internalgates.py

"""
The standard unitaries and gate names, used internal compilers and short-hand model init
"""
#***************************************************************************************************
# Copyright 2015, 2019 National Technology & Engineering Solutions of Sandia, LLC (NTESS).
# Under the terms of Contract DE-NA0003525 with NTESS, the U.S. Government retains certain rights
# in this software.
# Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
# in compliance with the License.  You may obtain a copy of the License at
# http://www.apache.org/licenses/LICENSE-2.0 or in the LICENSE file in the root pyGSTi directory.
#***************************************************************************************************

import numpy as _np
import scipy.linalg as _spl

from pygsti.tools import optools as _ot
from pygsti.tools import symplectic as _symp
from pygsti.baseobjs.unitarygatefunction import UnitaryGateFunction as _UnitaryGateFunction


class Gzr(_UnitaryGateFunction):
    shape = (2, 2)

    def __call__(self, theta):
        return _np.array([[1., 0.], [0., _np.exp(-1j * float(theta[0]))]])

    @classmethod
    def _from_nice_serialization(cls, state):
        return super(Gzr, cls)._from_nice_serialization(state)


class Gczr(_UnitaryGateFunction):
    shape = (4, 4)

    def __call__(self, theta):
        return _np.array([[1., 0., 0., 0.], [0., 1., 0., 0.], [0., 0., 1., 0.],
                          [0., 0., 0., _np.exp(-1j * float(theta[0]))]], complex)

    @classmethod
    def _from_nice_serialization(cls, state):
        return super(Gczr, cls)._from_nice_serialization(state)


def internal_gate_unitaries():
    """
    The unitaries for the *internally* defined gates.

    These are gates that are used in some circuit-compilation methods internally (e.g.,
    compiling multi-qubit Clifford gates), and under normal usage of functions/methods
    that internally make use of these labels, circuits containing these gate names will
    not be returned to the user -- they are first converted into gates with user-defined
    names and actions (with names starting with 'G').

    Note that some unitaries in this dict do not have unique names. E.g., the key 'I' is the
    1-qubit identity unitary, but so is 'C0' (which refers to the zeroth element of the 1-qubit
    Clifford group).

