add pytorch build skill

helpers/skills/pytorch-build/SKILL.MD

@@ -0,0 +1,154 @@
+---
+description: PyTorch source build automation and debugging
+globs:
+  - pytorch/setup.py
+  - pytorch/CMakeLists.txt
+  - pytorch/build/**
+  - scripts/build_pytorch.sh
+alwaysApply: false
+---
+
+# PyTorch Build Automation
+
+## Environment
+
+| Property | Value |
+|----------|-------|
+| Workspace | `/path/to/your-container` |
+| PyTorch source | `/workspaces/pytorch-devcontainers/pytorch` |
+| Python | 3.13.9 |
+| Virtual env | `/root/.venv` |
+| CUDA | 12.8 at `/usr/local/cuda-12.8` |
+| OS | Fedora 41 (Container) |
+
+---
+
+## Workflows
+
+### When user says "build pytorch" or "build":
+
+```bash
+cd /workspaces/pytorch-devcontainers/pytorch
+BUILD_TEST=0 MAX_JOBS=$(nproc) pip install -e .
+python -c "import torch; print(f'✓ PyTorch {torch.__version__} | CUDA: {torch.cuda.is_available()}')"
+```
+
+### When user says "clean build" or "rebuild from scratch":
+
+```bash
+source /root/.venv/bin/activate
+cd /workspaces/pytorch-devcontainers/pytorch
+rm -rf build/
+python setup.py clean
+git submodule sync
+git submodule update --init --recursive --force
+BUILD_TEST=0 MAX_JOBS=$(nproc) pip install -e .
+python -c "import torch; print(f'✓ PyTorch {torch.__version__} | CUDA: {torch.cuda.is_available()}')"
+```
+
+### When user says "debug build":
+
+```bash
+source /root/.venv/bin/activate
+cd /workspaces/pytorch-devcontainers/pytorch
+DEBUG=1 BUILD_TEST=0 MAX_JOBS=$(nproc) pip install -e .
+python -c "import torch; print(f'✓ PyTorch {torch.__version__} (DEBUG) | CUDA: {torch.cuda.is_available()}')"
+```
+
+### When user says "setup.py develop" or "develop mode":
+
+```bash
+source /root/.venv/bin/activate
+cd /workspaces/pytorch-devcontainers/pytorch
+python setup.py develop
+```
+
+### When user says "verify torch" or "check install":
+
+```bash
+python -c "import torch; print(f'PyTorch {torch.__version__}'); print(f'CUDA available: {torch.cuda.is_available()}'); print(f'CUDA version: {torch.version.cuda if torch.cuda.is_available() else \"N/A\"}')"
+```
+
+---
+
+## Build Environment Variables
+
+Set these BEFORE running build commands:
+
+| Variable | Purpose | Example |
+|----------|---------|---------|
+| `MAX_JOBS` | Parallel compile jobs | `export MAX_JOBS=$(nproc)` |
+| `BUILD_TEST` | Build C++ tests (0=skip, faster) | `export BUILD_TEST=0` |
+| `DEBUG` | Debug build with symbols | `export DEBUG=1` |
+| `USE_CUDA` | Force CUDA build | `export USE_CUDA=1` |
+| `USE_CUDNN` | Enable cuDNN | `export USE_CUDNN=1` |
+| `USE_DISTRIBUTED` | Enable distributed training | `export USE_DISTRIBUTED=1` |
+| `USE_MKLDNN` | Enable oneDNN/MKL-DNN | `export USE_MKLDNN=1` |
+
+---
+
+## Common Build Errors & Fixes
+
+### `ninja: build stopped: subcommand failed`
+
+**Cause:** C++ compilation error  
+**Fix:**
+1. Scroll up in terminal to find the actual error
+2. Check `pytorch/build/CMakeFiles/CMakeError.log`
+3. Fix the C++ issue and rebuild
+
+### `undefined symbol` or `ImportError` after build
+
+**Cause:** ABI mismatch or stale build artifacts  
+**Fix:** Clean rebuild:
+```bash
+cd /workspaces/pytorch-devcontainers/pytorch
+rm -rf build/
+python setup.py clean
+pip install -e .
+```
+
+### Out of memory during compilation
+
+**Cause:** Too many parallel jobs  
+**Fix:** Reduce parallelism:
+```bash
+MAX_JOBS=4 pip install -e .
+```
+
+### Submodule errors / missing dependencies
+
+**Fix:**
+```bash
+cd /workspaces/pytorch-devcontainers/pytorch
+git submodule sync
+git submodule update --init --recursive --force
+```
+
+### `CUDA_HOME is not set`
+
+**Fix:**
+```bash
+export CUDA_HOME=/usr/local/cuda
+```
+
+### `nvcc not found`
+
+**Fix:**
+```bash
+export PATH=/usr/local/cuda-12.8/bin:$PATH
+```
+
+---
+
+## Build Logs
+
+When debugging build failures, check these files:
+
+| Log | Location |
+|-----|----------|
+| CMake errors | `pytorch/build/CMakeFiles/CMakeError.log` |
+| CMake output | `pytorch/build/CMakeFiles/CMakeOutput.log` |
+| Compile commands | `pytorch/compile_commands.json` |
+
+---

helpers/skills/pytorch-build/scripts/build_pytorch.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Activate virtual environment from /root/.venv
+source ${HOME}/.venv/bin/activate
+
+cd pytorch
+
+git submodule sync
+git submodule update --init --recursive --force
+
+uv pip install --no-build-isolation -v -e .
+
+echo "PyTorch built successfully"