[Flax] Add Electra models (#11426)

* add electra model to flax

* Remove Electra Next Sentence Prediction model added by mistake

* fix parameter sharing and loosen equality threshold

* fix styling issues

* add mistaken removen imports

* fix electra table

* Add FlaxElectra to automodels and fixe docs

* fix issues pointed out the PR

* fix flax electra to comply with latest changes

* remove stale class

* add copied from
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

docs/source/index.rst

@@ -295,7 +295,7 @@ Flax), PyTorch, and/or TensorFlow.
 +-----------------------------+----------------+----------------+-----------------+--------------------+--------------+
 |         DistilBERT          |       ✅       |       ✅       |       ✅        |         ✅         |      ❌      |
 +-----------------------------+----------------+----------------+-----------------+--------------------+--------------+
-|           ELECTRA           |       ✅       |       ✅       |       ✅        |         ✅         |      ❌      |
+|           ELECTRA           |       ✅       |       ✅       |       ✅        |         ✅         |      ✅      |
 +-----------------------------+----------------+----------------+-----------------+--------------------+--------------+
 |       Encoder decoder       |       ❌       |       ❌       |       ✅        |         ❌         |      ❌      |
 +-----------------------------+----------------+----------------+-----------------+--------------------+--------------+

docs/source/model_doc/electra.rst

@@ -185,3 +185,52 @@ TFElectraForQuestionAnswering
 
 .. autoclass:: transformers.TFElectraForQuestionAnswering
     :members: call
+
+
+FlaxElectraModel
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FlaxElectraModel
+    :members: __call__
+
+
+FlaxElectraForPreTraining
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FlaxElectraForPreTraining
+    :members: __call__
+
+
+FlaxElectraForMaskedLM
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FlaxElectraForMaskedLM
+    :members: __call__
+
+
+FlaxElectraForSequenceClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FlaxElectraForSequenceClassification
+    :members: __call__
+
+
+FlaxElectraForMultipleChoice
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FlaxElectraForMultipleChoice
+    :members: __call__
+
+
+FlaxElectraForTokenClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FlaxElectraForTokenClassification
+    :members: __call__
+
+
+FlaxElectraForQuestionAnswering
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FlaxElectraForQuestionAnswering
+    :members: __call__

src/transformers/__init__.py

@@ -1403,6 +1403,18 @@ if is_flax_available():
             "FlaxBertPreTrainedModel",
         ]
     )
+    _import_structure["models.electra"].extend(
+        [
+            "FlaxElectraForMaskedLM",
+            "FlaxElectraForMultipleChoice",
+            "FlaxElectraForPreTraining",
+            "FlaxElectraForQuestionAnswering",
+            "FlaxElectraForSequenceClassification",
+            "FlaxElectraForTokenClassification",
+            "FlaxElectraModel",
+            "FlaxElectraPreTrainedModel",
+        ]
+    )
     _import_structure["models.roberta"].extend(
         [
             "FlaxRobertaForMaskedLM",
@@ -2585,6 +2597,16 @@ if TYPE_CHECKING:
             FlaxBertModel,
             FlaxBertPreTrainedModel,
         )
+        from .models.electra import (
+            FlaxElectraForMaskedLM,
+            FlaxElectraForMultipleChoice,
+            FlaxElectraForPreTraining,
+            FlaxElectraForQuestionAnswering,
+            FlaxElectraForSequenceClassification,
+            FlaxElectraForTokenClassification,
+            FlaxElectraModel,
+            FlaxElectraPreTrainedModel,
+        )
         from .models.roberta import (
             FlaxRobertaForMaskedLM,
             FlaxRobertaForMultipleChoice,