    Returns
    -------
    dict of numpy.ndarray objects that are complex, unitary matrices.
    """
    std_unitaries = {}
    # The 1-qubit Paulis
    std_unitaries['I'] = _np.array([[1, 0], [0, 1]], complex)
    std_unitaries['X'] = _np.array([[0, 1], [1, 0]], complex)
    std_unitaries['Y'] = _np.array([[0, -1.0j], [1.0j, 0]], complex)
    std_unitaries['Z'] = _np.array([[1, 0], [0, -1]], complex)
    # 5 gates constructed from Hadamard and Phase which each represent 1 of the 5 1-qubit Clifford gate classes
    # that cannot be converted to each other or the identity via Pauli operators.
    std_unitaries['H'] = (1 / _np.sqrt(2)) * _np.array([[1., 1.], [1., -1.]], complex)
    std_unitaries['P'] = _np.array([[1., 0.], [0., 1j]], complex)
    std_unitaries['HP'] = _np.dot(std_unitaries['H'], std_unitaries['P'])
    std_unitaries['PH'] = _np.dot(std_unitaries['P'], std_unitaries['H'])
    std_unitaries['HPH'] = _np.dot(std_unitaries['H'], _np.dot(std_unitaries['P'], std_unitaries['H']))
    # The 1-qubit Clifford group. The labelling is the same as in the the 1-qubit Clifford group generated
    # in pygsti.extras.rb.group, with the mapping 'Ci' - > 'Gci'. (we keep with the convention here of not have
    # hard-coded unitaries starting with a 'G'.)
    std_unitaries['C0'] = _np.array([[1, 0], [0, 1]], complex)
    std_unitaries['C1'] = _np.array([[1, -1j], [1, 1j]], complex) / _np.sqrt(2)
    std_unitaries['C2'] = _np.array([[1, 1], [1j, -1j]], complex) / _np.sqrt(2)
    std_unitaries['C3'] = _np.array([[0, 1], [1, 0]], complex)
    std_unitaries['C4'] = _np.array([[-1, -1j], [1, -1j]], complex) / _np.sqrt(2)
    std_unitaries['C5'] = _np.array([[1, 1], [-1j, 1j]], complex) / _np.sqrt(2)
    std_unitaries['C6'] = _np.array([[0, -1j], [1j, 0]], complex)
    std_unitaries['C7'] = _np.array([[1j, 1], [-1j, 1]], complex) / _np.sqrt(2)
    std_unitaries['C8'] = _np.array([[1j, -1j], [1, 1]], complex) / _np.sqrt(2)
    std_unitaries['C9'] = _np.array([[1, 0], [0, -1]], complex)
    std_unitaries['C10'] = _np.array([[1, 1j], [1, -1j]], complex) / _np.sqrt(2)
    std_unitaries['C11'] = _np.array([[1, -1], [1j, 1j]], complex) / _np.sqrt(2)
    std_unitaries['C12'] = _np.array([[1, 1], [1, -1]], complex) / _np.sqrt(2)
    std_unitaries['C13'] = _np.array([[0.5 - 0.5j, 0.5 + 0.5j], [0.5 + 0.5j, 0.5 - 0.5j]], complex)
    std_unitaries['C14'] = _np.array([[1, 0], [0, 1j]], complex)
    std_unitaries['C15'] = _np.array([[1, 1], [-1, 1]], complex) / _np.sqrt(2)
    std_unitaries['C16'] = _np.array([[0.5 + 0.5j, 0.5 - 0.5j], [0.5 - 0.5j, 0.5 + 0.5j]], complex)
    std_unitaries['C17'] = _np.array([[0, 1], [1j, 0]], complex)
    std_unitaries['C18'] = _np.array([[1j, -1j], [-1j, -1j]], complex) / _np.sqrt(2)
    std_unitaries['C19'] = _np.array([[0.5 + 0.5j, -0.5 + 0.5j], [0.5 - 0.5j, -0.5 - 0.5j]], complex)
    std_unitaries['C20'] = _np.array([[0, -1j], [-1, 0]], complex)
    std_unitaries['C21'] = _np.array([[1, -1], [1, 1]], complex) / _np.sqrt(2)
    std_unitaries['C22'] = _np.array([[0.5 + 0.5j, 0.5 - 0.5j], [-0.5 + 0.5j, -0.5 - 0.5j]], complex)
    std_unitaries['C23'] = _np.array([[1, 0], [0, -1j]], complex)
    # Standard 2-qubit gates.
    std_unitaries['CPHASE'] = _np.array([[1., 0., 0., 0.], [0., 1., 0., 0.], [
                                        0., 0., 1., 0.], [0., 0., 0., -1.]], complex)
    std_unitaries['CNOT'] = _np.array([[1., 0., 0., 0.], [0., 1., 0., 0.], [0., 0., 0., 1.], [0., 0., 1., 0.]], complex)
    std_unitaries['SWAP'] = _np.array([[1., 0., 0., 0.], [0., 0., 1., 0.], [0., 1., 0., 0.], [0., 0., 0., 1.]], complex)

    return std_unitaries


def is_gate_this_standard_unitary(gate_unitary, standard_gate_name):
    """
    Whether a unitary is, up to a phase, the standard gate specified by the name `standard_gate_name`.

    The correspondence between the standard names and unitaries is w.r.t the
    internally-used gatenames (see internal_gate_unitaries()).  For example, one use
    of this function is to check whether some gate specifed by a user with the name
    'Ghadamard' is the Hadamard gate, denoted internally by 'H'.

    Parameters
    ----------
    gate_unitary : complex np.array
        The unitary to test.

    standard_gate_name : str
        The standard gatename to check whether the unitary `gate_unitary` is (e.g., 'CNOT').

