Add DeeBERT (entropy-based early exiting for *BERT) (#5477)

* Add deebert code

* Add readme of deebert

* Add test for deebert

Update test for Deebert

* Update DeeBert (README, class names, function refactoring); remove requirements.txt

* Format update

* Update test

* Update readme and model init methods

examples/deebert/test_glue_deebert.py

@@ -0,0 +1,97 @@
+import argparse
+import logging
+import sys
+import unittest
+from unittest.mock import patch
+
+import run_glue_deebert
+
+
+logging.basicConfig(level=logging.DEBUG)
+
+logger = logging.getLogger()
+
+
+def get_setup_file():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-f")
+    args = parser.parse_args()
+    return args.f
+
+
+class DeeBertTests(unittest.TestCase):
+    def test_glue_deebert(self):
+        stream_handler = logging.StreamHandler(sys.stdout)
+        logger.addHandler(stream_handler)
+
+        train_args = """
+            run_glue_deebert.py
+            --model_type roberta
+            --model_name_or_path roberta-base
+            --task_name MRPC
+            --do_train
+            --do_eval
+            --do_lower_case
+            --data_dir ./tests/fixtures/tests_samples/MRPC/
+            --max_seq_length 128
+            --per_gpu_eval_batch_size=1
+            --per_gpu_train_batch_size=8
+            --learning_rate 2e-4
+            --num_train_epochs 3
+            --overwrite_output_dir
+            --seed 42
+            --output_dir ./examples/deebert/saved_models/roberta-base/MRPC/two_stage
+            --plot_data_dir ./examples/deebert/results/
+            --save_steps 0
+            --overwrite_cache
+            --eval_after_first_stage
+            """.split()
+
+        eval_args = """
+            run_glue_deebert.py
+            --model_type roberta
+            --model_name_or_path ./examples/deebert/saved_models/roberta-base/MRPC/two_stage
+            --task_name MRPC
+            --do_eval
+            --do_lower_case
+            --data_dir ./tests/fixtures/tests_samples/MRPC/
+            --output_dir ./examples/deebert/saved_models/roberta-base/MRPC/two_stage
+            --plot_data_dir ./examples/deebert/results/
+            --max_seq_length 128
+            --eval_each_highway
+            --eval_highway
+            --overwrite_cache
+            --per_gpu_eval_batch_size=1
+            """.split()
+
+        entropy_eval_args = """
+            run_glue_deebert.py
+            --model_type roberta
+            --model_name_or_path ./examples/deebert/saved_models/roberta-base/MRPC/two_stage
+            --task_name MRPC
+            --do_eval
+            --do_lower_case
+            --data_dir ./tests/fixtures/tests_samples/MRPC/
+            --output_dir ./examples/deebert/saved_models/roberta-base/MRPC/two_stage
+            --plot_data_dir ./examples/deebert/results/
+            --max_seq_length 128
+            --early_exit_entropy 0.1
+            --eval_highway
+            --overwrite_cache
+            --per_gpu_eval_batch_size=1
+            """.split()
+
+        with patch.object(sys, "argv", train_args):
+            result = run_glue_deebert.main()
+            for value in result.values():
+                self.assertGreaterEqual(value, 0.75)
+
+        with patch.object(sys, "argv", eval_args):
+            result = run_glue_deebert.main()
+            for value in result.values():
+                self.assertGreaterEqual(value, 0.75)
+
+        with patch.object(sys, "argv", entropy_eval_args):
+            result = run_glue_deebert.main()
+            for value in result.values():
+                self.assertGreaterEqual(value, 0.75)