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composable_kernel/example/40_conv2d_fwd_quantization/README.md
2025-10-16 10:13:27 +00:00

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# 2D Convolution Forward with Quantization
## Theory
This example demonstrates **2D convolution forward with quantized weights or activations**. Quantization is used to reduce memory and computation by representing values with lower-precision integer types (e.g., int8), enabling efficient inference in deep learning.
**Mathematical Formulation:**
- Quantized convolution: $Y = \text{dequant}(X_q) * \text{dequant}(W_q)$
- $X_q$, $W_q$: quantized input and weight tensors (e.g., int8)
- $\text{dequant}(x_q) = (x_q - z) \cdot s$ (scale $s$, zero-point $z$)
- $Y$: output tensor (often in higher precision, e.g., float32 or float16)
**Algorithmic Background:**
- Quantized values are dequantized on-the-fly during convolution.
- Accumulation is performed in higher precision for accuracy.
- Supports symmetric and asymmetric quantization.
- Convolution is implemented as implicit GEMM for efficiency.
## How to Run
### Prerequisites
Please follow the instructions in the main [Build Guide](../../README.md#building-ck) section as a prerequisite to building and running this example.
### Build and run
```bash
cd composable_kernel/example/40_conv2d_fwd_quantization
mkdir build && cd build
cmake -DCMAKE_CXX_COMPILER=/opt/rocm/bin/hipcc ..
make -j
# Example run
./conv2d_fwd_quantization_xdl --verify=1 --time=1
```
## Source Code Structure
### Directory Layout
```
example/40_conv2d_fwd_quantization/
├── conv2d_fwd_quantization_xdl.cpp # Main example: sets up, runs, and verifies quantized conv2d
include/ck/tensor_operation/gpu/device/
│ └── device_conv2d_fwd_quantization.hpp # Device-level quantized conv2d API
include/ck/tensor_operation/gpu/device/impl/
│ └── device_conv2d_fwd_quantization_impl.hpp # Implementation
include/ck/tensor_operation/gpu/grid/
│ └── gridwise_conv2d_fwd_quantization.hpp # Grid-level quantized conv2d kernel
include/ck/tensor_operation/gpu/element/
└── quantization_operations.hpp # Quantization/dequantization utilities
```
### Key Classes and Functions
- **DeviceConv2dFwdQuantization** (in `device_conv2d_fwd_quantization.hpp`):
Device API for quantized 2D convolution.
- **gridwise_conv2d_fwd_quantization** (in `gridwise_conv2d_fwd_quantization.hpp`):
Implements the tiled/blocking quantized conv2d kernel.
- **quantization_operations** (in `quantization_operations.hpp`):
Defines quantization and dequantization functions.
This example demonstrates how Composable Kernel supports efficient quantized convolution for deep learning inference.