remove remnants of backwards pass

nn.lua

@@ -367,6 +367,7 @@ end
 
 function Layer:reset_cache(bs)
     self.bs = bs
+    self.cache = cache(bs, self.shape_out)
 end
 
 function Layer:_propagate(edges, deterministic)
@@ -417,12 +418,6 @@ function Merge:make_shape(parent)
     self.shape_out = {self.size}
 end
 
-function Merge:reset_cache(bs)
-    self.bs = bs
-
-    self.cache  = cache(bs, self.shape_out)
-end
-
 function Merge:_propagate(edges, deterministic)
     assert(#edges == self.shape_in)
     local bs = edges[1].shape[1]
@@ -445,13 +440,6 @@ function Relu:init()
     Layer.init(self, "Relu")
 end
 
-function Relu:reset_cache(bs)
-    self.bs = bs
-
-    self.cache  = cache(bs, self.shape_out)
-    self.dcache = cache(bs, self.shape_in)
-end
-
 function Relu:forward(X)
     local bs = checkshape(X, self.shape_in)
     if bs ~= self.bs then self:reset_cache(bs) end
@@ -467,27 +455,14 @@ function Gelu:init()
     Layer.init(self, "Gelu")
 end
 
-function Gelu:reset_cache(bs)
-    self.bs = bs
-
-    self.cache     = cache(bs, self.shape_out)
-    self.cache_a   = cache(bs, self.shape_out)
-    self.cache_sig = cache(bs, self.shape_out)
-    self.dcache    = cache(bs, self.shape_in)
-end
-
 function Gelu:forward(X)
     local bs = checkshape(X, self.shape_in)
     if bs ~= self.bs then self:reset_cache(bs) end
     local Y = self.cache
-    local a = self.cache_a
-    local sig = self.cache_sig
 
     -- NOTE: approximate form of GELU exploiting similarities to sigmoid curve.
     for i = 1, #X do
-        a[i] = 1.704 * X[i]
+        Y[i] = X[i] / (1 + exp(-1.704 * X[i]))
-        sig[i] = 1 / (1 + exp(-a[i]))
-        Y[i] = X[i] * sig[i]
     end
 
     checkshape(Y, self.shape_out)
@@ -498,13 +473,6 @@ function Cos:init()
     Layer.init(self, "Cos")
 end
 
-function Cos:reset_cache(bs)
-    self.bs = bs
-
-    self.cache  = cache(bs, self.shape_out)
-    self.dcache = cache(bs, self.shape_in)
-end
-
 function Cos:forward(X)
     local bs = checkshape(X, self.shape_in)
     if bs ~= self.bs then self:reset_cache(bs) end
@@ -520,13 +488,6 @@ function Tanh:init()
     Layer.init(self, "Tanh")
 end
 
-function Tanh:reset_cache(bs)
-    self.bs = bs
-
-    self.cache  = cache(bs, self.shape_out)
-    self.dcache = cache(bs, self.shape_in)
-end
-
 function Tanh:forward(X)
     local bs = checkshape(X, self.shape_in)
     if bs ~= self.bs then self:reset_cache(bs) end
@@ -553,20 +514,11 @@ function Dense:make_shape(parent)
     self.biases.shape = {1, self.dim}
 end
 
-function Dense:reset_cache(bs)
-    self.bs = bs
-
-    self.cache   = cache(bs, self.shape_out)
-    self.cache_x = cache(bs, self.shape_in)
-    self.dcache  = cache(bs, self.shape_in)
-end
-
 function Dense:forward(X)
     local bs = checkshape(X, self.shape_in)
     if self.bs ~= bs then self:reset_cache(bs) end
     local Y = self.cache
 
-    --dot_1aab(X, self.coeffs, Y)
     dot(X, self.coeffs, 2, 1, Y)
 
     for i = 1, self.dim do
@@ -581,12 +533,6 @@ function Softmax:init()
     Layer.init(self, "Softmax")
 end
 
-function Softmax:reset_cache(bs)
-    self.bs = bs
-
-    self.cache = cache(bs, self.shape_out)
-end
-
 function Softmax:forward(X)
     local bs = checkshape(X, self.shape_in)
     if self.bs ~= bs then self:reset_cache(bs) end
@@ -624,13 +570,6 @@ function Embed:make_shape(parent)
     self.shape_out = {parent.shape_out[1] * self.dim}
 end
 
-function Embed:reset_cache(bs)
-    self.bs = bs
-
-    self.cache   = cache(bs, self.shape_out)
-    self.cache_x = cache(bs, self.shape_in)
-end
-
 function Embed:forward(X)
     local bs = checkshape(X, self.shape_in)
     if self.bs ~= bs then self:reset_cache(bs) end
@@ -656,11 +595,6 @@ function LayerNorm:init(eps)
     self.eps = eps
 end
 
-function LayerNorm:reset_cache(bs)
-    self.bs = bs
-    self.cache = cache(bs, self.shape_out)
-end
-
 function LayerNorm:forward(X)
     local bs = checkshape(X, self.shape_in)
     if self.bs ~= bs then self:reset_cache(bs) end
@@ -727,10 +661,6 @@ function Model:forward(inputs)
     return outputs
 end
 
-function Model:cleargrad()
-    error("TODO") -- TODO
-end
-
 function Model:print()
     print("digraph G {")
     for _, parent in ipairs(self.nodes) do