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Pass correct views to SymTridiagonal #157

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Merged
Jutho merged 1 commit into from
May 6, 2026
Merged

Pass correct views to SymTridiagonal #157

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4 changes: 3 additions & 1 deletion src/factorizations/lanczos.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,9 @@ function basis(F::LanczosFactorization)
return length(F.V) == F.k ? F.V :
error("Not keeping vectors during Lanczos factorization")
end
rayleighquotient(F::LanczosFactorization) = SymTridiagonal(F.αs, F.βs)
function rayleighquotient(F::LanczosFactorization)
return SymTridiagonal(view(F.αs, 1:(F.k)), view(F.βs, 1:(F.k - 1)))
end
residual(F::LanczosFactorization) = F.r
@inbounds normres(F::LanczosFactorization) = F.βs[F.k]
rayleighextension(F::LanczosFactorization) = SimpleBasisVector(F.k, F.k)
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7 changes: 7 additions & 0 deletions test/issues.jl
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Expand Up @@ -27,3 +27,10 @@ end
@test info.numops == 2
@test info.normres == 0.0
end

# https://github.com/Jutho/KrylovKit.jl/issues/156
@testset "Issue #156" begin
vals, vecs, info = eigsolve([1 0; 0 1])
@test info.converged ≥ 1
@test all(≈(1.0), vals[1:(info.converged)])
end
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