NDTensors.jl incompatible with Optim.jl about ndtensors.jl HOT 4 CLOSED

Sorry, I just noticed this. I'm not sure why I don't get notifications about issues raised, I'll have to look into my settings.

Thanks for pointing that out. It would be great to have ITensors working with Optim. I'll look into the best way to get it working (it may be just adding the solution that Julia recommends).

from ndtensors.jl.

This should be fixed on master and will be included in the next ITensors release (v0.1.38), please let me know if you continue to have problems like this.

from ndtensors.jl.

Hi,

I'm not sure whether I should be posting in this Issue or opening a new one - apologies if the latter. Today I tried using ITensors.jl to do some calculations and had this same problem. If I use a package which depends on ArrayInterface.jl and then try to run, for instance, the first half of the DMRG example script https://itensor.org/docs.cgi?vers=julia&page=getting_started/dmrg :

using ITensors
let
  N = 100
  sites = siteinds("S=1",N)

  ampo = AutoMPO()
  for j=1:N-1
    ampo += "Sz",j,"Sz",j+1
    ampo += 1/2,"S+",j,"S-",j+1
    ampo += 1/2,"S-",j,"S+",j+1
  end
  H = MPO(ampo,sites)
end

I get the same error. I fixed it by extending your fix to accept two integer arguments

# This is needed to fix an ambiguity error with ArrayInterface.jl
# https://github.com/ITensor/NDTensors.jl/issues/62
@propagate_inbounds function setindex(T::EmptyTensor, x, I::Int, J::Int)
  return _setindex(T, x, I, J)
end

I assume this happens because when constructing the MPO from the AutoMPO, ITensors needs to set two indices at once when instantiating the local operators, and the previous solution only fixed it when setting one index.

from ndtensors.jl.

Thanks for pointing that out, I'm fixing it now (more generically by defining setindex(T::EmptyTensor, x, I::Int...)).

from ndtensors.jl.