iqm.benchmarks.compressive_gst.mgst.algorithm.B_SFN_riem_Hess

iqm.benchmarks.compressive_gst.mgst.algorithm.B_SFN_riem_Hess#

iqm.benchmarks.compressive_gst.mgst.algorithm.B_SFN_riem_Hess(K: ndarray, A: ndarray, B: ndarray, y: ndarray, J: ndarray, lam: float = 0.001, mle: bool = False) → ndarray#

Riemannian saddle free Newton step on the initial state parametrization.

Parameters:

  • K (ndarray) – Each subarray along the first axis contains a set of Kraus operators. The second axis enumerates Kraus operators for a gate specified by the first axis.

  • A (ndarray) – Current POVM parametrization

  • B (ndarray) – Current initial state parametrization

  • y (ndarray) – 2D array of measurement outcomes for sequences in J; Each column contains the outcome probabilities for a fixed sequence

  • J (ndarray) – 2D array where each row contains the gate indices of a gate sequence

  • lam (float) – Damping parameter for dampled Newton method

  • mle (bool) – Whether to use MLE objective function or least squares objective function

Returns:

Updated initial state parametrization

Return type:

B_new

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