remove MatMul f32 special case (smaller code),
types: Add u32/u64 for use by Activations
move renamed ParallelismStrategy to threading_context so can pass ctx
ensure worker index is unique across clusters
matmul.h: const member functions for renamed policy classes (easier to call)
PiperOrigin-RevId: 802848086
Precompute row pointers.
Remove no longer used MHA support; QStride -> qkv_dim.
Remove RowPtr from MatMul interface, use only MatPtrT.
Require opt-in define for NUQ to speed up builds.
Also fix io.cc on Windows.
PiperOrigin-RevId: 766228108
Jan Wassenberg