forked from Qiskit/qiskit
-
Notifications
You must be signed in to change notification settings - Fork 1
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Oxidize parameter calculation for OneQubitEulerDecomposer (Qiskit#9185)
* Oxidize parameter calculation for OneQubitEulerDecomposer This commit ports the per basis parameter calculation from python to rust. In looking at the runtime performance regression caused by Qiskit#8917 the majority is just that we're doing more work synthesizing to more available basis to potentially produce better quality results. Profiling the transpiler pass shows we're spending a non-trivial amount of time in numpy/scipy (depending on whether it's before or after Qiskit#9179) computing the determinant of the unitary. This is likely because those determinant functions are designed to work with an arbitrarily large square matrix while for the 1 qubit decomposer we're only ever working with a 2x2. To remove this overhead this commit writes a dedicated rust function to compute the determinant of a 2x2 complex matrix and then also adds dedicated functions to calculate the angles for given basis to rust as we can easily just return the end result from rust. Related Qiskit#8774 * Eliminate python function for staticmethod definition This commit removes one layer of function calls for the OneQubitEulerDecomposer's staticmethods for calculating parameters. Previously, there was a python function which called an inner rust function, this eliminates one layer and attaches the rust function directly as a static method to the class definition.
- Loading branch information
Showing
4 changed files
with
130 additions
and
69 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,118 @@ | ||
| // This code is part of Qiskit. | ||
| // | ||
| // (C) Copyright IBM 2022 | ||
| // | ||
| // This code is licensed under the Apache License, Version 2.0. You may | ||
| // obtain a copy of this license in the LICENSE.txt file in the root directory | ||
| // of this source tree or at http://www.apache.org/licenses/LICENSE-2.0. | ||
| // | ||
| // Any modifications or derivative works of this code must retain this | ||
| // copyright notice, and modified files need to carry a notice indicating | ||
| // that they have been altered from the originals. | ||
|
|
||
| use num_complex::{Complex64, ComplexFloat}; | ||
| use pyo3::prelude::*; | ||
| use pyo3::wrap_pyfunction; | ||
| use pyo3::Python; | ||
| use std::f64::consts::PI; | ||
|
|
||
| use ndarray::prelude::*; | ||
| use numpy::PyReadonlyArray2; | ||
|
|
||
| #[inline] | ||
| fn det_one_qubit(mat: ArrayView2<Complex64>) -> Complex64 { | ||
| mat[[0, 0]] * mat[[1, 1]] - mat[[0, 1]] * mat[[1, 0]] | ||
| } | ||
|
|
||
| #[inline] | ||
| fn complex_phase(x: Complex64) -> f64 { | ||
| x.im.atan2(x.re) | ||
| } | ||
|
|
||
| #[inline] | ||
| fn mod_2pi(angle: f64) -> f64 { | ||
| (angle + PI) % (2. * PI) - PI | ||
| } | ||
|
|
||
| fn params_zyz_inner(mat: ArrayView2<Complex64>) -> [f64; 4] { | ||
| let coeff: Complex64 = 1. / det_one_qubit(mat).sqrt(); | ||
| let phase = -complex_phase(coeff); | ||
| let tmp_1_0 = (coeff * mat[[1, 0]]).abs(); | ||
| let tmp_0_0 = (coeff * mat[[0, 0]]).abs(); | ||
| let theta = 2. * tmp_1_0.atan2(tmp_0_0); | ||
| let phiplambda2 = complex_phase(coeff * mat[[1, 1]]); | ||
| let phimlambda2 = complex_phase(coeff * mat[[1, 0]]); | ||
| let phi = phiplambda2 + phimlambda2; | ||
| let lam = phiplambda2 - phimlambda2; | ||
| [theta, phi, lam, phase] | ||
| } | ||
|
|
||
| fn params_zxz_inner(mat: ArrayView2<Complex64>) -> [f64; 4] { | ||
| let [theta, phi, lam, phase] = params_zyz_inner(mat); | ||
| [theta, phi + PI / 2., lam - PI / 2., phase] | ||
| } | ||
|
|
||
| #[pyfunction] | ||
| pub fn params_zyz(unitary: PyReadonlyArray2<Complex64>) -> [f64; 4] { | ||
| let mat = unitary.as_array(); | ||
| params_zyz_inner(mat) | ||
| } | ||
|
|
||
| #[pyfunction] | ||
| pub fn params_xyx(unitary: PyReadonlyArray2<Complex64>) -> [f64; 4] { | ||
| let mat = unitary.as_array(); | ||
| let mat_zyz = arr2(&[ | ||
| [ | ||
| 0.5 * (mat[[0, 0]] + mat[[0, 1]] + mat[[1, 0]] + mat[[1, 1]]), | ||
| 0.5 * (mat[[0, 0]] - mat[[0, 1]] + mat[[1, 0]] - mat[[1, 1]]), | ||
| ], | ||
| [ | ||
| 0.5 * (mat[[0, 0]] + mat[[0, 1]] - mat[[1, 0]] - mat[[1, 1]]), | ||
| 0.5 * (mat[[0, 0]] - mat[[0, 1]] - mat[[1, 0]] + mat[[1, 1]]), | ||
| ], | ||
| ]); | ||
| let [theta, phi, lam, phase] = params_zyz_inner(mat_zyz.view()); | ||
| let new_phi = mod_2pi(phi + PI); | ||
| let new_lam = mod_2pi(lam + PI); | ||
| [ | ||
| theta, | ||
| new_phi, | ||
| new_lam, | ||
| phase + (new_phi + new_lam - phi - lam) / 2., | ||
| ] | ||
| } | ||
|
|
||
| #[pyfunction] | ||
| pub fn params_xzx(unitary: PyReadonlyArray2<Complex64>) -> [f64; 4] { | ||
| let umat = unitary.as_array(); | ||
| let det = det_one_qubit(umat); | ||
| let phase = (Complex64::new(0., -1.) * det.ln()).re / 2.; | ||
| let sqrt_det = det.sqrt(); | ||
| let mat_zyz = arr2(&[ | ||
| [ | ||
| Complex64::new((umat[[0, 0]] / sqrt_det).re, (umat[[1, 0]] / sqrt_det).im), | ||
| Complex64::new((umat[[1, 0]] / sqrt_det).re, (umat[[0, 0]] / sqrt_det).im), | ||
| ], | ||
| [ | ||
| Complex64::new(-(umat[[1, 0]] / sqrt_det).re, (umat[[0, 0]] / sqrt_det).im), | ||
| Complex64::new((umat[[0, 0]] / sqrt_det).re, -(umat[[1, 0]] / sqrt_det).im), | ||
| ], | ||
| ]); | ||
| let [theta, phi, lam, phase_zxz] = params_zxz_inner(mat_zyz.view()); | ||
| [theta, phi, lam, phase + phase_zxz] | ||
| } | ||
|
|
||
| #[pyfunction] | ||
| pub fn params_zxz(unitary: PyReadonlyArray2<Complex64>) -> [f64; 4] { | ||
| let mat = unitary.as_array(); | ||
| params_zxz_inner(mat) | ||
| } | ||
|
|
||
| #[pymodule] | ||
| pub fn euler_one_qubit_decomposer(_py: Python, m: &PyModule) -> PyResult<()> { | ||
| m.add_wrapped(wrap_pyfunction!(params_zyz))?; | ||
| m.add_wrapped(wrap_pyfunction!(params_xyx))?; | ||
| m.add_wrapped(wrap_pyfunction!(params_xzx))?; | ||
| m.add_wrapped(wrap_pyfunction!(params_zxz))?; | ||
| Ok(()) | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters