Rewrite svd to avoid empty blocks

[lkdvos]

This avoids looping over blocks that will end up being truncated completely, ie that would get howmany = 0.

This probably fixes #185, although I don't have an explicit case to check this on.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files with missing lines	Coverage Δ
src/utility/svd.jl	87.05% <100.00%> (+0.11%)	⬆️

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[Confusio]

This avoids looping over blocks that will end up being truncated completely, ie that would get howmany = 0.

This probably fixes #185, although I don't have an explicit case to check this on.

Thanks for the fixing. This will come out if we set svd_alg=SVDAdjoint(; fwd_alg=IterSVD()) in the boundary_alg in the following example:

PEPSKit.jl/examples/xxz/main.jl

Line 74 in 7254747

boundary_alg = (; tol=1e-8, alg=:simultaneous, trscheme=(; alg=:fixedspace))

[pbrehmer]

Thanks for catching and fixing that!