I have a 2D array, and want to treat each row (or column) as a vector and find norm of it a = [1 2 3 ; 4 5 6] a 2×3 Array{Int64,2}: 1 2 3 4 5 6 The following is what I have tried and their results. Both norm.(a) and vecnorm.(a) gives 2×3 Array{Int64,2}: 1 2 3 4 5 6 While norm(a) gi…

There is currently no direct function to take the norm of a 2D array by dimension. The easiest way would probably be to do either of the 2 functions below: julia> A = rand(5,4); julia> f1(A,d=1) = sqrt.(sum(abs2,A,d)) f1 (generic function with 1 method) …

While f1 is likely to always be the best, f2 can be made slightly faster by replacing A[:,i] with @view A[:,i] to avoid the copy operation. Another alternative is to use mapslices which applies a specified function to slices through the matrix (much like is being done manually with f2) julia> f3(A…

Thanks for your additional info. I also found this discussion . Good to learn another new thing.

Maybe it is more intuitive think about list comprehension in this kind of problem (any problem with operation across matrices and vectors, really). My favorite way to get a list of norms of the vectors represented as lines in a matrix is : norms = [norm(m[i,:]) for i=1:size(m)[1]] It is not super…

"vecnorm" : column/row-wise norm

New to Julia

nilshg May 21, 2021, 5:06am 6

Or just norm.(eachcol(m))

Orders of magnitude runtime difference in row-wise norm

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"vecnorm" : column/row-wise norm

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