The umbrella header: #include <batchlas.hh> gives the whole public API.
Everything is in namespace batchlas. Every entry point enqueues on a batchlas::Queue and returns a batchlas::Event; nothing is readable until the queue or the event is waited on. Two opt-in headers are not included: <batchlas/blas/device.hh> (in-kernel group BLAS) and <batchlas/sycl_interop.hh> (SYCL types); both need -fsycl.
Definition in file batchlas.hh.
#include <batchlas/blas/linalg.hh>