mindquantum.core.circuit.partial_psi_partial_psi

mindquantum.core.circuit.partial_psi_partial_psi(circuit: Circuit, backend='mqvector')[source]

Calculate the following value of the given parameterized quantum circuit.

\[A_{i,j} = \frac{\partial \left<\psi\right| }{\partial x_{i}} \frac{\partial \left|\psi\right> }{\partial x_{j}}\]

Parameters

circuit (Circuit) – A parameterized quantum circuit.
backend (str) – A supported simulator backend. Please refer description of Simulator. Default: 'mqvector'.

Returns

Function, a function that can calculate inner product of partial psi and partial psi.

Examples

>>> import numpy as np
>>> from mindquantum.core.circuit import partial_psi_partial_psi, Circuit
>>> circ = Circuit().rx('a', 0).ry('b', 0).rz('c', 0)
>>> pppp_ops = partial_psi_partial_psi(circ)
>>> pppp_ops(np.array([1, 2, 3]))
array([[ 0.25      +0.j        ,  0.        +0.13507558j,
        -0.22732436-0.08754387j],
       [ 0.        -0.13507558j,  0.25      +0.j        ,
         0.        +0.12282387j],
       [-0.22732436+0.08754387j,  0.        -0.12282387j,
         0.25      +0.j        ]])