The [ChessBoardDemixing](https://github.com/MPF-Optimization-Laboratory/AtomicOpt.jl/blob/main/examples/ChessBoard/ChessBoardDemixing.ipynb) example fails on this line in [align](https://github.com/MPF-Optimization-Laboratory/AtomicOpt.jl/blob/831bf00a4e07036dca16e86358cba5b2b88ebfc2/src/Optimization/align.jl#L78) because the dotted vectors are sparse, but `BLAS.axpy` only works for dense vectors.
The ChessBoardDemixing example fails on this line in align because the dotted vectors are sparse, but
BLAS.axpyonly works for dense vectors.