cachefriendlyproduct, that should be banned as well as depending on the
platform they can give a malloc, and they could happen even with (large
enough) fixed size matrices. Corresponding fix in Product.h:
cachefriendly is now only used for dynamic matrices -- fixedsize, no
matter how large, doesn't use the cachefriendly product. We don't need
to care (in my opinion) about performance for large fixed size, as large
fixed size is a bad idea in the first place and it is more important to
be able to guarantee clearly that fixed size never causes a malloc.
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