    Returns
    -------
    bool
        True if the `gate_unitary` is, up to phase, the unitary specified `standard_gate_name`.
        False otherwise.
    """
    std_unitaries = internal_gate_unitaries()
    if _np.shape(gate_unitary) != _np.shape(std_unitaries[standard_gate_name]):
        return False
    else:
        pm_input = _ot.unitary_to_pauligate(gate_unitary)
        pm_std = _ot.unitary_to_pauligate(std_unitaries[standard_gate_name])
        equal = _np.allclose(pm_input, pm_std)
        return equal


# Currently not needed, but might be added in.
#


def is_gate_pauli_equivalent_to_this_standard_unitary(gate_unitary, standard_gate_name):
    """
    Whether a unitary is the standard gate specified by `standard_gate_name`.

    This equivalence is tested up to pre- and post-multiplication by some Pauli and up to
    a phase, The correspondence between the standard names and unitaries is w.r.t the
    internally-used gatenames (see internal_gate_unitaries()).

    Currently only supported for Clifford gates.

    Parameters
    ----------
    gate_unitary : complex np.array
        The unitary to test.

    standard_gate_name : str
        The standard gatename to check whether the unitary `gate_unitary` is (e.g., 'CNOT').

    Returns
    -------
    bool
        True if the `gate_unitary` is, up to phase and Pauli-multiplication, the unitary
        specified `standard_gate_name`. False otherwise.
    """
    std_symplectic_reps = _symp.compute_internal_gate_symplectic_representations()
    gate_symplectic_rep = _symp.unitary_to_symplectic(gate_unitary)

    if _np.shape(gate_symplectic_rep[0]) != _np.shape(std_symplectic_reps[standard_gate_name][0]):
        return False
    else:
        return _np.allclose(gate_symplectic_rep[0], std_symplectic_reps[standard_gate_name][0])


def standard_gatename_unitaries():
    """
    Constructs and returns a dictionary of unitary matrices describing the action of "standard" gates.

    These gates (the keys of the returned dictionary) are:

    - Clifford Gates:

      - 'Gi' : the 1Q idle operation.
      - 'Gxpi','Gypi','Gzpi' : 1Q pi rotations around X, Y and Z.
      - 'Gxpi2','Gypi2','Gzpi2' : 1Q pi/2 rotations around X, Y and Z.
      - 'Gxmpi2','Gympi2','Gzmpi2' : 1Q -pi/2 rotations around X, Y and Z.
      - 'Gh' : Hadamard.
      - 'Gp', 'Gpdag' : phase and inverse phase (an alternative notation/name for Gzpi and Gzmpi2).
      - 'Gci' where i = 0, 1, ..., 23 : the 24 1-qubit Cliffor gates (all the gates above are included as one of these).
      - 'Gcphase','Gcnot','Gswap' : standard 2Q gates.

    - Non-Clifford gates:

      - 'Gt', 'Gtdag' : the T and inverse T gates (T is a Z rotation by pi/4).
      - 'Gzr' : a parameterized gate that is a Z rotation by an angle, where when the angle = pi then it equals Z.

    Mostly, pyGSTi does not assume that a gate with one of these names is indeed
    the unitary specified here. Instead, these names are intended as short-hand
    for defining ProcessorSpecs and n-qubit models. Moreover, when these names
    are used then conversion of circuits to QUIL or QISKIT is particular convenient,
    and does not require the user to specify the syntax conversion.

    Returns
    -------
    dict of numpy.ndarray objects.
    """
    std_unitaries = {}

    sigmax = _np.array([[0, 1], [1, 0]])
    sigmay = _np.array([[0, -1.0j], [1.0j, 0]])
    sigmaz = _np.array([[1, 0], [0, -1]])

    def u_op(exp):
        return _np.array(_spl.expm(-1j * exp / 2), complex)

    std_unitaries['Gi'] = _np.array([[1., 0.], [0., 1.]], complex)

    std_unitaries['Gxpi2'] = u_op(_np.pi / 2 * sigmax)
    std_unitaries['Gypi2'] = u_op(_np.pi / 2 * sigmay)
    std_unitaries['Gzpi2'] = u_op(_np.pi / 2 * sigmaz)

    std_unitaries['Gxpi'] = _np.array([[0., 1.], [1., 0.]], complex)
    std_unitaries['Gypi'] = _np.array([[0., -1j], [1j, 0.]], complex)
    std_unitaries['Gzpi'] = _np.array([[1., 0.], [0., -1.]], complex)

    std_unitaries['Gxmpi2'] = u_op(-1 * _np.pi / 2 * sigmax)
    std_unitaries['Gympi2'] = u_op(-1 * _np.pi / 2 * sigmay)
    std_unitaries['Gzmpi2'] = u_op(-1 * _np.pi / 2 * sigmaz)

