TIM-VX/samples/nbg_runner_pybind/README.md

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# VSI NBG Runner Python Binding
This project is a python package that wraps OpenVX API using pybind11. It provides simple python API to load, query and run model NBG.
## Installation
```cmake
cmake -B build -DVIVANTE_SDK_DIR=${VIV_SDK_INSTALL_PATH}
cmake --build build
```
The built python binding lib can be found at
`build/src/_nbg_runner.cpython-{python_version}-{platform}.so`. Place the lib into `python/nbg_runner/_binding/`.
## Usage
### Tensor Info
| Field | Type | Value Sample |
|:-----------------:|:-----------------:|:-------------:|
| rank | int | 4 |
| shape | Tuple[int, ...] | (1,3,224,224) |
| dtype | str | "uint8" |
| qtype | str | "affine" |
| scale | float | 0.007874 |
| zero_point | int | 128 |
| fixed_point_pos | int | 0 |
- `shape` is in C-style row major order, which is consistent with NumPy.
### Set Environment Vars
```shell
# Set HW target If the driver is compiled with vsimulator.
VSIMULATOR_CONFIG=VIP9000ULSI_PID0XBA
# Locate the OVX driver.
VIVANTE_SDK_DIR=${VIV_SDK_INSTALL_PATH}
LD_LIBRARY_PATH=${VIVANTE_SDK_DIR}/[lib|lib64|drivers]
# Set PYTHONPATH to the dir containing nbg_runner module.
PYTHONPATH=${workspaceFolder}/python
```
### Example
See detailed examples in `examples/*.py`
```python
from nbg_runner import OVXExecutor
# Load a model NBG file.
executor = OVXExecutor("path/to/model.nbg")
# Query model I/O tensors count.
num_inputs = executor.get_num_inputs()
num_outputs = executor.get_num_outputs()
# Get I/O tensor info by index.
input_info = executor.get_input_info(0)
output_info = executor.get_output_info(0)
# Or get all I/O tensors infos at once.
input_infos = executor.get_input_infos()
output_infos = executor.get_output_infos()
# Prepare inputs.
input_tensors: List[NDArray] = ...
# Set input tensor by index.
for i, input_tensor in enumerate(input_tensors):
executor.set_input(i, input_tensor)
# Or set all input tensors at once.
executor.set_inputs(input_tensors)
# Run inference.
executor.run()
# Get output tensor by index.
for i in range(num_outputs):
output_tensor = executor.get_output(i)
# Or get all output tensors at once.
output_tensors = executor.get_outputs()
```