feature: Conversion of HSOpticalFlow Program to HIP#453
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zichguan-amd
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May 28, 2026
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Please update the root README to include Applications/optical_flow, and Applications/Makefile to include the example.
- Add #include <hip/hip_runtime.h> to derivativesKernel.hip and downscaleKernel.hip (reviewer request for self-contained headers) - Fix LoadImageAsFP32 docstring: loads RGB (3-channel), not 4-channel - Update copyright year to 2026 in CMakeLists.txt and Makefile - Add optical_flow to Applications/Makefile EXAMPLES list - Add optical_flow entry to root README.md - Remove accidental .venv/ entry from root .gitignore - Rewrite optical_flow README with accurate build/run instructions: correct CMake compiler flag (clang++ not hipcc), ROCM_PATH and LD_LIBRARY_PATH env vars, working-directory-independent run instructions Co-Authored-By: Claude Sonnet 4 <noreply@anthropic.com>
zichguan-amd
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Motivation
Closes #447
Ports the NVIDIA HSOpticalFlow CUDA sample to HIP as a new
Applications/optical_flowexample. The Horn-Schunck variational optical flow algorithm demonstrates several non-trivial HIP features (texture objects withhipResourceTypePitch2D, cooperative groups, Gaussian pyramids) that have no existing example in the repository.Technical Details
Implements the Horn-Schunck optical flow algorithm on HIP:
Downscale(4-tap filter viatex2Dbilinear fetch)iterative solver refines the flow
flowGold.cpp) runs the same algorithm on the host; the GPU and CPU results are compared via L1 norm per pixel (threshold: 0.05)FlowGPU.floandFlowCPU.floin Middlebury.floformatKey porting changes from CUDA:
helper_functions.h,sdkLoadPPM4ubstb_image.h(already in-repo)findCudaDevice(argc, argv)hipGetDeviceProperties(&props, 0)cooperative_groups.hhip/hip_cooperative_groups.hStrideAlignment = 32StrideAlignment = 64— ROCm requirespitchInBytesto be a multiple of 256 bytes forhipResourceTypePitch2DAll four texture wrappers (
downscaleKernel,upscaleKernel,warpingKernel,derivativesKernel) usehipResourceTypePitch2DwithhipAddressModeMirrorandhipFilterModeLinear, exercising the texture object API as it is typically used in production imaging workloads.Test Plan
Built and run with
makeon a ROCm-capable AMD GPU:cd Applications/optical_flow make ./optical_flowInput: two consecutive frames from the Middlebury optical flow dataset (data/frame10.ppm, data/frame11.ppm).
Test Result
HSOpticalFlow Starting...
Added/Updated documentation?
Submission Checklist