    H = (1 / _np.sqrt(2)) * _np.array([[1., 1.], [1., -1.]], complex)
    P = _np.array([[1., 0.], [0., 1j]], complex)
    Pdag = _np.array([[1., 0.], [0., -1j]], complex)

    std_unitaries['Gh'] = H
    std_unitaries['Gp'] = P
    std_unitaries['Gpdag'] = Pdag
    #std_unitaries['Ghp'] = _np.dot(H,P)
    #std_unitaries['Gph'] = _np.dot(P,H)
    #std_unitaries['Ghph'] = _np.dot(H,_np.dot(P,H))
    std_unitaries['Gt'] = _np.array([[1., 0.], [0., _np.exp(1j * _np.pi / 4)]], complex)
    std_unitaries['Gtdag'] = _np.array([[1., 0.], [0., _np.exp(-1j * _np.pi / 4)]], complex)
    # The 1-qubit Clifford group. The labelling is the same as in the the 1-qubit Clifford group generated
    # in pygsti.extras.rb.group, and also in the internal standard unitary (but with 'Gci' -> 'Ci')
    std_unitaries['Gc0'] = _np.array([[1, 0], [0, 1]], complex)  # This is Gi
    std_unitaries['Gc1'] = _np.array([[1, -1j], [1, 1j]], complex) / _np.sqrt(2)
    std_unitaries['Gc2'] = _np.array([[1, 1], [1j, -1j]], complex) / _np.sqrt(2)
    std_unitaries['Gc3'] = _np.array([[0, 1], [1, 0]], complex)  # This is Gxpi (up to phase)
    std_unitaries['Gc4'] = _np.array([[-1, -1j], [1, -1j]], complex) / _np.sqrt(2)
    std_unitaries['Gc5'] = _np.array([[1, 1], [-1j, 1j]], complex) / _np.sqrt(2)
    std_unitaries['Gc6'] = _np.array([[0, -1j], [1j, 0]], complex)  # This is Gypi (up to phase)
    std_unitaries['Gc7'] = _np.array([[1j, 1], [-1j, 1]], complex) / _np.sqrt(2)
    std_unitaries['Gc8'] = _np.array([[1j, -1j], [1, 1]], complex) / _np.sqrt(2)
    std_unitaries['Gc9'] = _np.array([[1, 0], [0, -1]], complex)  # This is Gzpi
    std_unitaries['Gc10'] = _np.array([[1, 1j], [1, -1j]], complex) / _np.sqrt(2)
    std_unitaries['Gc11'] = _np.array([[1, -1], [1j, 1j]], complex) / _np.sqrt(2)
    std_unitaries['Gc12'] = _np.array([[1, 1], [1, -1]], complex) / _np.sqrt(2)  # This is Gh
    std_unitaries['Gc13'] = _np.array([[0.5 - 0.5j, 0.5 + 0.5j], [0.5 + 0.5j, 0.5 - 0.5j]],
                                      complex)  # This is Gxmpi2 (up to phase)
    std_unitaries['Gc14'] = _np.array([[1, 0], [0, 1j]], complex)  # THis is Gzpi2 / Gp (up to phase)
    std_unitaries['Gc15'] = _np.array([[1, 1], [-1, 1]], complex) / _np.sqrt(2)  # This is Gympi2 (up to phase)
    std_unitaries['Gc16'] = _np.array([[0.5 + 0.5j, 0.5 - 0.5j], [0.5 - 0.5j, 0.5 + 0.5j]],
                                      complex)  # This is Gxpi2 (up to phase)
    std_unitaries['Gc17'] = _np.array([[0, 1], [1j, 0]], complex)
    std_unitaries['Gc18'] = _np.array([[1j, -1j], [-1j, -1j]], complex) / _np.sqrt(2)
    std_unitaries['Gc19'] = _np.array([[0.5 + 0.5j, -0.5 + 0.5j], [0.5 - 0.5j, -0.5 - 0.5j]], complex)
    std_unitaries['Gc20'] = _np.array([[0, -1j], [-1, 0]], complex)
    std_unitaries['Gc21'] = _np.array([[1, -1], [1, 1]], complex) / _np.sqrt(2)  # This is Gypi2 (up to phase)
    std_unitaries['Gc22'] = _np.array([[0.5 + 0.5j, 0.5 - 0.5j], [-0.5 + 0.5j, -0.5 - 0.5j]], complex)
    std_unitaries['Gc23'] = _np.array([[1, 0], [0, -1j]], complex)  # This is Gzmpi2 / Gpdag (up to phase)
    # Two-qubit gates
    std_unitaries['Gcphase'] = _np.array([[1., 0., 0., 0.], [0., 1., 0., 0.], [
                                         0., 0., 1., 0.], [0., 0., 0., -1.]], complex)
    std_unitaries['Gcnot'] = _np.array([[1., 0., 0., 0.], [0., 1., 0., 0.], [
                                       0., 0., 0., 1.], [0., 0., 1., 0.]], complex)
    std_unitaries['Gswap'] = _np.array([[1., 0., 0., 0.], [0., 0., 1., 0.], [
                                       0., 1., 0., 0.], [0., 0., 0., 1.]], complex)

