + mse:colsum()[0]
+    self.total_frames = self.total_frames + mse:nrow()
+end
+
+-- NOTE: must call propagate before back_propagate
+function MSELayer:back_propagate(next_bp_err, bp_err, input, output)
+    local nbe = next_bp_err[1]
+    nbe:copy_fromd(self.diff)
+    self.diff = nil
+    if bp_err[1] ~= nil then
+        nbe:scale_rows_by_col(bp_err[1])
+    end
+end
+
+function MSELayer:get_params()
+    return {}
+end