cirq.qis.bloch_vector_from_state_vector

Returns the bloch vector of a qubit.

Used in the notebooks

Used in the tutorials

Calculates the bloch vector of the qubit at index in the state vector, assuming state vector follows the standard Kronecker convention of numpy.kron.

state_vector A sequence representing a state vector in which the ordering mapping to qubits follows the standard Kronecker convention of numpy.kron (big-endian).
index index of qubit who's bloch vector we want to find. follows the standard Kronecker convention of numpy.kron.
qid_shape specifies the dimensions of the qudits for the input state_vector. If not specified, qubits are assumed and the state_vector must have a dimension a power of two. The qudit at index must be a qubit.

A length 3 numpy array representing the qubit's bloch vector.

ValueError if the size of state_vectoris not a power of 2 and the shape is not given or if the shape is given and state_vector has a size that contradicts this shape.
IndexError if index is out of range for the number of qubits or qudits corresponding to state_vector.