Files
axolotl/examples/archived/xgen-7b/xgen-7b-8k-qlora.yml
Wing Lian e4032fc90f Refactor separate attention flags with attn_implementation and capability/concerns feature flags (#3602)
* upgrade to torchao 0.17.0

* chore: lint

* refactor attention handling

* replace legacy attention boolean flags with capability properties

Replace checks with capability-based properties derived from attn_implementation

This separates three concerns that were conflated under flash_attention:
1. Backend selection -> attn_implementation enum
2. Packing capability -> attn_supports_packing property
3. Flash-attn library dependency -> attn_uses_flash_lib property

* compute attn capability flags in normalizer instead of properties

* make attn_implementation the single source of truth

* move attention-dependent validators to mode=after

* migrate remaining consumers to canonical attn_implementation

* expand attention tests + rewrite docs

* migrate example configs to canonical attn_implementation

* update doc snippets + reject gemma4-hybrid with non-FA2 backend

* remove dead gemma4 branch in _set_attention_config

* fix duplicate attn_implementation in gpt-oss yamls and flaky caplog tests

* drop "Phase 2" naming from attn-implementation tests

* regroup attn_implementation tests by feature concern

* clean up verbose comments and remove MD

Signed-off-by: Wing Lian <wing@axolotl.ai>
Co-authored-by: Axolotl Swarm <no-reply@axolotl.ai>

* fix(collator): pass return_dict=True at apply_chat_template top level for transformers 5.x

In transformers 5.x, ProcessorMixin.apply_chat_template gained its own
`return_dict` parameter (defaulting to False).  When return_dict=False
and tokenize=True the method returns out["input_ids"] directly — a 2-D
tensor — rather than the full BatchFeature dict.

The old code placed `return_dict=True` inside processor_kwargs.  In
transformers 5.x those kwargs are forwarded to the underlying processor
call self(...) where _merge_kwargs silently ignores any key not present
in MllamaProcessorKwargs (emitting a warning).  The outer return_dict
therefore stayed False, apply_chat_template returned the raw input_ids
tensor, and the subsequent `batch["input_ids"]` attempted to index a
2-D tensor with the 9-character string "input_ids", producing:

  IndexError: too many indices for tensor of dimension 2

The fix is to pass return_dict=True as a top-level keyword argument to
apply_chat_template (where it is actually consumed) and remove it from
processor_kwargs (where it was silently dropped).  No version guard is
needed: transformers is pinned to ==5.5.4 in pyproject.toml.

Adds a unit-level regression test (tests/test_mm_chat_collator.py) that
mocks the processor to return a raw tensor when apply_chat_template is
called without top-level return_dict=True, verifying the four invariants:
process_rows returns a dict, input_ids is 2-D, labels is 2-D, and
apply_chat_template receives return_dict=True as a top-level kwarg.

Fixes: tests/e2e/test_llama_vision.py::TestLlamaVision::test_lora_llama_vision_multimodal_dataset
Fixes: tests/e2e/test_llama_vision.py::TestLlamaVision::test_lora_llama_vision_text_only_dataset
Signed-off-by: Wing Lian <wing@axolotl.ai>
Co-authored-by: Axolotl Swarm <no-reply@axolotl.ai>

* fix(collator): process_rows returns dict (BatchFeature) shape

Two related changes for the multimodal chat collator under transformers 5.x:

1. Wrap apply_chat_template result in dict(...) so process_rows returns
   a plain dict rather than a BatchFeature instance. BatchFeature is a
   Mapping but not a dict; downstream code that did
     batch["labels"] = self.processing_strategy.process_labels(batch["input_ids"])
   would index on a tensor when the result wasn't dict-shaped, raising
     IndexError: too many indices for tensor of dimension 2

2. Soften the regression test's contract from `dict` to `Mapping` so it
   exercises the actual semantic guarantee (key/value access) rather
   than the implementation detail (dict vs BatchFeature). Test guards
   against the original transformers 5.x breakage where apply_chat_template's
   return_dict default went from True to False.

Includes regression test under tests/test_mm_chat_collator.py.

Bug surfaced via swarm dispatch task_01KQHPNAYD8XARSNSDJVW1GPF6 against
attn-implementation-refactor; squash-merged from agent commits 4de886fd
+ dc9fcf4f.

Signed-off-by: Wing Lian <wing@axolotl.ai>

---------

Signed-off-by: Wing Lian <wing@axolotl.ai>
Co-authored-by: Axolotl Swarm <no-reply@axolotl.ai>
2026-05-05 10:15:18 -04:00

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YAML

# An example finetuning Saleforce's XGen-7b model with 8k context using qlora
# on Tim Dettmer's Guanaco dataset.
base_model: Salesforce/xgen-7b-8k-base
# optionally might have model_type or tokenizer_type
model_type: AutoModelForCausalLM
tokenizer_type: AutoTokenizer
# Automatically upload checkpoint and final model to HF
# hub_model_id: username/custom_model_name
trust_remote_code: true
load_in_8bit: false
# enable 4bit for QLoRA
load_in_4bit: true
gptq: false
push_dataset_to_hub:
datasets:
- path: timdettmers/openassistant-guanaco
data_files:
- openassistant_best_replies_train.jsonl
type: "completion"
dataset_prepared_path:
val_set_size: 0.05
# enable QLoRA
adapter: qlora
lora_model_dir:
sequence_len: 8192
max_packed_sequence_len:
# hyperparameters from QLoRA paper Appendix B.2
# "We find hyperparameters to be largely robust across datasets"
lora_r: 64
lora_alpha: 16
# 0.1 for models up to 13B
# 0.05 for 33B and 65B models
lora_dropout: 0.05
# add LoRA modules on all linear layers of the base model
lora_target_linear: true
wandb_project:
wandb_entity:
wandb_watch:
wandb_name:
wandb_log_model:
output_dir: ./outputs/qlora-out
# QLoRA paper Table 9
# - 16 for 7b & 13b
# - 32 for 33b, 64 for 64b
# Max size tested on A6000
# - 7b: 40
# - 40b: 4
# decrease if OOM, increase for max VRAM utilization
micro_batch_size: 1
gradient_accumulation_steps: 1
num_epochs: 4
# Optimizer for QLoRA
optimizer: paged_adamw_32bit
torchdistx_path:
lr_scheduler: cosine
# QLoRA paper Table 9
# - 2e-4 for 7b & 13b
# - 1e-4 for 33b & 64b
learning_rate: 0.00002
bf16: auto
tf32: false
gradient_checkpointing: true
# stop training after this many evaluation losses have increased in a row
# https://huggingface.co/transformers/v4.2.2/_modules/transformers/trainer_callback.html#EarlyStoppingCallback
early_stopping_patience: 3
resume_from_checkpoint:
auto_resume_from_checkpoints: true
logging_steps: 1
attn_implementation: xformers
gptq_groupsize:
gptq_model_v1:
warmup_ratio: 0.1
evals_per_epoch: 4
saves_per_epoch: 1
weight_decay: 0.0
special_tokens:
eos_token: "<|endoftext|>"
bos_token: "<|endoftext|>"
unk_token: "<|endoftext|>"
pad_token: "<|endoftext|>"