Hallo, Do you know ‘good’ ways to refactor a symmetric matrix into a vector, and back again? Ideally, something like this: A = [1 2 3; 2 4 5; 3 5 6] V = mat2vec(A) # V = [1 2 3 4 5 6] A = vec2mat(V) # A = [1 2 3; 2 4 5; 3 5 6] Many thanks,

[image] ignace: Do you know ‘good’ ways to refactor a symmetric matrix into a vector, See Vector of upper triangle GitHub - JaneliaSciComp/SymmetricFormats.jl: efficient storage for symmetric matrices

Maybe it’s not a “good” way in the sense you expect, but in some cases it could work julia> function symmat2vec(m) n=size(m,1) N=n*(n+1)÷2 v=Vector{eltype(m)}(undef,N) for idx in 1: N j = Int(ceil(sqrt(2 * idx + 0.25) - 0.5)) …

Refactoring a symmetric matrix into a vector and back again

General Usage

stevengj October 25, 2023, 2:37pm 2

See

Vector of upper triangle
GitHub - JaneliaSciComp/SymmetricFormats.jl: efficient storage for symmetric matrices

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Refactoring a symmetric matrix into a vector and back again

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