added ELU unit incl documentation

1 files changed, 26 insertions, 3 deletions

diff --git a/ELU.lua b/ELU.lua
index a6eb271..f3f7dd1 100644
--- a/ELU.lua
+++ b/ELU.lua
@@ -1,5 +1,28 @@
-local ReLU, Parent = torch.class('nn.ReLU', 'nn.Threshold')
+local ELU, parent = torch.class('nn.ELU', 'nn.Module')
 
-function ReLU:__init(p)
-   Parent.__init(self,0,0,p)
+
+--[[
+   Djork-Arné Clevert, Thomas Unterthiner, Sepp Hochreiter
+   Fast and Accurate Deep Network Learning by Exponential Linear Units (ELUs) 
+   http://arxiv.org/pdf/1511.07289.pdf
+--]]
+
+function ELU:__init(alpha)
+   parent.__init(self)
+   self.alpha = alpha or 1
+   assert(type(self.alpha) == 'number')
+end
+
+function ELU:updateOutput(input)
+   input.nn.ELU_updateOutput(self, input)
+   return self.output
+end
+
+function ELU:updateGradInput(input, gradOutput)
+   input.nn.ELU_updateGradInput(self, input, gradOutput)
+   return self.gradInput
+end
+
+function ELU:__tostring__()
+  return string.format('%s (alpha:%f)', torch.type(self), self.alpha)
 end