.

optim_nn.py

@@ -347,8 +347,17 @@ class Dense(Layer):
         super().__init__()
         self.dim = ni(dim)
         self.output_shape = (dim,)
-        self.size = None
         self.weight_init = init
+        self.size = None
+
+    def make_shape(self, shape):
+        super().make_shape(shape)
+        if len(shape) != 1:
+            return False
+        self.nW = self.dim * shape[0]
+        self.nb = self.dim
+        self.size = self.nW + self.nb
+        return shape
 
     def init(self, W, dW):
         ins, outs = self.input_shape[0], self.output_shape[0]
@@ -363,15 +372,6 @@ class Dense(Layer):
         self.coeffs.flat = self.weight_init(self.nW, ins, outs)
         self.biases.flat = 0
 
-    def make_shape(self, shape):
-        super().make_shape(shape)
-        if len(shape) != 1:
-            return False
-        self.nW = self.dim * shape[0]
-        self.nb = self.dim
-        self.size = self.nW + self.nb
-        return shape
-
     def F(self, X):
         self.X = X
         Y = X.dot(self.coeffs) \
@@ -381,7 +381,53 @@ class Dense(Layer):
     def dF(self, dY):
         dX = dY.dot(self.coeffs.T)
         self.dcoeffs[:] = self.X.T.dot(dY)
-        self.dbiases[:] = np.sum(dY, axis=0, keepdims=True)
+        self.dbiases[:] = dY.sum(0, keepdims=True)
+        return dX
+
+class DenseOneLess(Dense):
+    def init(self, W, dW):
+        super().init(W, dW)
+        ins, outs = self.input_shape[0], self.output_shape[0]
+        assert ins == outs, (ins, outs)
+
+    def F(self, X):
+        np.fill_diagonal(self.coeffs, 0)
+        self.X = X
+        Y = X.dot(self.coeffs) \
+          + self.biases
+        return Y
+
+    def dF(self, dY):
+        dX = dY.dot(self.coeffs.T)
+        self.dcoeffs[:] = self.X.T.dot(dY)
+        self.dbiases[:] = dY.sum(0, keepdims=True)
+        np.fill_diagonal(self.dcoeffs, 0)
+        return dX
+
+class LayerNorm(Layer): # TODO: inherit Affine instead?
+    def __init__(self, eps=1e-3, axis=-1):
+        super().__init__()
+        self.eps = nf(eps)
+        self.axis = int(axis)
+
+    def F(self, X):
+        self.center = X - np.mean(X, axis=self.axis, keepdims=True)
+        #self.var = np.var(X, axis=self.axis, keepdims=True) + self.eps
+        self.var = np.mean(np.square(self.center), axis=self.axis, keepdims=True) + self.eps
+        self.std = np.sqrt(self.var) + self.eps
+        Y = self.center / self.std
+        return Y
+
+    def dF(self, dY):
+        length = self.input_shape[self.axis]
+
+        dstd     = dY * (-self.center / self.var)
+        dvar     = dstd * (0.5 / self.std)
+        dcenter2 = dvar * (1 / length)
+        dcenter  = dY * (1 / self.std)
+        dcenter += dcenter2 * (2 * self.center)
+        dX       = dcenter - dcenter / length
+
         return dX
 
 # Model
@@ -527,6 +573,8 @@ class Ritual:
             self.update(model.dW, model.W)
 
             batch_loss = self.measure(residual)
+            if np.isnan(batch_loss):
+                raise Exception("nan")
             cumsum_loss += batch_loss
             if return_losses:
                 losses.append(batch_loss)
@@ -542,6 +590,9 @@ def multiresnet(x, width, depth, block=2, multi=1,
     y = x
     last_size = x.output_shape[0]
 
+    FC = lambda size: Dense(size, init)
+    #FC = lambda size: DenseOneLess(size, init)
+
     for d in range(depth):
         size = width
 
@@ -558,7 +609,7 @@ def multiresnet(x, width, depth, block=2, multi=1,
                 for i in range(block):
                     if i > 0:
                         z = z.feed(activation())
-                    z = z.feed(Dense(size, init))
+                    z = z.feed(FC(size))
                 z.feed(merger)
             y = merger
         elif style == 'onelesssum':
@@ -575,7 +626,7 @@ def multiresnet(x, width, depth, block=2, multi=1,
                 for i in range(block):
                     if i > 0:
                         z = z.feed(activation())
-                    z = z.feed(Dense(size, init))
+                    z = z.feed(FC(size))
                 if needs_sum:
                     z.feed(merger)
             if needs_sum:
@@ -630,7 +681,7 @@ def run(program, args=[]):
         # misc
         batch_size = 64,
         init = 'he_normal',
-        loss = SomethingElse(4/3),
+        loss = SomethingElse(),
         mloss = 'mse',
         restart_optim = True, # restarts also reset internal state of optimizer
         unsafe = True, # aka gotta go fast mode
@@ -666,14 +717,22 @@ def run(program, args=[]):
     y = multiresnet(y,
                     config.res_width, config.res_depth,
                     config.res_block, config.res_multi,
-                    activation=activation, init=init)
+                    activation=activation, init=init,
+                    style=config.parallel_style)
     if y.output_shape[0] != output_samples:
         y = y.feed(Dense(output_samples, init))
 
     model = Model(x, y, unsafe=config.unsafe)
 
+    if 0:
         node_names = ' '.join([str(node) for node in model.ordered_nodes])
         log('{} nodes'.format(len(model.ordered_nodes)), node_names)
+    else:
+        for node in model.ordered_nodes:
+            children = [str(n) for n in node.children]
+            if len(children) > 0:
+                sep = '->'
+                print(str(node)+sep+('\n'+str(node)+sep).join(children))
     log('parameters', model.param_count)
 
     training = config.epochs > 0 and config.restarts >= 0