Hey all, I am trying to implement the TDVP function, and I get some weird error that I couldn’t figure out what is the reason. Basically, I am trying the develop in imaginary time the following wave function |\psi_0 \rangle = |0...0\rangle \\ |\psi \rangle= \frac{e^{-\beta H}|\psi_0 \rangle}{ |…

I think here it might solve your problem to rewrite your Hamiltonian in terms of the “S+” and “S-” operators instead of “Sy” and “Sx”. This is because “S+” and “S-” are real-valued so you would not encounter any complex numbers that way.

Hey, No. If you wish I can share it here

Yeah, please share a full minimal example that reproduces that bug. It’s not clear to me why a complex number would be showing up, it may be an issue with the applyexp solver backend. As an alternative you could try the exponentiate backend, which makes use of KrylovKit.jl, by passing the keyword ar…

Hey, Sorry for the mistake. The Hamiltonian includes the “Sy” operator, but when I applied only “Sy”, it did not printed an error. The Hamiltonian: J=randn(n,n,3,3) os = OpSum() A = ["Sx", "Sy", "Sz"] for j in 1:n-1 for i in j+1:n for α in 1:3 f…

Hey miles! thank you for your comment. I will try that

Related issue: Fix complex issue in applyexp solver · Issue #49 · ITensor/ITensorTDVP.jl · GitHub and discourse thread: tdvp time developing

@miles we should probably just change the default backend to "exponentiate".

I have been met the problem, and you just need a command to solve it, i.e, MPS(ComplexF64, s)

Errors in TDVP function

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mtfishman June 1, 2023, 6:39pm 9

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Errors in TDVP function

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