diff --git a/src/ctx_to_lora/trainer.py b/src/ctx_to_lora/trainer.py index 6d844c4..bf1b51b 100644 --- a/src/ctx_to_lora/trainer.py +++ b/src/ctx_to_lora/trainer.py @@ -13,14 +13,10 @@ from ctx_to_lora.modeling.hypernet import ModulatedPretrainedModel logger = logging.getLogger() -class DistillationTrainer(Trainer): - def __init__(self, *args, **kwargs): - self.gen_lora_l1_reg_coef = kwargs.pop("gen_lora_l1_reg_coef", 0.0) - self.use_per_ctx_average_loss = kwargs.pop("use_per_ctx_average_loss", False) - super().__init__(*args, **kwargs) - +class ModulatedModelTrainer(Trainer): # modified from the base Trainer to support per-context average loss - def get_batch_samples_ctx(self, epoch_iterator, num_batches, device): + def get_batch_samples(self, epoch_iterator, num_batches, device): + # only used with `use_per_ctx_average_loss=True` batch_samples = [] num_items_in_batch = None @@ -33,27 +29,17 @@ class DistillationTrainer(Trainer): count_num_items_in_batch = ( len(batch_samples) > 0 and "labels" in batch_samples[0] - and "ctx_ids" in batch_samples[0] - and ( - # num_items_in_batch is passed to model forward - # https://github.com/huggingface/transformers/blob/v4.49.0/src/transformers/trainer.py#L3757 - self.model_accepts_loss_kwargs - # num_items_in_batch is passed to compute_loss_func - # https://github.com/huggingface/transformers/blob/v4.49.0/src/transformers/trainer.py#L3773 - or self.compute_loss_func is not None - # num_items_in_batch is also verified if (self.model_accepts_loss_kwargs or self.compute_loss_func) - # https://github.com/huggingface/transformers/blob/v4.49.0/src/transformers/trainer.py#L3790 - ) + and "n_ctx_chunks" in batch_samples[0] ) if count_num_items_in_batch: - # For now we don't support object detection - try: - num_items_in_batch = sum( - [(batch["ctx_position_ids"] == 0).sum() for batch in batch_samples] - ) - except (TypeError, AttributeError): - pass + num_items_in_batch = dict() + num_items_in_batch["ctx"] = torch.tensor( + sum([batch["n_ctx_chunks"].numel() for batch in batch_samples]) + ) + num_items_in_batch["labels"] = sum( + [(batch["labels"].ne(-100)).sum() for batch in batch_samples] + ) if num_items_in_batch is not None: if self.args.average_tokens_across_devices: @@ -68,117 +54,138 @@ class DistillationTrainer(Trainer): return batch_samples, num_items_in_batch + +class DistillationTrainer(ModulatedModelTrainer): + def __init__(self, *args, **kwargs): + self.gen_lora_l1_reg_coef = kwargs.pop("gen_lora_l1_reg_coef", 0.0) + self.use_per_ctx_average_loss = kwargs.pop("use_per_ctx_average_loss", False) + super().__init__(*args, **kwargs) + def compute_loss( self, model, inputs, return_outputs=False, num_items_in_batch=None ): - if self.model_accepts_loss_kwargs: - loss_kwargs = {} - if num_items_in_batch is not None: - loss_kwargs["num_items_in_batch"] = num_items_in_batch - inputs = {**inputs, **loss_kwargs} - use_kl = "logprobs_vals" in inputs - if use_kl: - labels = inputs.pop("labels", None) - label_pos = torch.where(labels != -100) + # NOTE: the loss output from this fn will be ***added*** + # meaning that we should always scale the loss wrt `num_items_in_batch` + # (average over the number of items in the accumulated batch) + + labels = inputs.pop("labels", None) + label_pos = torch.where(labels != -100) outputs, (gen_loras, _) = model(**inputs, return_generated_lora=True) - if not use_kl: - loss = outputs["loss"] + target_logp = inputs.pop("logprobs_vals").squeeze(0) + indices = inputs.pop("logprobs_indices").squeeze(0) - else: - target_logp = inputs.pop("logprobs_vals").squeeze(0) - indices = inputs.pop("logprobs_indices").squeeze(0) + assert label_pos[0].shape[0] == target_logp.shape[0], ( + "Label positions and target log probabilities should have the same # tokens." + f"Got : {label_pos[0].shape[0]=} and {target_logp.shape[0]=}" + ) - assert label_pos[0].shape[0] == target_logp.shape[0], ( - "Label positions and target log probabilities should have the same # tokens." - f"Got : {label_pos[0].shape[0]=} and {target_logp.shape[0]=}" + ##### KL loss + outputs_logits = outputs.logits[label_pos[0], label_pos[1] - 1] # shift back 1 + + teacher_logp = torch.full_like(outputs_logits, -torch.inf) + teacher_logp.scatter_(1, indices, target_logp) + # reduction = "batchmean" if num_items_in_batch is None else "sum" + + p = teacher_logp.exp() + logq = nn.functional.log_softmax(outputs_logits, dim=-1) + loss = -torch.sum(p * logq, dim=-1) + + if self.use_per_ctx_average_loss: + n_queries_per_ctx = inputs["n_queries"].tolist() + + position_ids = inputs["position_ids"].squeeze(0) + # account only label positions + label_mask = labels.squeeze(0) != -100 + label_pos_ids = label_mask * position_ids + label_pos_ids_diff = label_pos_ids.diff( + append=torch.tensor([0], device=position_ids.device) + ) + start_label_pos = torch.where((label_pos_ids_diff > 0) * ~label_mask)[0] + end_label_pos = torch.where((label_pos_ids_diff < 0) * label_mask)[0] + + label_seq_lens = end_label_pos - start_label_pos + cu_label_seq_lens = torch.cumsum(label_seq_lens, dim=0) + start_indices = torch.cat( + ( + torch.tensor([0], device=cu_label_seq_lens.device), + cu_label_seq_lens[:-1], + ) ) - ##### KL loss - outputs_logits = outputs.logits[ - label_pos[0], label_pos[1] - 1 - ] # shift back 1 - - teacher_logp = torch.full_like(outputs_logits, -torch.inf) - teacher_logp.scatter_(1, indices, target_logp) - reduction = "batchmean" if num_items_in_batch is None else "sum" - - p = teacher_logp.exp() - logq = nn.functional.log_softmax(outputs_logits, dim=-1) - loss = -torch.sum(p * logq, dim=-1) - - if self.use_per_ctx_average_loss: - n_queries_per_ctx = inputs["n_queries"].tolist() - - position_ids = inputs["position_ids"].squeeze(0) - # account only label positions - label_mask = labels.squeeze(0) != -100 - label_pos_ids = label_mask * position_ids - label_pos_ids_diff = label_pos_ids.diff( - append=torch.tensor([0], device=position_ids.device) - ) - start_label_pos = torch.where((label_pos_ids_diff > 0) * ~label_mask)[0] - end_label_pos = torch.where((label_pos_ids_diff < 0) * label_mask)[0] - - label_seq_lens = end_label_pos - start_label_pos - cu_label_seq_lens = torch.cumsum(label_seq_lens, dim=0) - start_indices = torch.cat( - ( - torch.tensor([0], device=cu_label_seq_lens.device), - cu_label_seq_lens[:-1], - ) - ) - - # these stack and split can be optimized but let's keep it simple - # mean across tokens of each q - qa_losses = torch.stack( - [ - loss[start:end].mean() - for start, end in zip(start_indices, cu_label_seq_lens) - ] - ) - - # mean across queries of each ctx - per_ctx_losses = [ - ctx.mean() for ctx in torch.split(qa_losses, n_queries_per_ctx) + # these stack and split can be optimized but let's keep it simple + # mean across tokens of each q + qa_losses = torch.stack( + [ + loss[start:end].mean() + for start, end in zip(start_indices, cu_label_seq_lens) ] + ) - # mean across contexts - loss = torch.stack(per_ctx_losses) + # mean across queries of each ctx + per_ctx_losses = [ + ctx.mean() for ctx in torch.split(qa_losses, n_queries_per_ctx) + ] - if reduction == "batchmean": - loss = loss.mean() - elif reduction == "sum" and num_items_in_batch is not None: - loss = loss.sum() / num_items_in_batch - ##### + # mean across contexts + loss = torch.stack(per_ctx_losses) + + if num_items_in_batch is not None: + if self.use_per_ctx_average_loss: + loss = loss.sum() / num_items_in_batch["ctx"] + else: + loss = loss.sum() / num_items_in_batch["labels"] + else: + # eval + loss = loss.mean() + + # if reduction == "batchmean": + # loss = loss.mean() + # elif reduction == "sum": + # # loss does not scale with grad acc + # # num_items_in_batch does + # # this works for both token-avg and ctx-avg + # # loss = loss.sum() / num_items_in_batch + + # `num_items_in_batch` is # tokens if `args.use_ctx_average_loss=False`` + # loss = loss.sum() / num_items_in_batch + ##### ##### unpack gen lora dict and compute regularization loss l1_norm = 0 n_modules = len(gen_loras) for module, lora in gen_loras.items(): - l1_norm += lora["A"].abs().mean() + lora["B"].abs().mean() + l1_norm += lora["A"].abs().sum(0).mean() + lora["B"].abs().sum(0).mean() l1_norm /= n_modules + if num_items_in_batch is not None: + # during eval `num_items_in_batch` will be None + l1_norm /= num_items_in_batch["ctx"] + + total_loss = loss + self.gen_lora_l1_reg_coef * l1_norm + ##### + + scaler = self.args.gradient_accumulation_steps + if self.args.average_tokens_across_devices and num_items_in_batch is not None: + total_loss *= self.accelerator.num_processes + scaler *= self.accelerator.num_processes + # rough estimate of the losses (we only log the values from one step) if (self.state.global_step == 1 and self.args.logging_first_step) or ( self.args.logging_strategy == IntervalStrategy.STEPS and self.state.global_step % self.state.logging_steps == 0 ): - loss_field = "kl_loss" if use_kl else "ce_loss" - self.log({loss_field: loss.item(), "gen_lora_l1_norm": l1_norm.item()}) - loss += self.gen_lora_l1_reg_coef * l1_norm - ##### + # compensate `num_items_in_batch` division + self.log( + { + "kl_loss": loss.item() * scaler, + "gen_lora_l1_norm": l1_norm.item() * scaler, + } + ) - if ( - self.args.average_tokens_across_devices - and self.model_accepts_loss_kwargs - and num_items_in_batch is not None - ): - loss *= self.accelerator.num_processes - - return (loss, outputs) if return_outputs else loss + return (total_loss, outputs) if return_outputs else total_loss -class ModulatedModelTrainer(Trainer): +class CrossEntropyTrainer(ModulatedModelTrainer): def __init__(self, *args, **kwargs): self.gen_lora_l1_reg_coef = kwargs.pop("gen_lora_l1_reg_coef", 0.0) super().__init__(*args, **kwargs) @@ -197,11 +204,11 @@ class ModulatedModelTrainer(Trainer): labels = inputs.pop("labels") else: labels = None - if self.model_accepts_loss_kwargs: - loss_kwargs = {} - if num_items_in_batch is not None: - loss_kwargs["num_items_in_batch"] = num_items_in_batch - inputs = {**inputs, **loss_kwargs} + + loss_kwargs = {} + if num_items_in_batch is not None: + loss_kwargs["num_items_in_batch"] = num_items_in_batch["labels"] + inputs = {**inputs, **loss_kwargs} outputs, (gen_loras, _) = model(**inputs, return_generated_lora=True) # Save