    std_unitaries['Gzr'] = Gzr()
    std_unitaries['Gczr'] = Gczr()

    #Add these at the end, since we don't want unitary_to_standard_gatenemt to return these "shorthand" names
    std_unitaries['Gx'] = std_unitaries['Gxpi2']
    std_unitaries['Gy'] = std_unitaries['Gypi2']
    std_unitaries['Gz'] = std_unitaries['Gzpi2']

    return std_unitaries


def unitary_to_standard_gatename(unitary):
    """
    Looks up and returns the standard gate name for a unitary gate matrix, if one exists.

    Parameters
    ----------
    unitary : complex np.array
        The unitary to convert.

    Returns
    -------
    str or None
        If `gate_unitary` matches a standard gate, the standard name of this gate (a
        key in the dictionary given by :function:`standard_gatename_unitaries`).  `None` otherwise.
    """
    for std_name, U in standard_gatename_unitaries().items():
        if not callable(U) and not callable(unitary) and U.shape == unitary.shape and _np.allclose(unitary, U):
            return std_name
    return None


def standard_gatenames_cirq_conversions():
    """
    A dictionary converting the gates with standard names to the cirq names for these gates.

    See :function:`standard_gatename_unitaries`.

    By default, an idle operation will not be converted to a gate.
    If you want an idle to be converted to a `cirq.WaitGate`, you will have
    to modify this dictionary.

    Note that throughout pyGSTi the standard gatenames (e.g., 'Gh' for Hadamard)
    are not enforced to correspond to the expected unitaries. So, if the user
    as, say, defined 'Gh' to be something other than the Hadamard gate this
    conversion dictionary will be incorrect.

    Currently there are some standard gate names with no conversion to cirq.

    TODO: add Clifford gates with
    https://cirq.readthedocs.io/en/latest/generated/cirq.SingleQubitCliffordGate.html

    Returns
    -------
    dict mapping strings to string
    """
    try:
        import cirq
    except ImportError:
        raise ImportError("Cirq is required for this operation, and it does not appear to be installed.")

