optirs-gpu 0.2.0

OptiRS GPU acceleration and multi-GPU optimization
Documentation
# OptiRS GPU TODO (v0.2.0)

## Module Status: Production Ready

**Release Date**: 2025-12-30
**Tests**: 104 tests passing (1 ignored)
**Backends**: CUDA, Metal, OpenCL, WebGPU
**SciRS2 Compliance**: 100%

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## Completed: SciRS2 Integration

- [x] **Full SciRS2-Core Integration** - 100% complete
- [x] **GPU Abstractions** - Built on scirs2_core::gpu foundation
- [x] **Array Operations** - All GPU arrays use scirs2_core::array_protocol::GPUArray
- [x] **Memory Management** - Integrated with scirs2_core::memory::TrackedGpuBuffer
- [x] **Tensor Cores** - Using scirs2_core::tensor_cores for mixed precision
- [x] **Template System** - GPU kernel templates for all optimizers

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## Completed: GPU Infrastructure

### Core GPU Framework
- [x] GpuOptimizer wrapper with SciRS2 integration
- [x] GPU context management and initialization
- [x] GPU configuration with tensor cores support
- [x] Mixed-precision training support
- [x] GpuMemoryStats for memory tracking
- [x] Host-device data transfer utilities (to_gpu, from_gpu)
- [x] 11 GPU integration tests passing

### Multi-Backend Support
- [x] **CUDA Backend** (via scirs2_core::gpu)
  - [x] CUDA runtime integration
  - [x] Kernel compilation and caching
  - [x] Memory management via TrackedGpuBuffer
  - [x] Stream management with AsyncArray
  - [x] Multi-GPU support foundation

- [x] **Metal Backend** (via scirs2_core::gpu)
  - [x] Metal device setup
  - [x] MPS integration through tensor_cores
  - [x] MSL compilation
  - [x] Unified memory support
  - [x] Apple Silicon optimization

- [x] **OpenCL Backend** (via scirs2_core::gpu)
  - [x] OpenCL context management
  - [x] Kernel compilation
  - [x] Buffer management
  - [x] Vendor optimizations
  - [x] Extension detection

- [x] **WebGPU Backend** (via scirs2_core::gpu)
  - [x] WGPU device selection
  - [x] Compute shader compilation
  - [x] Buffer management with GPUArray
  - [x] WebAssembly compatibility
  - [x] Cross-platform compilation

### Memory Management
- [x] Memory pool implementation
- [x] CPU-GPU data transfer optimization
- [x] Memory alignment and padding
- [x] Memory usage tracking and profiling
- [x] Out-of-memory handling

### Optimization Kernels
- [x] SGD kernel with momentum and weight decay
- [x] Adam/AdamW kernels with numerical stability
- [x] RMSprop kernel implementation
- [x] Gradient clipping kernels
- [x] Learning rate scheduling kernels
- [x] Batch processing optimization

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## Completed: Advanced Features

### Tensor Core Acceleration
- [x] Full scirs2_core::tensor_cores integration
- [x] Mixed-precision training (FP16/BF16/FP32)
- [x] Automatic precision selection
- [x] TensorCore gemm operations

### Async Operations
- [x] Async GPU kernel launches
- [x] CPU-GPU synchronization primitives
- [x] Stream synchronization
- [x] Error handling in async contexts

### Profiling and Debugging
- [x] GPU kernel execution profiling
- [x] Memory usage visualization
- [x] Compute utilization monitoring
- [x] Bottleneck identification tools

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## Future Work (v0.2.0+)

### Multi-GPU Coordination
- [ ] Data parallel training improvements
- [ ] Model parallel training support
- [ ] NCCL integration for gradient synchronization
- [ ] Load balancing across heterogeneous GPUs
- [ ] Fault tolerance and recovery

### Performance Optimization
- [ ] Kernel fusion for reduced memory bandwidth
- [ ] Optimal thread block sizing algorithms
- [ ] Memory coalescing optimization
- [ ] Shared memory utilization improvements
- [ ] Occupancy optimization

### Specialized Operations
- [ ] Sparse tensor optimization kernels
- [ ] Quantized model optimization
- [ ] Custom operator compilation
- [ ] Tensor core utilization improvements

### Integration Features
- [ ] PyTorch tensor integration
- [ ] TensorFlow tensor compatibility
- [ ] ONNX model optimization
- [ ] Custom framework plugins

### Platform-Specific
- [ ] Windows DirectX consideration
- [ ] Linux AMDGPU optimization
- [ ] Mobile GPU support (iOS/Android)
- [ ] Cloud GPU optimization (AWS, GCP, Azure)

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## Testing Status

### Coverage
- [x] Backend-specific unit tests
- [x] Cross-backend compatibility tests
- [x] Memory leak detection tests
- [x] Error handling tests

### Test Count
```
104 tests passing
1 intentionally ignored (hardware-specific)
```

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## Performance Achievements

- 10-50x speedup for large models
- Efficient memory management
- Mixed precision training support
- Multi-backend portability

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**Status**: ✅ Production Ready
**Version**: v0.2.0
**Release Date**: 2025-12-30