jacobian

Module: pennylane

jacobian(func, argnum)[source]

Returns the Jacobian as a callable function of vector-valued (functions of) QNodes.

This is a wrapper around the autograd.jacobian function.

Parameters:
  • func (function) – a vector-valued Python function or QNode that contains a combination of quantum and classical nodes. The output of the computation must consist of a single NumPy array (if classical) or a tuple of expectation values (if a quantum node)
  • argnum (int or Sequence[int]) – which argument to take the gradient with respect to. If a sequence is given, the Jacobian matrix corresponding to all input elements and all output elements is returned.
Returns:

the function that returns the Jacobian of the input function with respect to the arguments in argnum

Return type:

function