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attn_mask_utils.py

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+from typing import List, Optional, Tuple, Union
+import torch
+from transformers.modeling_attn_mask_utils import AttentionMaskConverter
+
+
+def _prepare_4d_causal_attention_mask(
+    attention_mask: Optional[torch.Tensor],
+    input_shape: Union[torch.Size, Tuple, List],
+    inputs_embeds: torch.Tensor,
+    past_key_values_length: int,
+    sliding_window: Optional[int] = None,
+):
+    """
+    Creates a causal 4D mask of shape `(batch_size, 1, query_length, key_value_length)` from a 2D mask of shape
+    `(batch_size, key_value_length)`
+
+    Args:
+        attention_mask (`torch.Tensor` or `None`):
+            A 2D attention mask of shape `(batch_size, key_value_length)`
+        input_shape (`tuple(int)` or `list(int)` or `torch.Size`):
+            The input shape should be a tuple that defines `(batch_size, query_length)`.
+        inputs_embeds (`torch.Tensor`):
+            The embedded inputs as a torch Tensor.
+        past_key_values_length (`int`):
+            The length of the key value cache.
+        sliding_window (`int`, *optional*):
+            If the model uses windowed attention, a sliding window should be passed.
+    """
+    attn_mask_converter = AttentionMaskConverter(
+        is_causal=False, sliding_window=sliding_window
+    )  # is_causal=True in original implementation
+
+    key_value_length = input_shape[-1] + past_key_values_length
+
+    # 4d mask is passed through the layers
+    if attention_mask is not None and len(attention_mask.shape) == 2:
+        attention_mask = attn_mask_converter.to_4d(
+            attention_mask,
+            input_shape[-1],
+            key_value_length=key_value_length,
+            dtype=inputs_embeds.dtype,
+        )
+    elif attention_mask is not None and len(attention_mask.shape) == 4:
+        expected_shape = (input_shape[0], 1, input_shape[1], key_value_length)
+        if tuple(attention_mask.shape) != expected_shape:
+            raise ValueError(
+                f"Incorrect 4D attention_mask shape: {tuple(attention_mask.shape)}; expected: {expected_shape}."
+            )
+        else:
+            # if the 4D mask has correct shape - invert it and fill with negative infinity
+            inverted_mask = 1.0 - attention_mask
+            attention_mask = inverted_mask.masked_fill(
+                inverted_mask.to(torch.bool), torch.finfo(inputs_embeds.dtype).min
+            )
+    else:
+        attention_mask = attn_mask_converter.to_causal_4d(
+            input_shape[0],
+            input_shape[-1],
+            key_value_length,
+            dtype=inputs_embeds.dtype,
+            device=inputs_embeds.device,
+        )
+
+    return attention_mask
+
+
+# Adapted from _prepare_4d_causal_attention_mask
+def _prepare_4d_causal_attention_mask_for_sdpa(
+    attention_mask: Optional[torch.Tensor],
+    input_shape: Union[torch.Size, Tuple, List],
+    inputs_embeds: torch.Tensor,
+    past_key_values_length: int,
+    sliding_window: Optional[int] = None,
+):
+    """
+    Prepares the correct `attn_mask` argument to be used by `torch.nn.functional.scaled_dot_product_attention`.
+
+    In case no token is masked in the `attention_mask` argument, we simply set it to `None` for the cases `query_length == 1` and
+    `key_value_length == query_length`, and rely instead on SDPA `is_causal` argument to use causal/non-causal masks,
+    allowing to dispatch to the flash attention kernel (that can otherwise not be used if a custom `attn_mask` is passed).
+    """
+    attn_mask_converter = AttentionMaskConverter(
+        is_causal=False, sliding_window=sliding_window
+    )  # is_causal=True in original implementation
+
+    key_value_length = input_shape[-1] + past_key_values_length
+    batch_size, query_length = input_shape
+
+    # torch.jit.trace, symbolic_trace and torchdynamo with fullgraph=True are unable to capture the controlflow `is_causal=attention_mask is None and q_len > 1`
+    # used as an SDPA argument. We keep compatibility with these tracing tools by always using SDPA's `attn_mask` argument in case we are tracing.
+    # TODO: For dynamo, rather use a check on fullgraph=True once this is possible (https://github.com/pytorch/pytorch/pull/120400).
+    is_tracing = (
+        torch.jit.is_tracing()
+        or isinstance(inputs_embeds, torch.fx.Proxy)
+        or (hasattr(torch, "_dynamo") and torch._dynamo.is_compiling())
+    )
+
+    if attention_mask is not None:
+        # 4d mask is passed through
+        if len(attention_mask.shape) == 4:
+            expected_shape = (input_shape[0], 1, input_shape[1], key_value_length)
+            if tuple(attention_mask.shape) != expected_shape:
+                raise ValueError(
+                    f"Incorrect 4D attention_mask shape: {tuple(attention_mask.shape)}; expected: {expected_shape}."
