add convert xlm xl fairseq checkpoint to pytorch

src/transformers/models/xlm_roberta/convert_xlm_roberta_xl_original_pytorch_checkpoint_to_pytorch.py

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+# coding=utf-8
+# Copyright 2018 The HuggingFace Inc. team.
+#
+# 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.
+"""Convert RoBERTa checkpoint."""
+
+import argparse
+import pathlib
+
+import fairseq
+import torch
+from fairseq.models.roberta import RobertaModel as FairseqRobertaModel
+from fairseq.modules import TransformerSentenceEncoderLayer
+from packaging import version
+
+from transformers import XLMRobertaXLConfig, XLMRobertaXLForMaskedLM, XLMRobertaXLForSequenceClassification
+from transformers.models.bert.modeling_bert import (
+    BertIntermediate,
+    BertLayer,
+    BertOutput,
+    BertSelfAttention,
+    BertSelfOutput,
+)
+from transformers.utils import logging
+from transformers.models.roberta.modeling_roberta import RobertaAttention
+
+if version.parse(fairseq.__version__) < version.parse("1.0.0a"):
+    raise Exception("requires fairseq >= 1.0.0a")
+
+logging.set_verbosity_info()
+logger = logging.get_logger(__name__)
+
+SAMPLE_TEXT = "Hello world! cécé herlolip"
+
+
+def convert_xlm_roberta_xl_checkpoint_to_pytorch(
+        roberta_checkpoint_path: str, pytorch_dump_folder_path: str, classification_head: bool
+):
+    """
+    Copy/paste/tweak roberta's weights to our BERT structure.
+    """
+    roberta = FairseqRobertaModel.from_pretrained(roberta_checkpoint_path)
+    roberta.eval()  # disable dropout
+    roberta_sent_encoder = roberta.model.encoder.sentence_encoder
+    config = XLMRobertaXLConfig(
+        vocab_size=roberta_sent_encoder.embed_tokens.num_embeddings,
+        hidden_size=roberta.cfg.model.encoder_embed_dim,
+        num_hidden_layers=roberta.cfg.model.encoder_layers,
+        num_attention_heads=roberta.cfg.model.encoder_attention_heads,
+        intermediate_size=roberta.cfg.model.encoder_ffn_embed_dim,
+        max_position_embeddings=514,
+        type_vocab_size=1,
+        layer_norm_eps=1e-5,  # PyTorch default used in fairseq
+    )
+    if classification_head:
+        config.num_labels = roberta.model.classification_heads["mnli"].out_proj.weight.shape[0]
+
+    print("Our RoBERTa config:", config)
+
+    model = XLMRobertaXLForSequenceClassification(config) if classification_head else XLMRobertaXLForMaskedLM(config)
+    model.eval()
+
+    # Now let's copy all the weights.
+    # Embeddings
+    model.roberta.embeddings.word_embeddings.weight = roberta_sent_encoder.embed_tokens.weight
+    model.roberta.embeddings.position_embeddings.weight = roberta_sent_encoder.embed_positions.weight
+    model.roberta.embeddings.token_type_embeddings.weight.data = torch.zeros_like(
+        model.roberta.embeddings.token_type_embeddings.weight
+    )  # just zero them out b/c RoBERTa doesn't use them.
