Adds a new non-differentiable primitive `eigh_jacobi` that calls the XLA Jacobi eigh implementation for use inside the TPU QDWH-eigh lowering rule.
PiperOrigin-RevId: 451471088
We need to take only the real part when estimating the median Eigenvalue for splitting, and to return only the real part at termination.
PiperOrigin-RevId: 451406106
Move QDWH-eig from jax._src.scipy.eigh to jax._src.lax.eigh, in preparation for using it to back `lax.eigh` in a future change.
PiperOrigin-RevId: 449362382