Use eigh, eigsh in NumPyEigensolver #6987
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ikkoham
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manoelmarques,
woodsp-ibm and
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What are the 2 notebooks here in this PR - were they added by mistake? |
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Oh... my mistake... Thanks. |
releasenotes/notes/add-opflow-is-hermitian-method-6a461549e3c6b32c.yaml
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Co-authored-by: Jake Lishman <jake@binhbar.com>
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@jakelishman Thank you for your review. I made some mistakes. |
| def is_hermitian(self) -> bool: | ||
| """Return True if the operator is hermitian. | ||
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| Returns: Boolean value | ||
| """ | ||
| return (self.to_spmatrix() != self.to_spmatrix().getH()).nnz == 0 | ||
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With floating-point maths, there's always the thorny question of tolerances to consider. I don't really know if it's appropriate for your use-cases, here, though.
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I agree. Personally, I think OperatorBase should inherit TolerancesMixin. However, the OpFlow implementation does not do so. e.g. https://github.com/Qiskit/qiskit-terra/blob/d2013d1812c9229455c1cfb1c79c560fecbc5dfe/qiskit/opflow/primitive_ops/pauli_op.py#L90
The concept of equality is different between Opflow and quantum_info.operators. opflow is exact and qinfo allows errors.
I believe that it should be unified in the future, but this is beyond the scope of this PR, so please leave it for now.
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Sounds fine to me, then - definitely best just to follow what's already there in this case!
…b32c.yaml Co-authored-by: Jake Lishman <jake@binhbar.com>
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Changelog: New Feature
* Use eigh, eigsh * add is_hermitian method * add is_hermitian method to OperatorBase * rm unnecessary files * modify releasenot * Apply suggestions from code review Co-authored-by: Jake Lishman <jake@binhbar.com> * fix test name * Update releasenotes/notes/add-opflow-is-hermitian-method-6a461549e3c6b32c.yaml Co-authored-by: Jake Lishman <jake@binhbar.com> Co-authored-by: Jake Lishman <jake@binhbar.com>
* Use eigh, eigsh * add is_hermitian method * add is_hermitian method to OperatorBase * rm unnecessary files * modify releasenot * Apply suggestions from code review Co-authored-by: Jake Lishman <jake@binhbar.com> * fix test name * Update releasenotes/notes/add-opflow-is-hermitian-method-6a461549e3c6b32c.yaml Co-authored-by: Jake Lishman <jake@binhbar.com> Co-authored-by: Jake Lishman <jake@binhbar.com>
Summary
If NumPyEigensSolver knows that the given operator is hermitian, we should use eigh or eigsh.
The eigenvalue becomes float from complex.
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