Expression system requires evaluation in many contexts

[spectre-ns]

I'm trying to figure out why the code snippet requires assignment to a concrete xarray or xt::eval called to compile. I should be able to make these all auto and do it lazily right?

Am I doing something wrong? Adding SIMD support requires me to add an extra eval when calculating angle:

The snippet above doesn't compile with the following error:
Error C2664 'xsimd::batch<T,xsimd::default_arch> xsimd::batch<T,xsimd::default_arch>::load_unaligned(const double *,const double *)': cannot convert argument 1 from 'const T *' to 'const T *' \xtensor\xiterator.hpp 560

Finally, I expect this to work but it doesn't:

We the following error
Error C2296 '%': illegal, left operand has type '_Ty' xtensor\xoperation.hpp 111

Any thoughts?

[JohanMabille]

As soon as you want to assign something to an expression, this expression has to hold memory, it cannot be an unevaluated builder.

Regarding the errors you have, can you provide the full stacktrace?