Add shift kwarg to solve_fermion #201
Conversation
| If ``None``, no spin will be imposed. | ||
| shift: Level shift for states which have different spin. :math:`(H + shift * S^2)|ψ> = E|ψ>` |
There was a problem hiding this comment.
maybe this equation should go up in the spin_sq description? Maybe even in top-level description of this function?
|
@kevinsung it seems like if you pass a |
|
Actually, we should set a default numerical value for the |
qiskit_addon_sqd/fermion.py
Outdated
| @@ -75,6 +75,7 @@ def solve_fermion( | |||
| *, | |||
| open_shell: bool = False, | |||
| spin_sq: float | None = None, | |||
| shift: float | None = None, | |||
There was a problem hiding this comment.
As I mentioned in the comment, we should make the default a number. From https://pyscf.org/_modules/pyscf/fci/addons.html it's either 0.2 or 0.1, but it's unclear which one. To be sure, we would need to run some code and print it out or use the debugger.
There was a problem hiding this comment.
We have been calling fix_spin_ with the default value, so I think 0.1 is what has been the default for us
There was a problem hiding this comment.
I decided to make the type hint float and cast to np.float64 inside. The linter didn't want me to use np.float64() in the annotation. I could do shift: np.number | float = 0.1, but I figured this is fine
qiskit_addon_sqd/fermion.py
Outdated
| if isinstance(bitstring_matrix, tuple): | ||
| ci_strs = bitstring_matrix | ||
| else: | ||
| ci_strs = bitstring_matrix_to_ci_strs(bitstring_matrix, open_shell=open_shell) | ||
| ci_strs = _check_ci_strs(ci_strs) | ||
| shift = np.float64(shift) |
There was a problem hiding this comment.
Does the code actually break without this type conversion?
There was a problem hiding this comment.
No I just did it bc its what pyscf says it wants
There was a problem hiding this comment.
Ok. In that case, I think you can delete it.
|
I think we need to change the default spin_sq to |
I did that for the |
Fixes #139