fast element-wise product

[Iakov D.]

Hi,

Is there any routine in gonum (planned?) which allows fast element-wise multiplication of vectors?

Also known as Hadamard product.

It is implemented in GSL under name gsl_vector_mul and v?mul in Intel MKL.

Apparently code generated by golang is not vectorized and is rather slow.

Thanks,

Iakov

[Vladimír Chalupecký]

Hi,

In mat64 there are

func (*Dense) MulElem(a, b Matrix)

func (*Dense) DivElem(a, b Matrix)

for element-wise multiplication and division of matrices, and there are

func (*Vector) MulElemVec(a, b *Vector)

func (*Vector) DivElemVec(a, b *Vector)

for the same operations on vectors.

MKL is fast but the Go compiler is steadily improving, so we face a shining future. We are trying to have the most frequently used operations in assembly on x86_64, there is a big PR on github waiting for review. We welcome any help.

Cheers,

Vladimir