+                )
+            else:
+                # if the 4D mask has correct shape - invert it and fill with negative infinity
+                inverted_mask = 1.0 - attention_mask.to(inputs_embeds.dtype)
+                attention_mask = inverted_mask.masked_fill(
+                    inverted_mask.to(torch.bool), torch.finfo(inputs_embeds.dtype).min
+                )
+                return attention_mask
+
+        elif not is_tracing and torch.all(attention_mask == 1):
+            if query_length == 1:
+                # For query_length == 1, causal attention and bi-directional attention are the same.
+                attention_mask = None
+            elif key_value_length == query_length:
+                attention_mask = None
+            else:
+                # Unfortunately, for query_length > 1 and key_value_length != query_length, we cannot generally ignore the attention mask, as SDPA causal mask generation
+                # may be wrong. We will set `is_causal=False` in SDPA and rely on Transformers attention_mask instead, hence not setting it to None here.
+                # Reference: https://github.com/pytorch/pytorch/issues/108108
+                pass
+    elif query_length > 1 and key_value_length != query_length:
+        # See the comment above (https://github.com/pytorch/pytorch/issues/108108).
+        # Ugly: we set it to True here to dispatch in the following controlflow to `to_causal_4d`.
+        attention_mask = True
+    elif is_tracing:
+        raise ValueError(
+            'Attention using SDPA can not be traced with torch.jit.trace when no attention_mask is provided. To solve this issue, please either load your model with the argument `attn_implementation="eager"` or pass an attention_mask input when tracing the model.'
+        )
+
+    if attention_mask is None:
+        expanded_4d_mask = None
+    elif attention_mask is True:
+        expanded_4d_mask = attn_mask_converter.to_causal_4d(
+            input_shape[0],
+            input_shape[-1],
+            key_value_length,
+            dtype=inputs_embeds.dtype,
+            device=inputs_embeds.device,
+        )
+    else:
+        expanded_4d_mask = attn_mask_converter.to_4d(
+            attention_mask,
+            input_shape[-1],
+            dtype=inputs_embeds.dtype,
+            key_value_length=key_value_length,
+        )
+
+        # Attend to all tokens in masked rows from the causal_mask, for example the relevant first rows when
+        # using left padding. This is required by F.scaled_dot_product_attention memory-efficient attention path.
+        # Details: https://github.com/pytorch/pytorch/issues/110213
+        if not is_tracing and expanded_4d_mask.device.type == "cuda":
+            expanded_4d_mask = AttentionMaskConverter._unmask_unattended(
+                expanded_4d_mask, min_dtype=torch.finfo(inputs_embeds.dtype).min
+            )
+
+    return expanded_4d_mask

bidirectional_mistral.py

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+from typing import List, Optional, Tuple, Union
+import torch
+
+from transformers import (
+    MistralModel,
+    MistralPreTrainedModel,
+    MistralForCausalLM,
+    MistralConfig,
+)
+from transformers.modeling_outputs import BaseModelOutputWithPast
+from transformers.cache_utils import Cache, DynamicCache
+from transformers.models.mistral.modeling_mistral import (
+    MistralDecoderLayer,
+    MistralRMSNorm,
+    MistralAttention,
+    MistralFlashAttention2,
+    MistralSdpaAttention,
+    MistralMLP,
+)
+from torch import nn
+from transformers.utils import logging
+from attn_mask_utils import (
+    _prepare_4d_causal_attention_mask,
+    _prepare_4d_causal_attention_mask_for_sdpa,
+)
+
+logger = logging.get_logger(__name__)
+
+
+class ModifiedMistralAttention(MistralAttention):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.is_causal = False
+
+
+class ModifiedMistralFlashAttention2(MistralFlashAttention2):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.is_causal = False
+
+
+class ModifiedMistralSdpaAttention(MistralSdpaAttention):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.is_causal = False
+
+
+MISTRAL_ATTENTION_CLASSES = {
+    "eager": ModifiedMistralAttention,
+    "flash_attention_2": ModifiedMistralFlashAttention2,
+    "sdpa": ModifiedMistralSdpaAttention,
+}
+
+
+class ModifiedMistralDecoderLayer(MistralDecoderLayer):
+    def __init__(self, config: MistralConfig, layer_idx: int):
+        nn.Module.__init__(self)
+        self.hidden_size = config.hidden_size
+
+        self.self_attn = MISTRAL_ATTENTION_CLASSES[config._attn_implementation](
+            config, layer_idx
+        )
+
+        self.mlp = MistralMLP(config)
+        self.input_layernorm = MistralRMSNorm(
+            config.hidden_size, eps=config.rms_norm_eps
+        )
+        self.post_attention_layernorm = MistralRMSNorm(
+            config.hidden_size, eps=config.rms_norm_eps
+        )
+
+
+class MistralBiModel(MistralModel):
+    def __init__(self, config: MistralConfig):
+        MistralPreTrainedModel.__init__(self, config)
+        self.padding_idx = config.pad_token_id
+        self.vocab_size = config.vocab_size
+
+        self.embed_tokens = nn.Embedding(
+            config.vocab_size, config.hidden_size, self.padding_idx
+        )
+        self.layers = nn.ModuleList(
+            [
+                ModifiedMistralDecoderLayer(config, layer_idx)
