bert: add conversion script for BERT Token Dropping TF2 checkpoints (#17142)

* bert: add conversion script for BERT Token Dropping TF2 checkpoints

* bert: rename conversion script for BERT Token Dropping checkpoints

* bert: fix flake errors in BERT Token Dropping conversion script

* bert: make doc-builder happy!!1!11

* bert: fix pytorch_dump_path of BERT Token Dropping conversion script

src/transformers/models/bert/convert_bert_token_dropping_original_tf2_checkpoint_to_pytorch.py

+# Copyright 2022 The HuggingFace Team. 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.
+
+"""
+This script converts a lm-head checkpoint from the "Token Dropping" implementation into a PyTorch-compatible BERT
+model. The official implementation of "Token Dropping" can be found in the TensorFlow Models repository:
+
+https://github.com/tensorflow/models/tree/master/official/projects/token_dropping
+"""
+import argparse
+
+import tensorflow as tf
+import torch
+
+from transformers import BertConfig, BertForMaskedLM
+from transformers.models.bert.modeling_bert import (
+    BertIntermediate,
+    BertLayer,
+    BertOutput,
+    BertPooler,
+    BertSelfAttention,
+    BertSelfOutput,
+)
+from transformers.utils import logging
+
+
+logging.set_verbosity_info()
+
+
+def convert_checkpoint_to_pytorch(tf_checkpoint_path: str, config_path: str, pytorch_dump_path: str):
+    def get_masked_lm_array(name: str):
+        full_name = f"masked_lm/{name}/.ATTRIBUTES/VARIABLE_VALUE"
+        array = tf.train.load_variable(tf_checkpoint_path, full_name)
+
+        if "kernel" in name:
+            array = array.transpose()
+
+        return torch.from_numpy(array)
+
+    def get_encoder_array(name: str):
+        full_name = f"encoder/{name}/.ATTRIBUTES/VARIABLE_VALUE"
+        array = tf.train.load_variable(tf_checkpoint_path, full_name)
+
+        if "kernel" in name:
+            array = array.transpose()
+
+        return torch.from_numpy(array)
+
+    def get_encoder_layer_array(layer_index: int, name: str):
+        full_name = f"encoder/_transformer_layers/{layer_index}/{name}/.ATTRIBUTES/VARIABLE_VALUE"
+        array = tf.train.load_variable(tf_checkpoint_path, full_name)
+
+        if "kernel" in name:
+            array = array.transpose()
+
+        return torch.from_numpy(array)
+
+    def get_encoder_attention_layer_array(layer_index: int, name: str, orginal_shape):
+        full_name = f"encoder/_transformer_layers/{layer_index}/_attention_layer/{name}/.ATTRIBUTES/VARIABLE_VALUE"
+        array = tf.train.load_variable(tf_checkpoint_path, full_name)
+        array = array.reshape(orginal_shape)
+
+        if "kernel" in name:
+            array = array.transpose()
+
+        return torch.from_numpy(array)
+
+    print(f"Loading model based on config from {config_path}...")
+    config = BertConfig.from_json_file(config_path)
+    model = BertForMaskedLM(config)
+
+    # Layers
+    for layer_index in range(0, config.num_hidden_layers):
+        layer: BertLayer = model.bert.encoder.layer[layer_index]
+
+        # Self-attention
+        self_attn: BertSelfAttention = layer.attention.self
+
+        self_attn.query.weight.data = get_encoder_attention_layer_array(
+            layer_index, "_query_dense/kernel", self_attn.query.weight.data.shape
+        )
+        self_attn.query.bias.data = get_encoder_attention_layer_array(
+            layer_index, "_query_dense/bias", self_attn.query.bias.data.shape
+        )
+        self_attn.key.weight.data = get_encoder_attention_layer_array(
+            layer_index, "_key_dense/kernel", self_attn.key.weight.data.shape
+        )
+        self_attn.key.bias.data = get_encoder_attention_layer_array(
+            layer_index, "_key_dense/bias", self_attn.key.bias.data.shape
+        )
+        self_attn.value.weight.data = get_encoder_attention_layer_array(
