1 files changed, 31 insertions, 0 deletions
diff --git a/nerv/layer/sigmoid.lua b/nerv/layer/sigmoid.lua
new file mode 100644
index 0000000..dfd09eb
--- /dev/null
+++ b/nerv/layer/sigmoid.lua
@@ -0,0 +1,31 @@
+local SigmoidLayer = nerv.class("nerv.SigmoidLayer", "nerv.Layer")
+
+function SigmoidLayer:__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:check_dim_len(1, 1)
+end
+
+function SigmoidLayer:init()
+    if self.dim_in[1] ~= self.dim_out[1] then
+        nerv.error("mismatching dimensions of input and output")
+    end
+end
+
+function SigmoidLayer:update(bp_err, input, output)
+    -- no params, therefore do nothing
+end
+
+function SigmoidLayer:propagate(input, output)
+    output[1]:sigmoid(input[1])
+end
+
+function SigmoidLayer:back_propagate(bp_err, next_bp_err, input, output)
+    next_bp_err[1]:sigmoid_grad(bp_err[1], output[1])
+end
+
+function SigmoidLayer:get_params()
+    return nerv.ParamRepo({})
+end