Export ROCm/rocm-libraries@2d4a3223cb

example/ck_tile/06_permute/README.md

@@ -0,0 +1,94 @@
+# Permute with CK Tile
+
+This example demonstrates generic tensor permutation which is similiar to [torch.permute](https://pytorch.org/docs/stable/generated/torch.permute.html) (combined with [torch.contiguous](https://pytorch.org/docs/stable/generated/torch.Tensor.contiguous.html)). Currently we implement a generic permute kernel that support up to rank 8 arbitrary permutation with a single kernel instance. Performance is not the first consideration, we prefer a simple and general kernel implementation using `ck_tile` in this example.
+
+
+---
+
+## Algorithm and Math
+
+Given a tensor $X$ of shape $[d_0, d_1, ..., d_{n-1}]$ and a permutation $\pi$, compute:
+$$
+Y_{i_0, i_1, ..., i_{n-1}} = X_{i_{\pi(0)}, i_{\pi(1)}, ..., i_{\pi(n-1)}}
+$$
+
+- **Tilewise Permute**: Each thread block processes a tile (block) of the input, computes the permuted indices, and writes to the output.
+
+---
+
+## Tile Programming Model
+
+- **Tiles**: Each thread block processes a tile of the input tensor.
+- **Alternative Implementation**: For rank-7 tensors, a swizzled layout is supported for matrix core-friendly data loading.
+
+---
+
+## Build & Run
+
+### Arguments
+```
+args:
+          -v    weather do CPU validation or not (default:1)
+       -prec    data type. fp16/bf16/fp32 (default:fp16)
+      -shape    the shape of the input tensor (default:2,3,4)
+       -perm    permute perm (default:2,1,0)
+```
+```
+# in the root of ck_tile
+mkdir build && cd build
+../script/cmake-ck-dev.sh  ../ <arch>  # you can replace this <arch> to gfx90a, gfx942...
+make tile_example_permute -j
+```
+
+This will result in an executable `build/bin/tile_example_permute`
+
+
+### Further Examples
+
+```
+# torch
+x=torch.randn(2,3,4,6)
+y=x.permute(0,3,2,1).contiguous()
+
+# ck_tile
+./build/bin/tile_example_permute -shape=2,3,4,6 -perm=0,3,2,1
+```
+
+You can try the smoke_test:
+
+```
+# in the root of ck_tile, after you build this example
+sh example/ck_tile/06_permute/script/smoke_test.sh
+```
+
+### Alternative Implementation
+
+We have an alternative implementation under `alternative_impl/` folder, that can swizzle the tensor to be more friendly for data loading for matrix core layout. This can be enabled when dealing with a `rank-7` tensor, with a fixed pattern of either `0,1,4,2,5,3,6` or `0,1,2,4,5,3,6`. There are other shape limitation of this implementation, check the source code of `permute.cpp` for detail.
+
+```
+# example
+./build/bin/tile_example_permute -shape=3,6,4,32,16,2,8 -perm=0,1,4,2,5,3,6 # b_n0_k0_n1_k1_n2_k2
+./build/bin/tile_example_permute -shape=3,8,4,16,16,4,8 -perm=0,1,2,4,5,3,6 # b_n0_n1_k0_k1_n2_k2
+```
+
+---
+
+## Source Structure
+
+- **Kernel**: `permute.hpp` (tile-programming kernel template)
+- **Executable**: `permute.cpp` (argument parsing, kernel launch)
+- **Alternative**: `alternative_impl/` (swizzled layout for rank-7 tensors)
+- **Build**: `CMakeLists.txt`, `script/`
+
+---
+
+## Related CK Tile Examples
+
+- [03_gemm](../03_gemm/README.md): GEMM with tiles
+- [05_reduce](../05_reduce/README.md): Reductions with tiles
+- [35_batched_transpose](../35_batched_transpose/README.md): Batched transpose with tiles
+
+For distribution, `include/ck_tile/tile_program/tile_distribution/`.
+
+---
+[Back to CK Tile Examples](../README.md)