Fix ROCm torch install: use find-links, not --index-url (devcontainer, README, hip_utils)

.devcontainer/rocm/Dockerfile

@@ -80,10 +80,17 @@ RUN \
     echo 'eval "$(micromamba shell hook --shell bash)"' >> /home/$USERNAME/.bashrc && \
     echo "micromamba activate ${MAMBA_ENV_NAME}" >> /home/$USERNAME/.bashrc
 
-# Create a new micromamba env and install needed packages for flashinfer development
+# Create a new micromamba env and install needed packages for flashinfer development.
+# torch uses -f/--find-links (not --index-url) because the radeon repo is a flat
+# wheel listing, not a PEP 503 simple index — with --index-url pip requests the
+# per-package path (.../torch/), which 404s, and the install fails with "No
+# matching distribution found". After installing, assert torch is a ROCm/HIP build
+# (torch.version.hip is not None) so the build fails fast if -f ever resolves a
+# PyPI CPU/CUDA wheel instead of the radeon ROCm wheel.
 RUN /bin/micromamba create -n ${MAMBA_ENV_NAME} python=${PY_VERSION} gtest gmock bash-completion -c conda-forge && \
     /bin/micromamba run -n ${MAMBA_ENV_NAME} pip install --no-cache-dir cmake ninja "scikit-build-core>=0.4.3" "setuptools-scm>=9.2" pre-commit numpy pytest pytest-cov pytest-xdist pytest-rerunfailures pybind11 ruff && \
-    /bin/micromamba run -n ${MAMBA_ENV_NAME} pip install --no-cache-dir torch==${TORCH_VERSION} --index-url https://repo.radeon.com/rocm/manylinux/rocm-rel-${ROCM_VERSION}/ && \
+    /bin/micromamba run -n ${MAMBA_ENV_NAME} pip install --no-cache-dir torch==${TORCH_VERSION} -f https://repo.radeon.com/rocm/manylinux/rocm-rel-${ROCM_VERSION}/ && \
+    /bin/micromamba run -n ${MAMBA_ENV_NAME} python -c "import torch, sys; hip = torch.version.hip; print(f'torch {torch.__version__} (hip={hip})'); sys.exit('ERROR: installed torch has no ROCm/HIP build (hip is None)' if hip is None else 0)" && \
     /bin/micromamba run -n ${MAMBA_ENV_NAME} pip install amd_aiter==${AITER_VERSION} --extra-index-url https://pypi.amd.com/rocm-${AITER_ROCM_VERSION}/simple
 SHELL ["/usr/local/bin/_dockerfile_shell.sh"]
 

README.md

@@ -88,7 +88,7 @@ Install the matching ROCm-enabled PyTorch wheel from
 <https://repo.radeon.com>:
 
 ```bash
-pip install torch==2.9.1 --index-url https://repo.radeon.com/rocm/manylinux/rocm-rel-7.2/
+pip install torch==2.9.1 -f https://repo.radeon.com/rocm/manylinux/rocm-rel-7.2/
 ```
 
 Other versions may work but have not been tested. Replace `7.2` with the
@@ -141,11 +141,14 @@ pip install amd-flashinfer --index-url https://pypi.amd.com/simple/
 Install the matching ROCm-enabled torch package from <https://repo.radeon.com>:
 
 ```bash
-pip install torch==2.9.1 --index-url https://repo.radeon.com/rocm/manylinux/rocm-rel-7.2/
+pip install torch==2.9.1 -f https://repo.radeon.com/rocm/manylinux/rocm-rel-7.2/
 ```
 
-**NOTE:** Use `--index-url` (not `-f`) so pip cannot silently fall back
-to a CPU-only PyPI wheel.
+**NOTE:** The radeon repo is a flat wheel listing, not a PEP 503 index, so
+`--index-url` fails with "No matching distribution found" — use `-f`
+(`--find-links`). pip still prefers the ROCm wheel over a same-version PyPI
+wheel because its `+rocm<X.Y>` local version ranks higher. Confirm the result
+with `python -c "import torch; assert torch.version.hip, 'not a ROCm build'"`.
 
 ### Trying the Examples
 

flashinfer/hip_utils.py

@@ -536,7 +536,7 @@ def check_torch_rocm_compatibility() -> None:
             "  1. Uninstall current PyTorch:\n"
             "     pip uninstall torch\n\n"
             "  2. Install PyTorch for ROCm:\n"
-            "     pip install torch==2.7.1 --index-url https://repo.radeon.com/rocm/manylinux/rocm-rel-6.4/\n\n"
+            "     pip install torch==2.7.1 -f https://repo.radeon.com/rocm/manylinux/rocm-rel-6.4/\n\n"
             "See https://github.com/rocm/flashinfer for detailed installation instructions.\n"
             + "="
             * 70
@@ -559,11 +559,11 @@ def check_torch_rocm_compatibility() -> None:
                 f"  PyTorch ROCm version: {torch_rocm_major_minor}\n\n"
                 f"This may cause runtime errors or crashes.\n\n"
                 f"To fix, reinstall PyTorch for your ROCm version:\n"
-                f"  pip install torch==2.7.1 --index-url "
+                f"  pip install torch==2.7.1 -f "
                 f"https://repo.radeon.com/rocm/manylinux/rocm-rel-{system_rocm}/\n\n"
                 f"Or if using uv:\n"
                 f"  export FLASHINFER_ROCM_VERSION={system_rocm}\n"
-                f"  uv pip install torch==2.7.1 --index-url "
+                f"  uv pip install torch==2.7.1 -f "
                 f"https://repo.radeon.com/rocm/manylinux/rocm-rel-{system_rocm}/\n"
                 f"{'=' * 70}",
                 RuntimeWarning,