# Flan-t5

In this directory, you will find examples on how you could apply BigDL-LLM INT4 optimizations on Flan-t5 models. For illustration purposes, we utilize the [google/flan-t5-xxl](https://huggingface.co/google/flan-t5-xxl) as a reference Flan-t5 model.

## 0. Requirements
To run these examples with BigDL-LLM, we have some recommended requirements for your machine, please refer to [here](../README.md#recommended-requirements) for more information.

## Example: Predict Tokens using `generate()` API
In the example [generate.py](./generate.py), we show a basic use case for a Flan-t5 model to predict the next N tokens using `generate()` API, with BigDL-LLM INT4 optimizations.
### 1. Install
We suggest using conda to manage the Python environment. For more information about conda installation, please refer to [here](https://docs.conda.io/en/latest/miniconda.html#).

After installing conda, create a Python environment for BigDL-LLM:
```bash
conda create -n llm python=3.9 # recommend to use Python 3.9
conda activate llm

pip install --pre --upgrade bigdl-llm[all] # install the latest bigdl-llm nightly build with 'all' option
```

### 2. Run
After setting up the Python environment, you could run the example by following steps.

> **Note**: When loading the model in 4-bit, BigDL-LLM converts linear layers in the model into INT4 format. In theory, a *X*B model saved in 16-bit will requires approximately 2*X* GB of memory for loading, and ~0.5*X* GB memory for further inference.
>
> Please select the appropriate size of the Flan-t5 model based on the capabilities of your machine.

#### 2.1 Client
On client Windows machines, it is recommended to run directly with full utilization of all cores:
```powershell
python ./generate.py --prompt 'Translate to German: My name is Arthur'
```
More information about arguments can be found in [Arguments Info](#23-arguments-info) section. The expected output can be found in [Sample Output](#24-sample-output) section.

#### 2.2 Server
For optimal performance on server, it is recommended to set several environment variables (refer to [here](../README.md#best-known-configuration-on-linux) for more information), and run the example with all the physical cores of a single socket.

E.g. on Linux,
```bash
# set BigDL-Nano env variables
source bigdl-nano-init

# e.g. for a server with 48 cores per socket
export OMP_NUM_THREADS=48
numactl -C 0-47 -m 0 python ./generate.py --prompt 'Translate to German: My name is Arthur'
```
More information about arguments can be found in [Arguments Info](#23-arguments-info) section. The expected output can be found in [Sample Output](#24-sample-output) section.

#### 2.3 Arguments Info
In the example, several arguments can be passed to satisfy your requirements:

- `--repo-id-or-model-path REPO_ID_OR_MODEL_PATH`: argument defining the huggingface repo id for the Flan-t5 model (e.g. `google/flan-t5-xxl`) to be downloaded, or the path to the huggingface checkpoint folder. It is default to be `'google/flan-t5-xxl'`.
- `--prompt PROMPT`: argument defining the prompt to be infered (with integrated prompt format for chat). It is default to be `'Translate to German: My name is Arthur'`.
- `--n-predict N_PREDICT`: argument defining the max number of tokens to predict. It is default to be `32`.


#### 2.4 Sample Output
#### [google/flan-t5-xxl](https://huggingface.co/google/flan-t5-xxl)

```log
Inference time: xxxx s
-------------------- Prompt --------------------
<|User|>:Translate to German: My name is Arthur
-------------------- Output --------------------
Ich bin Arthur.
```