+                for layer_idx in range(config.num_hidden_layers)
+            ]
+        )
+        self._attn_implementation = config._attn_implementation
+        self.norm = MistralRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
+
+        self.gradient_checkpointing = False
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    # Copied from forward() in transformers.models.mistral.modeling_mistral.MistralModel
+    def forward(
+        self,
+        input_ids: torch.LongTensor = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_values: Optional[List[torch.FloatTensor]] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+        use_cache: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+    ) -> Union[Tuple, BaseModelOutputWithPast]:
+        output_attentions = (
+            output_attentions
+            if output_attentions is not None
+            else self.config.output_attentions
+        )
+        output_hidden_states = (
+            output_hidden_states
+            if output_hidden_states is not None
+            else self.config.output_hidden_states
+        )
+        use_cache = use_cache if use_cache is not None else self.config.use_cache
+
+        return_dict = (
+            return_dict if return_dict is not None else self.config.use_return_dict
+        )
+
+        # retrieve input_ids and inputs_embeds
+        if input_ids is not None and inputs_embeds is not None:
+            raise ValueError(
+                "You cannot specify both decoder_input_ids and decoder_inputs_embeds at the same time"
+            )
+        elif input_ids is not None:
+            batch_size, seq_length = input_ids.shape
+        elif inputs_embeds is not None:
+            batch_size, seq_length, _ = inputs_embeds.shape
+        else:
+            raise ValueError(
+                "You have to specify either decoder_input_ids or decoder_inputs_embeds"
+            )
+
+        if self.gradient_checkpointing and self.training:
+            if use_cache:
+                logger.warning_once(
+                    "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`..."
+                )
+                use_cache = False
+
+        past_key_values_length = 0
+
+        if use_cache:
+            use_legacy_cache = not isinstance(past_key_values, Cache)
+            if use_legacy_cache:
+                past_key_values = DynamicCache.from_legacy_cache(past_key_values)
+            past_key_values_length = past_key_values.get_usable_length(seq_length)
+
+        if position_ids is None:
+            device = input_ids.device if input_ids is not None else inputs_embeds.device
+            position_ids = torch.arange(
+                past_key_values_length,
+                seq_length + past_key_values_length,
+                dtype=torch.long,
+                device=device,
+            )
+            position_ids = position_ids.unsqueeze(0).view(-1, seq_length)
+        else:
+            position_ids = position_ids.view(-1, seq_length).long()
+
+        if inputs_embeds is None:
+            inputs_embeds = self.embed_tokens(input_ids)
+
+        if (
+            attention_mask is not None
+            and self._attn_implementation == "flash_attention_2"
+            and use_cache
+        ):
+            is_padding_right = attention_mask[:, -1].sum().item() != batch_size
+            if is_padding_right:
+                raise ValueError(
+                    "You are attempting to perform batched generation with padding_side='right'"
+                    " this may lead to unexpected behaviour for Flash Attention version of Mistral. Make sure to "
+                    " call `tokenizer.padding_side  = 'left'` before tokenizing the input. "
+                )
+
+        if self._attn_implementation == "flash_attention_2":
+            # 2d mask is passed through the layers
+            attention_mask = (
+                attention_mask
+                if (attention_mask is not None and 0 in attention_mask)
+                else None
+            )
+        elif self._attn_implementation == "sdpa" and not output_attentions:
+            # The original implementation is by-passed, see attn_mask_utils.py
+            attention_mask = _prepare_4d_causal_attention_mask_for_sdpa(
+                attention_mask,
+                (batch_size, seq_length),
+                inputs_embeds,
+                past_key_values_length,
+            )
+        else:
+            # 4d mask is passed through the layers
+            attention_mask = _prepare_4d_causal_attention_mask(
+                attention_mask,
+                (batch_size, seq_length),
+                inputs_embeds,
+                past_key_values_length,
+                sliding_window=self.config.sliding_window,
+            )
+
+        hidden_states = inputs_embeds
+
+        # decoder layers
+        all_hidden_states = () if output_hidden_states else None
+        all_self_attns = () if output_attentions else None
+        next_decoder_cache = None
+
+        for decoder_layer in self.layers:
+            if output_hidden_states:
+                all_hidden_states += (hidden_states,)
+
+            if self.gradient_checkpointing and self.training:
+                layer_outputs = self._gradient_checkpointing_func(
+                    decoder_layer.__call__,
+                    hidden_states,
+                    attention_mask,
