zhreshold commented on a change in pull request #8005: add warmup lr_scheduler
URL: https://github.com/apache/incubator-mxnet/pull/8005#discussion_r141697319
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File path: tests/python/unittest/test_lr_scheduler.py
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@@ -0,0 +1,57 @@
+import logging
+import mxnet as mx
+import mxnet.optimizer as opt
+
+def test_lr_sceduler(lr, steps, lr_factor, warmup_step, warmup_lr):
+ logging.basicConfig(level=logging.DEBUG)
+
+ lr_scheduler = None
+ if warmup_step > 0 and warmup_lr > lr:
+ lr_scheduler = mx.lr_scheduler.MultiFactorScheduler(step=steps,
factor=lr_factor,
+ warmup_step = warmup_step, begin_lr=lr, stop_lr=warmup_lr)
+ else:
+ lr_scheduler = mx.lr_scheduler.MultiFactorScheduler(step=steps,
factor=lr_factor)
+
+ optimizer_params = {
+ 'learning_rate': lr,
+ 'lr_scheduler': lr_scheduler}
+
+ optimizer = opt.create('sgd', **optimizer_params)
+ updater = opt.get_updater(optimizer)
+
+ x = [[[[i*10+j for j in range(10)] for i in range(10)]]]
+ x = mx.nd.array(x, dtype='float32')
+ y = mx.nd.ones(shape = x.shape, dtype='float32')
+
+ res_lr = []
+ for i in range(1,steps[-1] + 5):
+ updater(0, y, x)
+ cur_lr = optimizer._get_lr(0)
+ res_lr.append(cur_lr)
+ logging.info("step %d lr = %f", i, cur_lr)
+
+ if warmup_step > 1:
+ assert mx.test_utils.almost_equal(res_lr[warmup_step], warmup_lr,
1e-10)
+ lr = warmup_lr
+ for i in range(len(steps)):
+ assert mx.test_utils.almost_equal(res_lr[steps[i]], lr *
pow(lr_factor, i + 1), 1e-10)
+
+if __name__ == "__main__":
+ #Legal input
+ test_lr_sceduler(lr = 0.2, steps = [8,12], lr_factor = 0.1, warmup_step =
0, warmup_lr = 0.1)
+ test_lr_sceduler(lr = 0.02, steps = [8,12], lr_factor = 0.1, warmup_step =
1, warmup_lr = 0.1)
+ test_lr_sceduler(lr = 0.02, steps = [8,12], lr_factor = 0.3, warmup_step =
5, warmup_lr = 0.1)
+ test_lr_sceduler(lr = 0.002, steps = [8,12], lr_factor = 0.1, warmup_step
= 7, warmup_lr = 0.1)
Review comment:
add a default test like: test_lr_sceduler(steps=[100, 200]) to test the
default parameters if user don't specify anything.
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