src/transformers/models/auto/modeling_flax_auto.py

@@ -28,6 +28,15 @@ from ..bert.modeling_flax_bert import (
     FlaxBertForTokenClassification,
     FlaxBertModel,
 )
+from ..electra.modeling_flax_electra import (
+    FlaxElectraForMaskedLM,
+    FlaxElectraForMultipleChoice,
+    FlaxElectraForPreTraining,
+    FlaxElectraForQuestionAnswering,
+    FlaxElectraForSequenceClassification,
+    FlaxElectraForTokenClassification,
+    FlaxElectraModel,
+)
 from ..roberta.modeling_flax_roberta import (
     FlaxRobertaForMaskedLM,
     FlaxRobertaForMultipleChoice,
@@ -37,7 +46,7 @@ from ..roberta.modeling_flax_roberta import (
     FlaxRobertaModel,
 )
 from .auto_factory import auto_class_factory
-from .configuration_auto import BertConfig, RobertaConfig
+from .configuration_auto import BertConfig, ElectraConfig, RobertaConfig
 
 
 logger = logging.get_logger(__name__)
@@ -48,6 +57,7 @@ FLAX_MODEL_MAPPING = OrderedDict(
         # Base model mapping
         (RobertaConfig, FlaxRobertaModel),
         (BertConfig, FlaxBertModel),
+        (ElectraConfig, FlaxElectraModel),
     ]
 )
 
@@ -56,6 +66,7 @@ FLAX_MODEL_FOR_PRETRAINING_MAPPING = OrderedDict(
         # Model for pre-training mapping
         (RobertaConfig, FlaxRobertaForMaskedLM),
         (BertConfig, FlaxBertForPreTraining),
+        (ElectraConfig, FlaxElectraForPreTraining),
     ]
 )
 
@@ -64,6 +75,7 @@ FLAX_MODEL_FOR_MASKED_LM_MAPPING = OrderedDict(
         # Model for Masked LM mapping
         (RobertaConfig, FlaxRobertaForMaskedLM),
         (BertConfig, FlaxBertForMaskedLM),
+        (ElectraConfig, FlaxElectraForMaskedLM),
     ]
 )
 
@@ -72,6 +84,7 @@ FLAX_MODEL_FOR_SEQUENCE_CLASSIFICATION_MAPPING = OrderedDict(
         # Model for Sequence Classification mapping
         (RobertaConfig, FlaxRobertaForSequenceClassification),
         (BertConfig, FlaxBertForSequenceClassification),
+        (ElectraConfig, FlaxElectraForSequenceClassification),
     ]
 )
 
@@ -80,6 +93,7 @@ FLAX_MODEL_FOR_QUESTION_ANSWERING_MAPPING = OrderedDict(
         # Model for Question Answering mapping
         (RobertaConfig, FlaxRobertaForQuestionAnswering),
         (BertConfig, FlaxBertForQuestionAnswering),
+        (ElectraConfig, FlaxElectraForQuestionAnswering),
     ]
 )
 
@@ -88,6 +102,7 @@ FLAX_MODEL_FOR_TOKEN_CLASSIFICATION_MAPPING = OrderedDict(
         # Model for Token Classification mapping
         (RobertaConfig, FlaxRobertaForTokenClassification),
         (BertConfig, FlaxBertForTokenClassification),
+        (ElectraConfig, FlaxElectraForTokenClassification),
     ]
 )
 
@@ -96,6 +111,7 @@ FLAX_MODEL_FOR_MULTIPLE_CHOICE_MAPPING = OrderedDict(
         # Model for Multiple Choice mapping
         (RobertaConfig, FlaxRobertaForMultipleChoice),
         (BertConfig, FlaxBertForMultipleChoice),
+        (ElectraConfig, FlaxElectraForMultipleChoice),
     ]
 )
 

src/transformers/models/electra/__init__.py

@@ -18,7 +18,13 @@
 
 from typing import TYPE_CHECKING
 
-from ...file_utils import _BaseLazyModule, is_tf_available, is_tokenizers_available, is_torch_available
+from ...file_utils import (
+    _BaseLazyModule,
+    is_flax_available,
+    is_tf_available,
+    is_tokenizers_available,
+    is_torch_available,
+)
 