    std_gatenames_to_cirq = {}
    std_gatenames_to_cirq['Gi'] = None
    std_gatenames_to_cirq['Gxpi2'] = cirq.XPowGate(exponent=1 / 2)
    std_gatenames_to_cirq['Gxmpi2'] = cirq.XPowGate(exponent=-1 / 2)
    std_gatenames_to_cirq['Gxpi'] = cirq.X
    std_gatenames_to_cirq['Gzpi2'] = cirq.ZPowGate(exponent=1 / 2)
    std_gatenames_to_cirq['Gzmpi2'] = cirq.ZPowGate(exponent=-1 / 2)
    std_gatenames_to_cirq['Gzpi'] = cirq.Z
    std_gatenames_to_cirq['Gypi2'] = cirq.YPowGate(exponent=1 / 2)
    std_gatenames_to_cirq['Gympi2'] = cirq.YPowGate(exponent=-1 / 2)
    std_gatenames_to_cirq['Gypi'] = cirq.Y
    std_gatenames_to_cirq['Gp'] = std_gatenames_to_cirq['Gzpi2']
    std_gatenames_to_cirq['Gpdag'] = std_gatenames_to_cirq['Gzmpi2']
    std_gatenames_to_cirq['Gh'] = cirq.H
    std_gatenames_to_cirq['Gt'] = cirq.T
    std_gatenames_to_cirq['Gtdag'] = cirq.T**-1
    std_gatenames_to_cirq['Gcphase'] = cirq.CZ
    std_gatenames_to_cirq['Gcnot'] = cirq.CNOT
    std_gatenames_to_cirq['Gswap'] = cirq.SWAP

    return std_gatenames_to_cirq


def standard_gatenames_quil_conversions():
    """
    A dictionary converting the gates with standard names to the QUIL names for these gates.

    See :function:`standard_gatename_unitaries`.

    Note that throughout pyGSTi the standard gatenames (e.g., 'Gh' for Hadamard)
    are not enforced to correspond to the expected unitaries. So, if the user
    as, say, defined 'Gh' to be something other than the Hadamard gate this
    conversion dictionary will be incorrect.

    Currently there are some standard gate names with no conversion to quil.

    Returns
    -------
    dict mapping strings to strings.
    """
    std_gatenames_to_quil = {}
    std_gatenames_to_quil['Gi'] = 'I'
    std_gatenames_to_quil['Gxpi2'] = 'RX(pi/2)'
    std_gatenames_to_quil['Gxmpi2'] = 'RX(-pi/2)'
    std_gatenames_to_quil['Gxpi'] = 'X'
    std_gatenames_to_quil['Gzpi2'] = 'RZ(pi/2)'
    std_gatenames_to_quil['Gzmpi2'] = 'RZ(-pi/2)'
    std_gatenames_to_quil['Gzpi'] = 'Z'
    std_gatenames_to_quil['Gypi2'] = 'RY(pi/2)'
    std_gatenames_to_quil['Gympi2'] = 'RY(-pi/2)'
    std_gatenames_to_quil['Gypi'] = 'Y'
    std_gatenames_to_quil['Gp'] = 'RZ(pi/2)'  # todo : check that this is correct, and shouldn't instead be -pi/2
    std_gatenames_to_quil['Gpdag'] = 'RZ(-pi/2)'  # todo : check that this is correct, and shouldn't instead be +pi/2
    std_gatenames_to_quil['Gh'] = 'H'
    std_gatenames_to_quil['Gt'] = 'RZ(pi/4)'  # todo : check that this is correct, and shouldn't instead be -pi/4
    std_gatenames_to_quil['Gtdag'] = 'RZ(-pi/4)'  # todo : check that this is correct, and shouldn't instead be +pi/4
    std_gatenames_to_quil['Gcphase'] = 'CZ'
    std_gatenames_to_quil['Gcnot'] = 'CNOT'

    std_gatenames_to_quil['Gc0'] = 'Gc0'
    std_gatenames_to_quil['Gc1'] = 'Gc1'
    std_gatenames_to_quil['Gc2'] = 'Gc2'
    std_gatenames_to_quil['Gc3'] = 'Gc3'
    std_gatenames_to_quil['Gc4'] = 'Gc4'
    std_gatenames_to_quil['Gc5'] = 'Gc5'
    std_gatenames_to_quil['Gc6'] = 'Gc6'
    std_gatenames_to_quil['Gc7'] = 'Gc7'
    std_gatenames_to_quil['Gc8'] = 'Gc8'
    std_gatenames_to_quil['Gc9'] = 'Gc9'
    std_gatenames_to_quil['Gc10'] = 'Gc10'
    std_gatenames_to_quil['Gc11'] = 'Gc11'
    std_gatenames_to_quil['Gc12'] = 'Gc12'
    std_gatenames_to_quil['Gc13'] = 'Gc13'
    std_gatenames_to_quil['Gc14'] = 'Gc14'
    std_gatenames_to_quil['Gc15'] = 'Gc15'
    std_gatenames_to_quil['Gc16'] = 'Gc16'
    std_gatenames_to_quil['Gc17'] = 'Gc17'
    std_gatenames_to_quil['Gc18'] = 'Gc18'
    std_gatenames_to_quil['Gc19'] = 'Gc19'
    std_gatenames_to_quil['Gc20'] = 'Gc20'
    std_gatenames_to_quil['Gc21'] = 'Gc21'
    std_gatenames_to_quil['Gc22'] = 'Gc22'
    std_gatenames_to_quil['Gc23'] = 'Gc23'

