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More optional history logging #95

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jarlebring
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@jarlebring jarlebring commented Jan 19, 2019

This adds additional optional logging. This is useful when the Arnoldi-method fails.

It is e.g. quite easy to investigate what is going wrong in #93 with this:

@load "myerror.jld2" W
local history;
for k=1:30
    decomp, history = partialschur(W, nev=3, which=LR(), tol=1e-13, history_level=DetailedHistory);
    λ, V = partialeigen(decomp);
    if (abs(maximum(real(λ)) - maximum(real(eigvals(W)))) > 1e-6)
        break;
   end
end

The eigenvalues that should be computed are

julia> e=eigvals(W); II=sortperm(-real(e)); e[II[1:3]]
3-element Array{Complex{Float64},1}:
  0.15368465993022115 + 0.0im                  
 9.871248233586328e-9 + 1.0327891056793643e-8im
 9.871248233586328e-9 - 1.0327891056793643e-8im

It seems the two last eigenvalues are incorrectly locked in the first restart:

julia> history.ritzval_history[1][history.ritzval_lock_history[1]]
2-element Array{Complex{Float64},1}:
 3.5489275362237446e-7 + 0.00012663869814285724im
 3.5489275362237446e-7 - 0.00012663869814285724im

The PR is not quite ready yet. Putting it here for comments. What should be collected?

@haampie
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haampie commented Jan 19, 2019

Thanks! I will try it probably tomorrow :)

@haampie
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haampie commented Feb 22, 2024

Thanks! I will try it probably tomorrow :)

That did not happen.

I think I'll close this since it out of date, but can come back to it if necessary at some point.

@haampie haampie closed this Feb 22, 2024
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2 participants