[feature suggestion] sparse-dense abstraction layer

[owlbarn]

[feature suggestion] sparse-dense abstraction layer

[ryanrhymes]

Good comment, really appreciate it. Indeed, interoperation on different number types is really desirable when fast prototyping. Most of the time in my research, I simply want to try something in utop quickly.

That is actually the motivation of Ext module in Owl. With Ext module, you can do basic math operations on different number types. Please refer to this tutorial: Operators and Ext Module.

But the price we pay for this convenience is: weaker type checking (by wrapping everything in one type) and performance degradation (due to the big match). I haven't really benchmarked about performance degradation yet. However, Ext is just an option for you to do fast prototyping. You can always use the corresponding functions in Owl for better type checking and performance. I think the the ultimate solution is whenever Modular Implicits is included in OCaml official release.

Currently, this interoperation only happens between dense data structures, but Sparse structure is definitely on my todo list. Actually, there is already placeholder in this file for the feature you suggested, I just need to implement the corresponding modules in that file.

Before this happens, I still need to refactor the sparse module a bit (dense module takes me most of the time at the moement).

[nilsbecker]

in my opinion abstracting sparse/dense is tricky. almost by definition, sparse matrices are big -- otherwise one would simply use dense matrices. but for big objects, you really want to be explicit about what you're doing to them, whether new memory is allocated etc. automating this is asking for unexpected out-of-memory situations.