kalmar/PropertyT.jl
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Sparsification of a dense matrix is not required to be rank preserving

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This can bite!
This commit is contained in:
kalmarek 2017-08-27 21:23:14 +02:00
parent 972697e2ba
commit 6df4c790c0
1 changed files with 9 additions and 14 deletions
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23
src/Orbit-wise.jl
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@ -72,23 +72,18 @@ function sparsify!{Tv,Ti}(M::SparseMatrixCSC{Tv,Ti}, eps=eps(Tv))
return M
end
function sparsify!{T}(U::AbstractArray{T}, eps=eps(T); check=true)
if check
W = deepcopy(U)
else
W = U
function sparsify!{T}(M::AbstractArray{T}, eps=eps(T); check=false, verbose=false)
densM = dens(M)
rankM = rank(M)
M[abs.(M) .< eps] .= zero(T)
if check && rankM != rank(M)
warn(logger, "Sparsification decreased the rank!")
end
W[abs.(W) .< eps] .= zero(T)
if check
info("Sparsification would decrease the rank!")
W = U
else
info("Sparsified density:", rpad(dens(U), 15), "→", rpad(dens(W),15))
end
W = sparse(W)
return W
return M
end
sparsify{T}(U::AbstractArray{T}, tol=eps(T)) = sparsify!(deepcopy(U), tol)