 
 _import_structure = {
@@ -56,6 +62,18 @@ if is_tf_available():
         "TFElectraPreTrainedModel",
     ]
 
+if is_flax_available():
+    _import_structure["modeling_flax_electra"] = [
+        "FlaxElectraForMaskedLM",
+        "FlaxElectraForMultipleChoice",
+        "FlaxElectraForPreTraining",
+        "FlaxElectraForQuestionAnswering",
+        "FlaxElectraForSequenceClassification",
+        "FlaxElectraForTokenClassification",
+        "FlaxElectraModel",
+        "FlaxElectraPreTrainedModel",
+    ]
+
 
 if TYPE_CHECKING:
     from .configuration_electra import ELECTRA_PRETRAINED_CONFIG_ARCHIVE_MAP, ElectraConfig
@@ -91,6 +109,18 @@ if TYPE_CHECKING:
             TFElectraPreTrainedModel,
         )
 
+    if is_flax_available():
+        from .modeling_flax_electra import (
+            FlaxElectraForMaskedLM,
+            FlaxElectraForMultipleChoice,
+            FlaxElectraForPreTraining,
+            FlaxElectraForQuestionAnswering,
+            FlaxElectraForSequenceClassification,
+            FlaxElectraForTokenClassification,
+            FlaxElectraModel,
+            FlaxElectraPreTrainedModel,
+        )
+
 else:
     import importlib
     import os

src/transformers/utils/dummy_flax_objects.py

@@ -180,6 +180,74 @@ class FlaxBertPreTrainedModel:
         requires_backends(self, ["flax"])
 
 
+class FlaxElectraForMaskedLM:
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+    @classmethod
+    def from_pretrained(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+
+class FlaxElectraForMultipleChoice:
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+    @classmethod
+    def from_pretrained(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+
+class FlaxElectraForPreTraining:
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+
+class FlaxElectraForQuestionAnswering:
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+    @classmethod
+    def from_pretrained(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+
+class FlaxElectraForSequenceClassification:
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+    @classmethod
+    def from_pretrained(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+
+class FlaxElectraForTokenClassification:
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+    @classmethod
+    def from_pretrained(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+
+class FlaxElectraModel:
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+    @classmethod
+    def from_pretrained(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+
+class FlaxElectraPreTrainedModel:
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+    @classmethod
+    def from_pretrained(self, *args, **kwargs):
+        requires_backends(self, ["flax"])
+
+
 class FlaxRobertaForMaskedLM:
     def __init__(self, *args, **kwargs):
         requires_backends(self, ["flax"])

