qrisp.gqsp.qsp_angles#

qsp_angles(p: ArrayLike, parity: Literal['even', 'odd'] = 'odd', signal_basis: Literal['X', 'Z'] = 'Z') tuple[Array, Array][source]#

Computes the QSP angles for a given polynomial.

Parameters:
pArrayLike

1-D array containing the polynomial coefficients in Chebyshev basis, ordered from lowest order term to highest.

parityLiteral[“even”, “odd”]

The structural parity of the target polynomial (‘even’ or ‘odd’). Defaults to ‘odd’. Must be known at compile time for JAX tracing.

signal_basisLiteral[“X”, “Z”]

The signal basis for the QSP angles (‘X’ or ‘Z’). Defaults to ‘Z’.

Returns:
anglesArray

1-D array of angles \((\phi_0,\dotsc,\phi_d)\).

alphaArray

The scalar scaling factor as 0-D array.

Notes

  • The resulting angles correspond to a rescaled version of the input polynomial.