add CyclicalCosineDecay (#1599)

ppocr/optimizer/learning_rate.py

@@ -18,6 +18,7 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 from paddle.optimizer import lr
+from .lr_scheduler import CyclicalCosineDecay
 
 
 class Linear(object):
@@ -46,7 +47,7 @@ class Linear(object):
         self.end_lr = end_lr
         self.power = power
         self.last_epoch = last_epoch
-        self.warmup_epoch = warmup_epoch * step_each_epoch
+        self.warmup_epoch = round(warmup_epoch * step_each_epoch)
 
     def __call__(self):
         learning_rate = lr.PolynomialDecay(
@@ -87,7 +88,7 @@ class Cosine(object):
         self.learning_rate = learning_rate
         self.T_max = step_each_epoch * epochs
         self.last_epoch = last_epoch
-        self.warmup_epoch = warmup_epoch * step_each_epoch
+        self.warmup_epoch = round(warmup_epoch * step_each_epoch)
 
     def __call__(self):
         learning_rate = lr.CosineAnnealingDecay(
@@ -129,7 +130,7 @@ class Step(object):
         self.learning_rate = learning_rate
         self.gamma = gamma
         self.last_epoch = last_epoch
-        self.warmup_epoch = warmup_epoch * step_each_epoch
+        self.warmup_epoch = round(warmup_epoch * step_each_epoch)
 
     def __call__(self):
         learning_rate = lr.StepDecay(
@@ -168,7 +169,7 @@ class Piecewise(object):
         self.boundaries = [step_each_epoch * e for e in decay_epochs]
         self.values = values
         self.last_epoch = last_epoch
-        self.warmup_epoch = warmup_epoch * step_each_epoch
+        self.warmup_epoch = round(warmup_epoch * step_each_epoch)
 
     def __call__(self):
         learning_rate = lr.PiecewiseDecay(
@@ -183,3 +184,45 @@ class Piecewise(object):
                 end_lr=self.values[0],
                 last_epoch=self.last_epoch)
         return learning_rate
+
+
+class CyclicalCosine(object):
+    """
+    Cyclical cosine learning rate decay
+    Args:
+        learning_rate(float): initial learning rate
+        step_each_epoch(int): steps each epoch
+        epochs(int): total training epochs
+        cycle(int): period of the cosine learning rate
+        last_epoch (int, optional):  The index of last epoch. Can be set to restart training. Default: -1, means initial learning rate.
+    """
+
+    def __init__(self,
+                 learning_rate,
+                 step_each_epoch,
+                 epochs,
+                 cycle,
+                 warmup_epoch=0,
+                 last_epoch=-1,
+                 **kwargs):
+        super(CyclicalCosine, self).__init__()
+        self.learning_rate = learning_rate
+        self.T_max = step_each_epoch * epochs
+        self.last_epoch = last_epoch
+        self.warmup_epoch = round(warmup_epoch * step_each_epoch)
+        self.cycle = round(cycle * step_each_epoch)
+
+    def __call__(self):
+        learning_rate = CyclicalCosineDecay(
+            learning_rate=self.learning_rate,
+            T_max=self.T_max,
+            cycle=self.cycle,
+            last_epoch=self.last_epoch)
+        if self.warmup_epoch > 0:
+            learning_rate = lr.LinearWarmup(
+                learning_rate=learning_rate,
+                warmup_steps=self.warmup_epoch,
+                start_lr=0.0,
+                end_lr=self.learning_rate,
+                last_epoch=self.last_epoch)
+        return learning_rate

ppocr/optimizer/lr_scheduler.py

+# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import math
+from paddle.optimizer.lr import LRScheduler
+
+
+class CyclicalCosineDecay(LRScheduler):
+    def __init__(self,
+                 learning_rate,
+                 T_max,
+                 cycle=1,
+                 last_epoch=-1,
+                 eta_min=0.0,
+                 verbose=False):
+        """
+        Cyclical cosine learning rate decay
+        A learning rate which can be referred in https://arxiv.org/pdf/2012.12645.pdf
+        Args:
+            learning rate(float): learning rate
+            T_max(int): maximum epoch num
+            cycle(int): period of the cosine decay
+            last_epoch (int, optional):  The index of last epoch. Can be set to restart training. Default: -1, means initial learning rate.
+            eta_min(float): minimum learning rate during training
+            verbose(bool): whether to print learning rate for each epoch
+        """
+        super(CyclicalCosineDecay, self).__init__(learning_rate, last_epoch,
+                                                  verbose)
+        self.cycle = cycle
+        self.eta_min = eta_min
+
+    def get_lr(self):
+        if self.last_epoch == 0:
+            return self.base_lr
+        reletive_epoch = self.last_epoch % self.cycle
+        lr = self.eta_min + 0.5 * (self.base_lr - self.eta_min) * \
+                (1 + math.cos(math.pi * reletive_epoch / self.cycle))
+        return lr

tools/program.py

@@ -179,9 +179,9 @@ def train(config,
     if 'start_epoch' in best_model_dict:
         start_epoch = best_model_dict['start_epoch']
     else:
-        start_epoch = 0
+        start_epoch = 1
 
-    for epoch in range(start_epoch, epoch_num):
+    for epoch in range(start_epoch, epoch_num + 1):
         if epoch > 0:
             train_dataloader = build_dataloader(config, 'Train', device, logger)
         train_batch_cost = 0.0