tests/test_modeling_flax_electra.py

+import unittest
+
+import numpy as np
+
+from transformers import ElectraConfig, is_flax_available
+from transformers.testing_utils import require_flax, slow
+
+from .test_modeling_flax_common import FlaxModelTesterMixin, ids_tensor, random_attention_mask
+
+
+if is_flax_available():
+    from transformers.models.electra.modeling_flax_electra import (
+        FlaxElectraForMaskedLM,
+        FlaxElectraForMultipleChoice,
+        FlaxElectraForPreTraining,
+        FlaxElectraForQuestionAnswering,
+        FlaxElectraForSequenceClassification,
+        FlaxElectraForTokenClassification,
+        FlaxElectraModel,
+    )
+
+
+class FlaxElectraModelTester(unittest.TestCase):
+    def __init__(
+        self,
+        parent,
+        batch_size=13,
+        seq_length=7,
+        is_training=True,
+        use_attention_mask=True,
+        use_token_type_ids=True,
+        use_labels=True,
+        vocab_size=99,
+        embedding_size=24,
+        hidden_size=32,
+        num_hidden_layers=5,
+        num_attention_heads=4,
+        intermediate_size=37,
+        hidden_act="gelu",
+        hidden_dropout_prob=0.1,
+        attention_probs_dropout_prob=0.1,
+        max_position_embeddings=512,
+        type_vocab_size=16,
+        type_sequence_label_size=2,
+        initializer_range=0.02,
+        num_choices=4,
+    ):
+        self.parent = parent
+        self.batch_size = batch_size
+        self.seq_length = seq_length
+        self.is_training = is_training
+        self.use_attention_mask = use_attention_mask
+        self.use_token_type_ids = use_token_type_ids
+        self.use_labels = use_labels
+        self.vocab_size = vocab_size
+        self.hidden_size = hidden_size
+        self.embedding_size = embedding_size
+        self.num_hidden_layers = num_hidden_layers
+        self.num_attention_heads = num_attention_heads
+        self.intermediate_size = intermediate_size
+        self.hidden_act = hidden_act
+        self.hidden_dropout_prob = hidden_dropout_prob
+        self.attention_probs_dropout_prob = attention_probs_dropout_prob
+        self.max_position_embeddings = max_position_embeddings
+        self.type_vocab_size = type_vocab_size
+        self.type_sequence_label_size = type_sequence_label_size
+        self.initializer_range = initializer_range
+        self.num_choices = num_choices
+
+    def prepare_config_and_inputs(self):
+        input_ids = ids_tensor([self.batch_size, self.seq_length], self.vocab_size)
+
+        attention_mask = None
+        if self.use_attention_mask:
+            attention_mask = random_attention_mask([self.batch_size, self.seq_length])
+
+        token_type_ids = None
+        if self.use_token_type_ids:
+            token_type_ids = ids_tensor([self.batch_size, self.seq_length], self.type_vocab_size)
+
+        config = ElectraConfig(
+            vocab_size=self.vocab_size,
+            hidden_size=self.hidden_size,
+            embedding_size=self.embedding_size,
+            num_hidden_layers=self.num_hidden_layers,
+            num_attention_heads=self.num_attention_heads,
+            intermediate_size=self.intermediate_size,
+            hidden_act=self.hidden_act,
+            hidden_dropout_prob=self.hidden_dropout_prob,
+            attention_probs_dropout_prob=self.attention_probs_dropout_prob,
+            max_position_embeddings=self.max_position_embeddings,
+            type_vocab_size=self.type_vocab_size,
+            initializer_range=self.initializer_range,
+        )
+
+        return config, input_ids, token_type_ids, attention_mask
+
+    def prepare_config_and_inputs_for_common(self):
+        config_and_inputs = self.prepare_config_and_inputs()
+        config, input_ids, token_type_ids, attention_mask = config_and_inputs
+        inputs_dict = {"input_ids": input_ids, "token_type_ids": token_type_ids, "attention_mask": attention_mask}
+        return config, inputs_dict
+
+
+@require_flax
+class FlaxElectraModelTest(FlaxModelTesterMixin, unittest.TestCase):
+
+    all_model_classes = (
+        (
+            FlaxElectraModel,
+            FlaxElectraForMaskedLM,
+            FlaxElectraForPreTraining,
+            FlaxElectraForTokenClassification,
+            FlaxElectraForQuestionAnswering,
+            FlaxElectraForMultipleChoice,
+            FlaxElectraForSequenceClassification,
+        )
+        if is_flax_available()
+        else ()
+    )
+
+    def setUp(self):
+        self.model_tester = FlaxElectraModelTester(self)
+
+    @slow
+    def test_model_from_pretrained(self):
+        for model_class_name in self.all_model_classes:
+            if model_class_name == FlaxElectraForMaskedLM:
+                model = model_class_name.from_pretrained("google/electra-small-generator")
+            else:
+                model = model_class_name.from_pretrained("google/electra-small-discriminator")
+            outputs = model(np.ones((1, 1)))
+            self.assertIsNotNone(outputs)