+1 vote
asked by (320 points)


I use the latest version of the AutoMPO to construct a four-body fermion term like Ci+1^{\dag}Ci^{\dag}CjCj+1 but I encounter an error message as followings:

Invalid input to AutoMPO (two strings in a row?)

Is there any restriction in constructing a general two-body interaction using latest AutoMPO? Thank you.

1 Answer

+1 vote
answered by (70.1k points)

Hi, so I've been using the code for precisely this purpose and didn't encounter such an error message. Can you verify that you are on the very latest commit of the master branch (i.e. did a git pull from github) and did a complete recompile of the library?

commented by (320 points)
Yes, I download I-Tensor 2 from GitHub and type
>>git pull origin master
and recompile (make clean || make).
Is there any step I miss?
Thank you
commented by (70.1k points)
Ok, so it seems the problem is that your input to AutoMPO is simply not valid input. This doesn't have to do with the number of operators, but you have to following pattern:
ampo += coef,string,integer,string,integer, ....;
So like:
ampo += 0.5,"Cdagup",i,"Cup",j;

Please look at the code example I posted in the comment in the other thread and use that code as a pattern to follow for your own code.
commented by (320 points)
Hi, I found my problem. It is my fault. Thank you for your help.
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