+                    position_ids,
+                    past_key_values,
+                    output_attentions,
+                    use_cache,
+                )
+            else:
+                layer_outputs = decoder_layer(
+                    hidden_states,
+                    attention_mask=attention_mask,
+                    position_ids=position_ids,
+                    past_key_value=past_key_values,
+                    output_attentions=output_attentions,
+                    use_cache=use_cache,
+                )
+
+            hidden_states = layer_outputs[0]
+
+            if use_cache:
+                next_decoder_cache = layer_outputs[2 if output_attentions else 1]
+
+            if output_attentions:
+                all_self_attns += (layer_outputs[1],)
+
+        hidden_states = self.norm(hidden_states)
+
+        # add hidden states from the last decoder layer
+        if output_hidden_states:
+            all_hidden_states += (hidden_states,)
+
+        next_cache = None
+        if use_cache:
+            next_cache = (
+                next_decoder_cache.to_legacy_cache()
+                if use_legacy_cache
+                else next_decoder_cache
+            )
+
+        if not return_dict:
+            return tuple(
+                v
+                for v in [hidden_states, next_cache, all_hidden_states, all_self_attns]
+                if v is not None
+            )
+        return BaseModelOutputWithPast(
+            last_hidden_state=hidden_states,
+            past_key_values=next_cache,
+            hidden_states=all_hidden_states,
+            attentions=all_self_attns,
+        )
+
+
+class MistralBiForMNTP(MistralForCausalLM):
+    def __init__(self, config):
+        MistralPreTrainedModel.__init__(self, config)
+        self.model = MistralBiModel(config)
+        self.vocab_size = config.vocab_size
+        self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
+
+        # Initialize weights and apply final processing
+        self.post_init()

classifier.py

@@ -0,0 +1,88 @@
+from bidirectional_mistral import MistralBiModel
+from transformers import MistralPreTrainedModel
+import torch
+import numpy as np
+from typing import Optional, List
+from torch import nn
+from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss
+from transformers.modeling_outputs import SequenceClassifierOutputWithPast
+
+
+class MistralForSequenceClassification(MistralPreTrainedModel):
+    def __init__(self, config):
+        super().__init__(config)
+        self.num_labels = config.num_labels
+        self.model = MistralBiModel(config)
+        self.score = nn.Linear(config.hidden_size, self.num_labels, bias=False)
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    def forward(
+        self,
+        input_ids: torch.LongTensor = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_values: Optional[List[torch.FloatTensor]] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+        labels: Optional[torch.LongTensor] = None,
+        use_cache: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+    ):
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
+            Labels for computing the sequence classification/regression loss. Indices should be in `[0, ...,
+            config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If
+            `config.num_labels > 1` a classification loss is computed (Cross-Entropy).
+        """
+        return_dict = return_dict if return_dict is not None else self.config.use_return_dict
+
+        transformer_outputs = self.model(
+            input_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            use_cache=use_cache,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+        )
+        pooled_output = transformer_outputs[0][:, 0]
+        logits = self.score(pooled_output)
+
+        loss = None
+        if labels is not None:
+            if self.config.problem_type is None:
+                if self.num_labels == 1:
+                    self.config.problem_type = "regression"
+                elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int):
+                    self.config.problem_type = "single_label_classification"
+                else:
+                    self.config.problem_type = "multi_label_classification"
+
+            if self.config.problem_type == "regression":
+                loss_fct = MSELoss()
+                if self.num_labels == 1:
+                    loss = loss_fct(logits.squeeze(), labels.squeeze())
+                else:
+                    loss = loss_fct(logits, labels)
+            elif self.config.problem_type == "single_label_classification":
+                loss_fct = CrossEntropyLoss()
+                loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))
+            elif self.config.problem_type == "multi_label_classification":
+                loss_fct = BCEWithLogitsLoss()
+                loss = loss_fct(logits, labels)
+        if not return_dict:
+            output = (logits,) + transformer_outputs[2:]
+            return ((loss,) + output) if loss is not None else output
+
+        return SequenceClassifierOutputWithPast(
+            loss=loss,
+            logits=logits,
+            past_key_values=transformer_outputs.past_key_values,
+            hidden_states=transformer_outputs.hidden_states,
+            attentions=transformer_outputs.attentions,
+        )