pygsti.objects.GateSet.hpr

GateSet.hpr(spamLabel, gatestring, returnPr=False, returnDeriv=False, clipTo=None)

Compute the Hessian of a probability generated by a gate string and spam label as a 1 x M x M array, where M is the number of gateset parameters.

Parameters:
  • spamLabel (string) – the label specifying the state prep and measure operations
  • gatestring (GateString or tuple of gate labels) – The sequence of gate labels specifying the gate string.
  • returnPr (bool, optional) – when set to True, additionally return the probability itself.
  • returnDeriv (bool, optional) – when set to True, additionally return the derivative of the probability.
  • clipTo (2-tuple, optional) – (min,max) to clip returned probability to if not None. Only relevant when returnPr == True.
Returns:

  • hessian (numpy array) – a 1 x M x M array, where M is the number of gateset parameters. hessian[0,j,k] is the derivative of the probability w.r.t. the k-th then the j-th gateset parameter.
  • derivative (numpy array) – only returned if returnDeriv == True. A 1 x M numpy array of derivatives of the probability w.r.t. each gateset parameter.
  • probability (float) – only returned if returnPr == True.