+            layer_index, "_value_dense/kernel", self_attn.value.weight.data.shape
+        )
+        self_attn.value.bias.data = get_encoder_attention_layer_array(
+            layer_index, "_value_dense/bias", self_attn.value.bias.data.shape
+        )
+
+        # Self-attention Output
+        self_output: BertSelfOutput = layer.attention.output
+
+        self_output.dense.weight.data = get_encoder_attention_layer_array(
+            layer_index, "_output_dense/kernel", self_output.dense.weight.data.shape
+        )
+        self_output.dense.bias.data = get_encoder_attention_layer_array(
+            layer_index, "_output_dense/bias", self_output.dense.bias.data.shape
+        )
+
+        self_output.LayerNorm.weight.data = get_encoder_layer_array(layer_index, "_attention_layer_norm/gamma")
+        self_output.LayerNorm.bias.data = get_encoder_layer_array(layer_index, "_attention_layer_norm/beta")
+
+        # Intermediate
+        intermediate: BertIntermediate = layer.intermediate
+
+        intermediate.dense.weight.data = get_encoder_layer_array(layer_index, "_intermediate_dense/kernel")
+        intermediate.dense.bias.data = get_encoder_layer_array(layer_index, "_intermediate_dense/bias")
+
+        # Output
+        bert_output: BertOutput = layer.output
+
+        bert_output.dense.weight.data = get_encoder_layer_array(layer_index, "_output_dense/kernel")
+        bert_output.dense.bias.data = get_encoder_layer_array(layer_index, "_output_dense/bias")
+
+        bert_output.LayerNorm.weight.data = get_encoder_layer_array(layer_index, "_output_layer_norm/gamma")
+        bert_output.LayerNorm.bias.data = get_encoder_layer_array(layer_index, "_output_layer_norm/beta")
+
+    # Embeddings
+    model.bert.embeddings.position_embeddings.weight.data = get_encoder_array("_position_embedding_layer/embeddings")
+    model.bert.embeddings.token_type_embeddings.weight.data = get_encoder_array("_type_embedding_layer/embeddings")
+    model.bert.embeddings.LayerNorm.weight.data = get_encoder_array("_embedding_norm_layer/gamma")
+    model.bert.embeddings.LayerNorm.bias.data = get_encoder_array("_embedding_norm_layer/beta")
+
+    # LM Head
+    lm_head = model.cls.predictions.transform
+
+    lm_head.dense.weight.data = get_masked_lm_array("dense/kernel")
+    lm_head.dense.bias.data = get_masked_lm_array("dense/bias")
+
+    lm_head.LayerNorm.weight.data = get_masked_lm_array("layer_norm/gamma")
+    lm_head.LayerNorm.bias.data = get_masked_lm_array("layer_norm/beta")
+
+    model.bert.embeddings.word_embeddings.weight.data = get_masked_lm_array("embedding_table")
+
+    # Pooling
+    model.bert.pooler = BertPooler(config=config)
+    model.bert.pooler.dense.weight.data: BertPooler = get_encoder_array("_pooler_layer/kernel")
+    model.bert.pooler.dense.bias.data: BertPooler = get_encoder_array("_pooler_layer/bias")
+
+    # Export final model
+    model.save_pretrained(pytorch_dump_path)
+
+    # Integration test - should load without any errors ;)
+    new_model = BertForMaskedLM.from_pretrained(pytorch_dump_path)
+    print(new_model.eval())
+
+    print("Model conversion was done sucessfully!")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--tf_checkpoint_path", type=str, required=True, help="Path to the TensorFlow Token Dropping checkpoint path."
+    )
+    parser.add_argument(
+        "--bert_config_file",
+        type=str,
+        required=True,
+        help="The config json file corresponding to the BERT model. This specifies the model architecture.",
+    )
+    parser.add_argument(
+        "--pytorch_dump_path",
+        type=str,
+        required=True,
+        help="Path to the output PyTorch model.",
+    )
+    args = parser.parse_args()
+    convert_checkpoint_to_pytorch(args.tf_checkpoint_path, args.bert_config_file, args.pytorch_dump_path)