+
+
+    model.roberta.encoder.LayerNorm.weight = roberta_sent_encoder.layer_norm.weight
+    model.roberta.encoder.LayerNorm.bias = roberta_sent_encoder.layer_norm.bias
+
+    for i in range(config.num_hidden_layers):
+        # Encoder: start of layer
+        layer: BertLayer = model.roberta.encoder.layer[i]
+        roberta_layer: TransformerSentenceEncoderLayer = roberta_sent_encoder.layers[i]
+
+        attention: RobertaAttention = layer.attention
+        attention.self_attn_layer_norm.weight = roberta_layer.self_attn_layer_norm.weight
+        attention.self_attn_layer_norm.bias = roberta_layer.self_attn_layer_norm.bias
+
+        # self attention
+        self_attn: BertSelfAttention = layer.attention.self
+        assert (
+                roberta_layer.self_attn.k_proj.weight.data.shape
+                == roberta_layer.self_attn.q_proj.weight.data.shape
+                == roberta_layer.self_attn.v_proj.weight.data.shape
+                == torch.Size((config.hidden_size, config.hidden_size))
+        )
+
+        self_attn.query.weight.data = roberta_layer.self_attn.q_proj.weight
+        self_attn.query.bias.data = roberta_layer.self_attn.q_proj.bias
+        self_attn.key.weight.data = roberta_layer.self_attn.k_proj.weight
+        self_attn.key.bias.data = roberta_layer.self_attn.k_proj.bias
+        self_attn.value.weight.data = roberta_layer.self_attn.v_proj.weight
+        self_attn.value.bias.data = roberta_layer.self_attn.v_proj.bias
+
+        # self-attention output
+        self_output: BertSelfOutput = layer.attention.output
+        assert self_output.dense.weight.shape == roberta_layer.self_attn.out_proj.weight.shape
+        self_output.dense.weight = roberta_layer.self_attn.out_proj.weight
+        self_output.dense.bias = roberta_layer.self_attn.out_proj.bias
+
+        # this one is final layer norm
+        layer.LayerNorm.weight = roberta_layer.final_layer_norm.weight
+        layer.LayerNorm.bias = roberta_layer.final_layer_norm.bias
+
+        # intermediate
+        intermediate: BertIntermediate = layer.intermediate
+        assert intermediate.dense.weight.shape == roberta_layer.fc1.weight.shape
+        intermediate.dense.weight = roberta_layer.fc1.weight
+        intermediate.dense.bias = roberta_layer.fc1.bias
+
+        # output
+        bert_output: BertOutput = layer.output
+        assert bert_output.dense.weight.shape == roberta_layer.fc2.weight.shape
+        bert_output.dense.weight = roberta_layer.fc2.weight
+        bert_output.dense.bias = roberta_layer.fc2.bias
+        # end of layer
+
+    if classification_head:
+        model.classifier.dense.weight = roberta.model.classification_heads["mnli"].dense.weight
+        model.classifier.dense.bias = roberta.model.classification_heads["mnli"].dense.bias
+        model.classifier.out_proj.weight = roberta.model.classification_heads["mnli"].out_proj.weight
+        model.classifier.out_proj.bias = roberta.model.classification_heads["mnli"].out_proj.bias
+    else:
+        # LM Head
+        model.lm_head.dense.weight = roberta.model.encoder.lm_head.dense.weight
+        model.lm_head.dense.bias = roberta.model.encoder.lm_head.dense.bias
+        model.lm_head.layer_norm.weight = roberta.model.encoder.lm_head.layer_norm.weight
+        model.lm_head.layer_norm.bias = roberta.model.encoder.lm_head.layer_norm.bias
+        model.lm_head.decoder.weight = roberta.model.encoder.lm_head.weight
+        model.lm_head.decoder.bias = roberta.model.encoder.lm_head.bias
+
+    # Let's check that we get the same results.
+    input_ids: torch.Tensor = roberta.encode(SAMPLE_TEXT).unsqueeze(0)  # batch of size 1
+
+    our_output = model(input_ids)[0]
+    if classification_head:
+        their_output = roberta.model.classification_heads["mnli"](roberta.extract_features(input_ids))
+    else:
+        their_output = roberta.model(input_ids)[0]
+    print(our_output.shape, their_output.shape)
+    max_absolute_diff = torch.max(torch.abs(our_output - their_output)).item()
+    print(f"max_absolute_diff = {max_absolute_diff}")  # ~ 1e-7
+    success = torch.allclose(our_output, their_output, atol=1e-3)
+    print("Do both models output the same tensors?", "🔥" if success else "💩")
+    if not success:
+        raise Exception("Something went wRoNg")
+
+    pathlib.Path(pytorch_dump_folder_path).mkdir(parents=True, exist_ok=True)
+    print(f"Saving model to {pytorch_dump_folder_path}")
+    model.save_pretrained(pytorch_dump_folder_path)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    # Required parameters
+    parser.add_argument(
+        "--roberta_checkpoint_path", default=None, type=str, required=True, help="Path the official PyTorch dump."
+    )
+    parser.add_argument(
+        "--pytorch_dump_folder_path", default=None, type=str, required=True, help="Path to the output PyTorch model."
+    )
+    parser.add_argument(
+        "--classification_head", action="store_true", help="Whether to convert a final classification head."
+    )
+    args = parser.parse_args()
+    convert_xlm_roberta_xl_checkpoint_to_pytorch(
+        args.roberta_checkpoint_path, args.pytorch_dump_folder_path, args.classification_head
+    )