Why only Matrix3x2 and Matrix4x4?

Question

Why does the System.Numerics namespace define types Matrix3x2 and Matrix4x4 but not offer 2x2 or 3x3 matrices? These would be at least as useful.

Answer 1

(Disclaimer: I work on the System.Numerics libraries at Microsoft)

The comments above are correct. We support a few fixed-size types because they are very commonly used in 2D and 3D graphics applications, for interoperation with core Windows numerics types, as well as for libraries like Win2D.

In the near future, it is likely that we will focus on improving the current types in the library (by adding more and better SIMD code generation capabilities) before we add any new types to the library.