1 files changed, 68 insertions, 0 deletions
diff --git a/nerv/layer/softmax_ce.lua b/nerv/layer/softmax_ce.lua
new file mode 100644
index 0000000..daf891e
--- /dev/null
+++ b/nerv/layer/softmax_ce.lua
@@ -0,0 +1,68 @@
+local SoftmaxCELayer = nerv.class("nerv.SoftmaxCELayer", "nerv.Layer")
+
+function SoftmaxCELayer:__init(id, global_conf, layer_conf)
+    self.id = id
+    self.gconf = global_conf
+    self.dim_in = layer_conf.dim_in
+    self.dim_out = layer_conf.dim_out
+    self.compressed = layer_conf.compressed
+    if self.compressed == nil then
+        self.compressed = false
+    end
+    self:check_dim_len(2, -1) -- two inputs: nn output and label
+end
+
+function SoftmaxCELayer:init(batch_size)
+    if not self.compressed and (self.dim_in[1] ~= self.dim_in[2]) then
+        nerv.error("mismatching dimensions of previous network output and labels")
+    end
+    self.total_ce = 0.0
+    self.total_correct = 0
+    self.total_frames = 0
+    self.softmax = self.gconf.cumat_type(batch_size, self.dim_in[1])
+    self.ce = self.softmax:create()
+end
+
+function SoftmaxCELayer:update(bp_err, input, output)
+    -- no params, therefore do nothing
+end
+
+function SoftmaxCELayer:propagate(input, output)
+    local softmax = self.softmax
+    local ce = self.ce
+    local classified = softmax:softmax(input[1])
+    local label = input[2]
+    ce:log_elem(softmax)
+    if self.compressed then
+        label = label:decompress(input[1]:ncol())
+    end
+    ce:mul_elem(ce, label)
+    ce = ce:rowsum()
+    if output[1] ~= nil then
+        output[1]:copy_fromd(ce)
+    end
+    -- add total ce
+    self.total_ce = self.total_ce - ce:colsum()[0]
+    self.total_frames = self.total_frames + softmax:nrow()
+    -- TODO: add colsame for uncompressed label
+    if self.compressed then
+        self.total_correct = self.total_correct + classified:colsame(input[2])[0]
+    end
+end
+
+function SoftmaxCELayer:back_propagate(bp_err, next_bp_err, input, output)
+    -- softmax output - label
+    local label = input[2]
+    if self.compressed then
+        label = label:decompress(input[1]:ncol())
+    end
+    local nbe = next_bp_err[1]
+    nbe:add(self.softmax, label, 1.0, -1.0)
+    if bp_err[1] ~= nil then
+        nbe:scale_rows_by_col(bp_err[1])
+    end
+end
+
+function SoftmaxCELayer:get_params()
+    return nerv.ParamRepo({})
+end