QubitOperator('X0 X0') should simplify to the identity

[kevinsung]

Instead, it prints out to

1.0 [X0 X0]

[kevinsung]

There's a similar thing with FermionOperator, which is that FermionOperator('0^ 0^') does not simplify to zero. However, we have normal_ordered to simplify FermionOperators, while there is no analogous function for QubitOperators. But since simplifying QubitOperators is cheap (and normal-ordering is expensive), I think it makes sense to deal with this kind of stuff upon initialization.

[kevinsung]

Also, QubitOperator('X0 Y0') should simplify to i Z0.

[babbush]

I mean, if we're going to do this I guess it should be able to do arbitrary multiplication. E.g. it should know how to interpret "X0 Y1 Z3 X2 Z3 Y0", right?

[kevinsung]

Yeah.

…

On Fri, Sep 14, 2018, 5:47 PM Ryan Babbush ***@***.***> wrote: I mean, if we're going to do this I guess it should be able to do arbitrary multiplication. E.g. it should know how to interpret "X0 Y1 Z3 X2 Z3 Y0", right? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#446 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEGN5tQfgw7BYefd3_AYQNjctjEZO77Fks5ubDHwgaJpZM4Wb4bI> .