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dq.timecallable 

timecallable(
    f: callable[[float], QArray], *, discontinuity_ts: ArrayLike | None = None
) -> CallableTimeQArray

Instantiate a callable time-qarray.

A callable time-qarray is defined by \(O(t) = f(t)\) where \(f(t)\) is a time-dependent operator. The function \(f\) is defined by passing a Python function with signature f(t: float) -> QArray that returns a qarray of shape (..., n, n) for any time \(t\).

The function f must return a qarray (not a qarray-like!)

An error is raised if the function f does not return a qarray. This error concerns any other qarray-likes. This is enforced to avoid costly conversions at every time step of the numerical integration.

Parameters

  • f (function returning qarray of shape (..., n, n)) –

    Function with signature (t: float) -> QArray that returns the qarray \(f(t)\).

  • discontinuity_ts (array-like, optional) –

    Times at which there is a discontinuous jump in the function values.

Returns

(time-qarray of shape (..., n, n) when called) Callable returning \(O(t)\) for any time \(t\).

Examples 

>>> f = lambda t: dq.asqarray([[t, 0], [0, 1 - t]])
>>> H = dq.timecallable(f)
>>> H(0.5)
QArray: shape=(2, 2), dims=(2,), dtype=float32, layout=dense
[[0.5 0. ]
 [0.  0.5]]
>>> H(1.0)
QArray: shape=(2, 2), dims=(2,), dtype=float32, layout=dense
[[1. 0.]
 [0. 0.]]