Error for basic ITensor contraction

ITensor Julia Questions
1

Hi,

I’m getting an error in my code that wasn’t there before. It also shows up if I use example code, so I’m not sure if this is a bug from an updated version. The following code is from the ITensor website,

i = Index(2,“index_i”); j = Index(4,“index_j”); k = Index(3,“index_k”)

A = randomITensor(i,j)
B = randomITensor(j,k)
C = A * B # contract over Index j

A = randomITensor(i,i’)
B = randomITensor(i,i’')
C = A * B # contract over Index i

A = randomITensor(i)
B = randomITensor(j)
C = A * B # outer product of A and B, no contraction

A = randomITensor(i,j,k)
B = randomITensor(k,i,j)
C = A * B # inner product of A and B, all indices contracted.

If I run this after importing ITensor, I get the following error
no method matching to_shape(::Tuple{Index{Int64}, Index{Int64}}).

Any help would be greatly appreciated.

2

Thanks for posting this, but I don’t get any error when I run your code on my machine. Here’s the exact code that I ran (I personally am suspicious of running code in global scope so I put mine into a let...end block.)

using ITensors

let
  i = Index(2,"index_i"); j = Index(4,"index_j"); k = Index(3,"index_k")

  A = randomITensor(i,j)
  B = randomITensor(j,k)
  C = A * B # contract over Index j

  A = randomITensor(i,i')
  B = randomITensor(i,i'')
  C = A * B # contract over Index i

  A = randomITensor(i)
  B = randomITensor(j)
  C = A * B # outer product of A and B, no contraction

  A = randomITensor(i,j,k)
  B = randomITensor(k,i,j)
  C = A * B # inner product of A and B, all indices contracted.
  return
end

Can you please check that you are upgraded to the most recent version of ITensors.jl?

3

Hi,

Thanks for the reply! Yes, turns out it was sorted when I updated my ITensor.jl.

1 Like
4

Glad to hear it!