This PR migrates Activated LoRA (aLoRA) support from a standalone Github (see above) to PEFT itself. Note there is also an active PR for vLLM inference support for Activated LoRA: vllm-project/vllm#19710 . There are also collections of aLoRA models on huggingface (in the ibm-granite org), note that these preexisting models run off of the standalone github repo and will be updated to work with this new PEFT feature if merged. Description of changes: Activated LoRA is a modification of the LoRA architecture to "activate" the adapter weights only on tokens coming after a specified invocation_string. This fact makes it so that KV values for the string coming before the activation matches KV values for the base model. This allows KV cache for the input to be interchangeable between the base model and adapter model, and allows for major speedups in inference pipelines (e.g. agentic pipelines) that want to use both base models and adapter models. See the paper for detailed exploration of use cases and further elaboration. Other notes: The crux of the changes are really in layer.py. Everything else is simply managing the alora_offsets quantity which defines where the weights start to be activated. This is determined by scanning input strings for the invocation_string defined in the aLoraConfig. I believe that aLoRA really only makes sense for CausalLMs, hence I've only implemented this for that model type. Merging doesn't make sense for aLoRA adapters since the weights are not universally applied to all tokens. I used the LoRA code as a starting point, but did not implement various seemingly extra features in that code. As of now, invocation_string should probably start and end with special tokens, to avoid tokenizer issues at the boundary. Open to suggestions on how to make this more general if needed. --------- Co-authored-by: githubnemo <githubnemo@users.noreply.github.com>
Generating the documentation
To generate the documentation, you first have to build it. Several packages are necessary to build the doc, you can install them with the following command, at the root of the code repository:
pip install -e ".[docs]"
Then you need to install our special tool that builds the documentation:
pip install git+https://github.com/huggingface/doc-builder
NOTE
You only need to generate the documentation to inspect it locally (if you're planning changes and want to check how they look before committing for instance). You don't have to commit to the built documentation.
Building the documentation
Once you have setup the doc-builder
and additional packages, you can generate the documentation by
typing the following command:
doc-builder build peft docs/source/ --build_dir ~/tmp/test-build
You can adapt the --build_dir
to set any temporary folder you prefer. This command will create it and generate
the MDX files that will be rendered as the documentation on the main website. You can inspect them in your favorite
Markdown editor.
Previewing the documentation
To preview the docs, first install the watchdog
module with:
pip install watchdog
Then run the following command:
doc-builder preview {package_name} {path_to_docs}
For example:
doc-builder preview peft docs/source
The docs will be viewable at http://localhost:3000. You can also preview the docs once you have opened a PR. You will see a bot add a comment to a link where the documentation with your changes lives.
NOTE
The preview
command only works with existing doc files. When you add a completely new file, you need to update _toctree.yml
& restart preview
command (ctrl-c
to stop it & call doc-builder preview ...
again).
Adding a new element to the navigation bar
Accepted files are Markdown (.md or .mdx).
Create a file with its extension and put it in the source directory. You can then link it to the toc-tree by putting
the filename without the extension in the _toctree.yml
file.
Renaming section headers and moving sections
It helps to keep the old links working when renaming the section header and/or moving sections from one document to another. This is because the old links are likely to be used in Issues, Forums, and Social media and it'd make for a much more superior user experience if users reading those months later could still easily navigate to the originally intended information.
Therefore, we simply keep a little map of moved sections at the end of the document where the original section was. The key is to preserve the original anchor.
So if you renamed a section from: "Section A" to "Section B", then you can add at the end of the file:
Sections that were moved:
[ <a href="#section-b">Section A</a><a id="section-a"></a> ]
and of course, if you moved it to another file, then:
Sections that were moved:
[ <a href="../new-file#section-b">Section A</a><a id="section-a"></a> ]
Use the relative style to link to the new file so that the versioned docs continue to work.
Writing Documentation - Specification
The huggingface/peft
documentation follows the
Google documentation style for docstrings,
although we can write them directly in Markdown.
Adding a new tutorial
Adding a new tutorial or section is done in two steps:
- Add a new file under
./source
. This file can either be ReStructuredText (.rst) or Markdown (.md). - Link that file in
./source/_toctree.yml
on the correct toc-tree.
Make sure to put your new file under the proper section. It's unlikely to go in the first section (Get Started), so depending on the intended targets (beginners, more advanced users, or researchers) it should go into sections two, three, or four.
