Are numpy's basic operations vectorized, i.e. do they use SIMD operations?
Yes, they are.
/*
* This file is for the definitions of simd vectorized operations.
*
* Currently contains sse2 functions that are built on amd64, x32 or
* non-generic builds (CFLAGS=-march=...)
* In future it may contain other instruction sets like AVX or NEON detected
* at runtime in which case it needs to be included indirectly via a file
* compiled with special options (or use gcc target attributes) so the binary
* stays portable.
*/
Link: Numpy simd.inc.src on github.