Exponential Parameter Scheduler

classy_vision/optim/param_scheduler/__init__.py

@@ -75,6 +75,7 @@ def register_param_scheduler_cls(cls):
 from .fvcore_schedulers import (
     ConstantParamScheduler,
     CosineParamScheduler,
+    ExponentialParamScheduler,
     LinearParamScheduler,
     MultiStepParamScheduler,
     PolynomialDecayParamScheduler,
@@ -88,6 +89,7 @@ def register_param_scheduler_cls(cls):
     "CompositeParamScheduler",
     "ConstantParamScheduler",
     "CosineParamScheduler",
+    "ExponentialParamScheduler",
     "LinearParamScheduler",
     "MultiStepParamScheduler",
     "PolynomialDecayParamScheduler",

classy_vision/optim/param_scheduler/fvcore_schedulers.py

@@ -70,6 +70,12 @@ def from_config(cls, config: Dict[str, Any]) -> param_scheduler.ParamScheduler:
     default_update_interval=UpdateInterval.STEP,
 )
 
+ExponentialParamScheduler = _create_classy_scheduler_class(
+    param_scheduler.ExponentialParamScheduler,
+    "exponential",
+    default_update_interval=UpdateInterval.STEP,
+)
+
 LinearParamScheduler = _create_classy_scheduler_class(
     param_scheduler.LinearParamScheduler,
     "linear",

test/optim_param_scheduler_exponential_test.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import copy
+import unittest
+
+from classy_vision.optim.param_scheduler import (
+    build_param_scheduler,
+    ExponentialParamScheduler,
+)
+
+
+class TestExponentialScheduler(unittest.TestCase):
+    _num_epochs = 10
+
+    def _get_valid_config(self):
+        return {"name": "exponential", "start_value": 2.0, "decay": 0.1}
+
+    def _get_valid_intermediate_values(self):
+        return [1.5887, 1.2619, 1.0024, 0.7962, 0.6325, 0.5024, 0.3991, 0.3170, 0.2518]
+
+    def test_invalid_config(self):
+        config = self._get_valid_config()
+
+        bad_config = copy.deepcopy(config)
+        # Invalid Base lr
+        del bad_config["start_value"]
+        with self.assertRaises((AssertionError, TypeError)):
+            ExponentialParamScheduler.from_config(bad_config)
+
+        # Invalid decay
+        bad_config["start_value"] = config["start_value"]
+        del bad_config["decay"]
+        with self.assertRaises((AssertionError, TypeError)):
+            ExponentialParamScheduler.from_config(bad_config)
+
+    def test_scheduler(self):
+        config = self._get_valid_config()
+
+        scheduler = ExponentialParamScheduler.from_config(config)
+        schedule = [
+            round(scheduler(epoch_num / self._num_epochs), 4)
+            for epoch_num in range(self._num_epochs)
+        ]
+        expected_schedule = [
+            config["start_value"]
+        ] + self._get_valid_intermediate_values()
+
+        self.assertEqual(schedule, expected_schedule)
+
+    def test_build_exponential_scheduler(self):
+        config = self._get_valid_config()
+        scheduler = build_param_scheduler(config)
+        self.assertTrue(isinstance(scheduler, ExponentialParamScheduler))