Hey guys, I am quite a beginner at using Julia and this is my first post, so apologies if there is an obvious answer! I would like to find out if there is an easy way to perform the sumproduct excel function in Julia. As an example, I currently have the following vectors: vec_1 = [a,b,c] vec_2 =…

Any reason not to do: cumsum(vec_1 .* vec_2)

This is an inner product (a dot product). vec_1' * vec_2 (or just vec_1'vec_2) will do what you want. Sorry, I misread your question; this is cumsum(vec_1 .* vec_2). (Technically, if your vectors are complex numbers, then vec_1' * vec_2 will also conjugate the elements of vec_1 in the product. I…

That only gives the last element though. Maybe something like julia> a, b, c, e, f, g = 1:6; julia> vec_1 = [a,b,c]; julia> vec_2 = [e,f,g]; julia> cumsum(x*y for (x,y) in zip(vec_1, vec_2)) 3-element Array{Int64,1}: 4 14 32

The intermediate allocation of vec_1 .* vec_2 I guess.

[image] fredrikekre: [image] johnmyleswhite: Any reason not to do: cumsum(vec_1 .* vec_2) The intermediate allocation of vec_1 .* vec_2 I guess. Probably a premature optimization for someone porting from Excel…

Thanks for the quick responses guys, the cumsum(vec_1.*vec_2) was exactly what I was after. Happy Friday!

Sumproduct function in Julia

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Sumproduct function in Julia

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