Writing source documentation
Values that should be put in code
should either be surrounded by backticks: `like so`. Note that argument names
and objects like True, None, or any strings should usually be put in code
.
When mentioning a class, function, or method, it is recommended to use our syntax for internal links so that our tool adds a link to its documentation with this syntax: [`XXXClass`] or [`function`]. This requires the class or function to be in the main package.
If you want to create a link to some internal class or function, you need to
provide its path. For instance: [`utils.gather`]. This will be converted into a link with
utils.gather
in the description. To get rid of the path and only keep the name of the object you are
linking to in the description, add a ~: [`~utils.gather`] will generate a link with gather
in the description.
The same works for methods so you can either use [`XXXClass.method`] or [~`XXXClass.method`].
Defining arguments in a method
Arguments should be defined with the Args:
(or Arguments:
or Parameters:
) prefix, followed by a line return and
an indentation. The argument should be followed by its type, with its shape if it is a tensor, a colon, and its
description:
Args:
n_layers (`int`): The number of layers of the model.
If the description is too long to fit in one line (more than 119 characters in total), another indentation is necessary before writing the description after the argument.
Finally, to maintain uniformity if any one description is too long to fit on one line, the rest of the parameters should follow suit and have an indention before their description.
Here's an example showcasing everything so far:
Args:
gradient_accumulation_steps (`int`, *optional*, default to 1):
The number of steps that should pass before gradients are accumulated. A number > 1 should be combined with `Accelerator.accumulate`.
cpu (`bool`, *optional*):
Whether or not to force the script to execute on CPU. Will ignore GPU available if set to `True` and force the execution on one process only.
For optional arguments or arguments with defaults we follow the following syntax: imagine we have a function with the following signature:
def my_function(x: str = None, a: float = 1):
then its documentation should look like this:
Args:
x (`str`, *optional*):
This argument controls ... and has a description longer than 119 chars.
a (`float`, *optional*, defaults to 1):
This argument is used to ... and has a description longer than 119 chars.
Note that we always omit the "defaults to `None`" when None is the default for any argument. Also note that even
if the first line describing your argument type and its default gets long, you can't break it into several lines. You can
however write as many lines as you want in the indented description (see the example above with input_ids
).
Writing a multi-line code block
Multi-line code blocks can be useful for displaying examples. They are done between two lines of three backticks as usual in Markdown:
```python
# first line of code
# second line
# etc
```
Writing a return block
The return block should be introduced with the Returns:
prefix, followed by a line return and an indentation.
The first line should be the type of the return, followed by a line return. No need to indent further for the elements
building the return.
Here's an example of a single value return:
Returns:
`List[int]`: A list of integers in the range [0, 1] --- 1 for a special token, 0 for a sequence token.
Here's an example of a tuple return, comprising several objects:
Returns:
`tuple(torch.FloatTensor)` comprising various elements depending on the configuration ([`BertConfig`]) and inputs:
- ** loss** (*optional*, returned when `masked_lm_labels` is provided) `torch.FloatTensor` of shape `(1,)` --
Total loss is the sum of the masked language modeling loss and the next sequence prediction (classification) loss.
- **prediction_scores** (`torch.FloatTensor` of shape `(batch_size, sequence_length, config.vocab_size)`) --
Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
Styling the docstring
We have an automatic script running with the make style
comment that will make sure that:
- the docstrings fully take advantage of the line width
- all code examples are formatted using black, like the code of the Transformers library
This script may have some weird failures if you make a syntax mistake or if you uncover a bug. Therefore, it's
recommended to commit your changes before running make style
, so you can revert the changes done by that script
easily.
Writing documentation examples
The syntax, for example, docstrings can look as follows:
Example:
```python
>>> import time
>>> from accelerate import Accelerator
>>> accelerator = Accelerator()
>>> if accelerator.is_main_process:
... time.sleep(2)
>>> else:
... print("I'm waiting for the main process to finish its sleep...")
>>> accelerator.wait_for_everyone()
>>> # Should print on every process at the same time
>>> print("Everyone is here")
```
The docstring should give a minimal, clear example of how the respective function is to be used in inference and also include the expected (ideally sensible) output. Often, readers will try out the example before even going through the function or class definitions. Therefore, it is of utmost importance that the example works as expected.