.

optim_nn_core.py

@@ -874,3 +874,39 @@ class SGDR(Learner):
             if self.restart_callback is not None:
                 self.restart_callback(restart)
         return True
+
+class TriangularCLR(Learner):
+    # note: i haven't actually read (nor seen) the paper(s) on CLR,
+    # but this case (triangular) should be pretty difficult to get wrong.
+
+    per_batch = True
+
+    def __init__(self, optim, epochs=400, upper_rate=None, lower_rate=0,
+                 frequency=100, callback=None):
+        # NOTE: start_rate is treated as upper_rate
+        self.frequency = int(frequency)
+        assert self.frequency > 0
+        self.callback = callback
+        self.lower_rate = _f(lower_rate)
+        super().__init__(optim, epochs, upper_rate)
+
+    def _t(self, epoch):
+        # NOTE: this could probably be simplified
+        offset = self.frequency / 2
+        return np.abs(((epoch + offset) % self.frequency) - offset) / offset
+
+    def rate_at(self, epoch):
+        # NOTE: start_rate is treated as upper_rate
+        return self._t(epoch) * (self.start_rate - self.lower_rate) + self.lower_rate
+
+    def next(self):
+        if not super().next():
+            return False
+        if self.epoch > 1 and self.epoch % self.frequency == 0:
+            if self.callback is not None:
+                self.callback(self.epoch // self.frequency)
+        return True
+
+class SineCLR(TriangularCLR):
+    def _t(self, epoch):
+        return np.sin(_pi * _inv2 * super()._t(epoch))

optim_nn_mnist.py

@@ -5,15 +5,15 @@ from optim_nn_core import _f
 
 #np.random.seed(42069)
 
-#           train loss:   4.194040e-02
-#       train accuracy:    99.46%
-#           valid loss:   1.998158e-01
-#       valid accuracy:    97.26%
+#           train loss:   7.048363e-03
+#       train accuracy:    99.96%
+#           valid loss:   3.062232e-01
+#       valid accuracy:    97.22%
 # TODO: add dropout or something to lessen overfitting
 
-lr = 0.01
-epochs = 24
-starts = 2
+lr = 0.0032
+epochs = 125
+starts = 5
 restart_decay = 0.5
 bs = 100
 
@@ -64,9 +64,15 @@ y = y.feed(Softmax())
 model = Model(x, y, unsafe=True)
 
 optim = Adam()
-learner = SGDR(optim, epochs=epochs//starts, rate=lr,
-               restarts=starts - 1, restart_decay=restart_decay,
-               expando=lambda i:0)
+if 0:
+    learner = SGDR(optim, epochs=epochs//starts, rate=lr,
+                   restarts=starts-1, restart_decay=restart_decay,
+                   expando=lambda i:0)
+else:
+#   learner = TriangularCLR(optim, epochs=epochs, lower_rate=0, upper_rate=lr,
+#                           frequency=epochs//starts)
+    learner = SineCLR(optim, epochs=epochs, lower_rate=0, upper_rate=lr,
+                      frequency=epochs//starts)
 
 loss = CategoricalCrossentropy()
 mloss = Accuracy()
@@ -89,9 +95,10 @@ def measure_error(quiet=False):
             log(name + " accuracy", "{:6.2f}%".format(mloss * 100))
         return loss, mloss
 
-    loss, mloss = print_error("train", inputs, outputs)
-    train_losses.append(loss)
-    train_mlosses.append(mloss)
+    if not quiet:
+        loss, mloss = print_error("train", inputs, outputs)
+        train_losses.append(loss)
+        train_mlosses.append(mloss)
     loss, mloss = print_error("valid", valid_inputs, valid_outputs)
     valid_losses.append(loss)
     valid_mlosses.append(mloss)