Issue with latest version of TDVP

ITensor Julia Questions
1

Hi,

The below code seems to run more slowly using version 0.4.10 as opposed to 0.3.0. Any help would be much appreciated.

using Pkg

Pkg.rm(“ITensorTDVP”)

Pkg.add(PackageSpec(name=“ITensorTDVP”, version=“0.4.10”))

using ITensorTDVP

using ITensors

@show(pkgversion(ITensorTDVP))

@show(pkgversion(ITensors))

N = 50

sites = siteinds(“S=1/2”,N)

os = OpSum()

for j=1:N-2

os += “Sz”,j,“Sz”,j+2

os += 1/2,“S+”,j,“S-”,j+2

os += 1/2,“S-”,j,“S+”,j+2

end

H = MPO(os,sites)

psi0 = randomMPS(sites;linkdims=10)

nsweeps = 5

maxdim = 50

cutoff = [1E-10]

# Compile the code first
ITensorTDVP.tdvp(H,-0.1im,psi0;nsweeps,maxdim,cutoff,outputlevel=0)
if pkgversion(ITensorTDVP) == v"0.4.10"
@time psi = ITensorTDVP.tdvp(H,-0.1im,psi0;nsweeps,maxdim,cutoff,outputlevel=1)
elseif pkgversion(ITensorTDVP) == v"0.3.0"
@time psi = ITensorTDVP.tdvp(H,-0.02im,psi0;nsweeps,maxdim,cutoff,outputlevel=1)
end
2

Hello David,

Can you please report your timing data? Also can you please report on your versioninfo and what computer system you are working with?

Thanks,
Karl

3

Closing because this will be discussed in Newer version of TDVP seems to be much slower. @DavidStrachan1 you should be able to edit your previous post to fix the formatting.

1 Like