+1 vote
asked by (180 points)

Hello!

Is it possible to reverse only certain arrows of an IQTensor without subclassing or similar tricks?

I can't do something like
conj(dag(iqtensor));

because this reverses all arrow directions.

I made a sketch of the relevant case:
http://imgur.com/7tpfj1g

Best regards and thank you.

1 Answer

+1 vote
answered by (46.3k points)

Hi, I see what you are asking and the sketch that you linked, but could you give me a little more background on why you want to do it? After thinking about it a bit, flipping the arrows is associate with complex conjugation, yet there's no way to "partially" conjugate elements of a tensor.

On the other hand, individual IQIndex arrows could in principle be reversed if the data in the IQTensor was moved into a different pattern of quantum number blocks. But this might be involved to implement so I'd like to better understand the use case.

Best,
Miles

commented by (180 points)
Hi!

I've just discovered that I understood the arrows wrong and that I don't need this kind of operation.
I'm currently working on an implementation for TDVP (http://arxiv.org/abs/1408.5056) in ITensor.
I thought that I need the "Arrow inversion" for the application of the effective Hamiltonian on a Tensor.

Nevertheless, thank you very much for your answer!

Best regards,
Florian
commented by (46.3k points)
Hi Florian,
Ok glad you figured it out!
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