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Diffstat (limited to 'tensorflow/contrib/training/python/training/sgdr_learning_rate_decay_test.py')
-rw-r--r-- | tensorflow/contrib/training/python/training/sgdr_learning_rate_decay_test.py | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/tensorflow/contrib/training/python/training/sgdr_learning_rate_decay_test.py b/tensorflow/contrib/training/python/training/sgdr_learning_rate_decay_test.py new file mode 100644 index 0000000000..4a46e9a49e --- /dev/null +++ b/tensorflow/contrib/training/python/training/sgdr_learning_rate_decay_test.py @@ -0,0 +1,145 @@ +# Copyright 2015 The TensorFlow Authors. All Rights Reserved. +# +# 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. +# ============================================================================== + +"""Functional test for sgdr learning rate decay.""" +from __future__ import absolute_import +from __future__ import division +from __future__ import print_function + +import math + +from sgdr_learning_rate_decay import sgdr_decay +from tensorflow.python.platform import googletest +from tensorflow.python.framework import test_util +from tensorflow.python.framework import dtypes +from tensorflow import placeholder + + +class SGDRDecayTest(test_util.TensorFlowTestCase): + """Unit tests for SGDR learning rate decay.""" + + def get_original_values(self, lr, t_e, mult_factor, iter_per_epoch, epochs): + """Get an array with learning rate values from the consecutive steps using + the original implementation + (https://github.com/loshchil/SGDR/blob/master/SGDR_WRNs.py).""" + t0 = math.pi / 2.0 + tt = 0 + te_next = t_e + + lr_values = [] + sh_lr = lr + for epoch in range(epochs): + for _ in range(iter_per_epoch): + # In the original approach training function is executed here + lr_values.append(sh_lr) + dt = 2.0 * math.pi / float(2.0 * t_e) + tt = tt + float(dt) / iter_per_epoch + if tt >= math.pi: + tt = tt - math.pi + cur_t = t0 + tt + new_lr = lr * (1.0 + math.sin(cur_t)) / 2.0 # lr_min = 0, lr_max = lr + sh_lr = new_lr + if (epoch + 1) == te_next: # time to restart + sh_lr = lr + tt = 0 # by setting to 0 we set lr to lr_max, see above + t_e = t_e * mult_factor # change the period of restarts + te_next = te_next + t_e # note the next restart's epoch + + return lr_values + + def get_sgdr_values(self, lr, initial_period_steps, t_mul, iters): + """Get an array with learning rate values from the consecutive steps + using current tensorflow implementation.""" + with self.test_session(): + step = placeholder(dtypes.int32) + + decay = sgdr_decay(lr, step, initial_period_steps, t_mul) + lr_values = [] + for i in range(iters): + lr_values.append(decay.eval(feed_dict={step: i})) + + return lr_values + + def testCompareToOriginal(self): + """Compare values generated by tensorflow implementation to the values + generated by the original implementation + (https://github.com/loshchil/SGDR/blob/master/SGDR_WRNs.py).""" + with self.test_session(): + lr = 10.0 + init_steps = 2 + t_mul = 3 + iters = 10 + epochs = 50 + + org_lr = self.get_original_values(lr, init_steps, t_mul, iters, epochs) + sgdr_lr = self.get_sgdr_values(lr, init_steps*iters, t_mul, iters*epochs) + + for org, sgdr in zip(org_lr, sgdr_lr): + self.assertAllClose(org, sgdr) + + def testMDecay(self): + """Test m_mul argument. Check values for learning rate at the beginning + of the first, second, third and fourth period. """ + with self.test_session(): + step = placeholder(dtypes.int32) + + lr = 0.1 + t_e = 10 + t_mul = 3 + m_mul = 0.9 + + decay = sgdr_decay(lr, step, t_e, t_mul, m_mul) + + test_step = 0 + self.assertAllClose(decay.eval(feed_dict={step: test_step}), + lr) + + test_step = t_e + self.assertAllClose(decay.eval(feed_dict={step: test_step}), + lr * m_mul) + + test_step = t_e + t_e*t_mul + self.assertAllClose(decay.eval(feed_dict={step: test_step}), + lr * m_mul**2) + + test_step = t_e + t_e*t_mul + t_e * (t_mul**2) + self.assertAllClose(decay.eval(feed_dict={step: test_step}), + lr * (m_mul**3)) + + def testCos(self): + """Check learning rate values at the beginning, in the middle + and at the end of the period.""" + with self.test_session(): + step = placeholder(dtypes.int32) + lr = 0.2 + t_e = 1000 + t_mul = 1 + + decay = sgdr_decay(lr, step, t_e, t_mul) + + test_step = 0 + self.assertAllClose(decay.eval(feed_dict={step: test_step}), lr) + + test_step = t_e//2 + self.assertAllClose(decay.eval(feed_dict={step: test_step}), lr/2) + + test_step = t_e + self.assertAllClose(decay.eval(feed_dict={step: test_step}), lr) + + test_step = t_e*3//2 + self.assertAllClose(decay.eval(feed_dict={step: test_step}), lr/2) + +if __name__ == "__main__": + googletest.main() |