I have the problem when I run my code

# define Hamiltonian
from qiskit.opflow import PauliSumOp, X, I, Z, Y
H = ((X^(I)^I))+ (X^I^I) + ((X^(I^(2))*2/2)/2) + (X^I^I) + (X^Z^I) + (X^I^I/3)
H += (I^I^X)


the result is

3.5 * XII
+ 1.0 * XZI
+ 0.3333333333333333 * XII
+ 1.0 * IIX

The problem is I don't know why the qiskit.opflow doesn't combine two terms of XII tensor together. I have worked on it for a while but have not worked, so I hope for your help, tks.


1 Answer 1


You will need to call reduce() method to simplify it:

  • $\begingroup$ Oh, thanks. Really appreciate $\endgroup$ Feb 28, 2023 at 7:15

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