past state if it exists if self.args.past_index >= 0: @@ -216,7 +223,7 @@ class ModulatedModelTrainer(Trainer): # User-defined compute_loss function if self.compute_loss_func is not None: loss = self.compute_loss_func( - outputs, labels, num_items_in_batch=num_items_in_batch + outputs, labels, num_items_in_batch=num_items_in_batch["labels"] ) elif model_name in MODEL_FOR_CAUSAL_LM_MAPPING_NAMES.values(): loss = self.label_smoother(outputs, labels, shift_labels=True) @@ -236,25 +243,36 @@ class ModulatedModelTrainer(Trainer): ##### unpack gen lora dict and compute regularization loss l1_norm = 0 + n_modules = len(gen_loras) for module, lora in gen_loras.items(): - l1_norm += lora["A"].abs().mean() + lora["B"].abs().mean() + l1_norm += lora["A"].abs().sum(0).mean() + lora["B"].abs().sum(0).mean() + l1_norm /= n_modules + if num_items_in_batch is not None: + # during eval `num_items_in_batch` will be None + l1_norm /= num_items_in_batch["ctx"] + + total_loss = loss + self.gen_lora_l1_reg_coef * l1_norm + ##### + + scaler = self.args.gradient_accumulation_steps + if self.args.average_tokens_across_devices and num_items_in_batch is not None: + total_loss *= self.accelerator.num_processes + scaler *= self.accelerator.num_processes + # rough estimate of the losses (we only log the values from one step) if (self.state.global_step == 1 and self.args.logging_first_step) or ( self.args.logging_strategy == IntervalStrategy.STEPS and self.state.global_step % self.state.logging_steps == 0 ): - self.log({"ce_loss": loss.item(), "gen_lora_l1_norm": l1_norm.item()}) - loss += self.gen_lora_l1_reg_coef * l1_norm - ##### + # compensate `num_items_in_batch` division + self.log( + { + "ce_loss": loss.item() * scaler, + "gen_lora_l1_norm": l1_norm.item() * scaler, + } + ) - if ( - self.args.average_tokens_across_devices - and self.model_accepts_loss_kwargs - and num_items_in_batch is not None - ): - loss *= self.accelerator.num_processes - - return (loss, outputs) if return_outputs else loss + return (total_loss, outputs) if return_outputs else total_loss def get_decay_parameter_names(model) -> list[str]: @@ -269,7 +287,7 @@ def get_decay_parameter_names(model) -> list[str]: decay_parameters = get_parameter_names( model, [nn.Embedding, nn.LayerNorm], - ["bias", "layernorm", "rmsnorm", "latents_q"], + ["scaler", "bias", "layernorm", "rmsnorm", "latents_q"], ) return decay_parameters @@ -299,8 +317,8 @@ def train_model( is_modulated_model = isinstance(model, ModulatedPretrainedModel) trainer_cls = Trainer if is_modulated_model: - logger.info("Training with modulated model. Using ModulatedModelTrainer.") - trainer_cls = ModulatedModelTrainer + logger.info("Training with modulated model. Using CrossEntropyTrainer.") + trainer_cls = CrossEntropyTrainer trainer_kwargs["gen_lora_l1_reg_coef"] = training_args.gen_lora_l1_reg_coef del training_args.gen_lora_l1_reg_coef @@ -319,8 +337,8 @@ def train_model( training_args.per_device_train_batch_size = 128 trainer = trainer_cls(**trainer_kwargs) - if getattr(trainer, "use_per_ctx_average_loss", False): - trainer.get_batch_samples = trainer.get_batch_samples_ctx + # if getattr(trainer, "use_per_ctx_average_loss", False): + # trainer.get_batch_samples = trainer.get_batch_samples_ctx # MONKEY PATCH: remove embedding layers from weight decay trainer.get_decay_parameter_names = get_decay_parameter_names