    return std_gatenames_to_quil


def standard_gatenames_chp_conversions():
    """
    A dictionary converting the gates with standard names to CHP native operations.

    See :function:`standard_gatename_unitaries`.

    Note that the native operations are assumed to act on qubit 0 or qubits 0 and 1,
    depending on whether it is a one-qubit or two-qubit operation. It is recommended
    to use ComposedOp and EmbeddedOp to get compositions/different target qubits
    for CHP operations.

    Note that throughout pyGSTi the standard gatenames (e.g., 'Gh' for Hadamard)
    are not enforced to correspond to the expected unitaries. So, if the user
    as, say, defined 'Gh' to be something other than the Hadamard gate this
    conversion dictionary will be incorrect.

    Returns
    -------
    dict mapping strings to string
    """
    std_gatenames_to_chp = {}

    # Native gates for CHP
    std_gatenames_to_chp['h'] = ['h 0']
    std_gatenames_to_chp['p'] = ['p 0']
    std_gatenames_to_chp['c'] = ['c 0 1']
    std_gatenames_to_chp['m'] = ['m 0']

    # Cliffords
    std_gatenames_to_chp['Gc0'] = []
    std_gatenames_to_chp['Gc1'] = ['h 0', 'p 0', 'h 0', 'p 0']
    std_gatenames_to_chp['Gc2'] = ['h 0', 'p 0']
    std_gatenames_to_chp['Gc3'] = ['h 0', 'p 0', 'p 0', 'h 0']
    std_gatenames_to_chp['Gc4'] = ['p 0', 'h 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gc5'] = ['h 0', 'p 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gc6'] = ['h 0', 'p 0', 'p 0', 'h 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gc7'] = ['h 0', 'p 0', 'h 0', 'p 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gc8'] = ['h 0', 'p 0', 'h 0', 'p 0', 'p 0', 'h 0']
    std_gatenames_to_chp['Gc9'] = ['p 0', 'p 0']
    std_gatenames_to_chp['Gc10'] = ['p 0', 'h 0']
    std_gatenames_to_chp['Gc11'] = ['p 0', 'p 0', 'h 0', 'p 0']
    std_gatenames_to_chp['Gc12'] = ['h 0']
    std_gatenames_to_chp['Gc13'] = ['p 0', 'h 0', 'p 0']
    std_gatenames_to_chp['Gc14'] = ['p 0']
    std_gatenames_to_chp['Gc15'] = ['h 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gc16'] = ['h 0', 'p 0', 'h 0']
    std_gatenames_to_chp['Gc17'] = ['h 0', 'p 0', 'p 0', 'h 0', 'p 0']
    std_gatenames_to_chp['Gc18'] = ['p 0', 'p 0', 'h 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gc19'] = ['p 0', 'h 0', 'p 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gc20'] = ['p 0', 'h 0', 'p 0', 'p 0', 'h 0']
    std_gatenames_to_chp['Gc21'] = ['p 0', 'p 0', 'h 0']
    std_gatenames_to_chp['Gc22'] = ['h 0', 'p 0', 'h 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gc23'] = ['p 0', 'p 0', 'p 0']

    std_gatenames_to_chp['Gcnot'] = ['c 0 1']
    std_gatenames_to_chp['Gcphase'] = ['h 0', 'c 0 1', 'h 0']

    # Standard names
    std_gatenames_to_chp['Gi'] = []

    std_gatenames_to_chp['Gxpi'] = ['h 0', 'p 0', 'p 0', 'h 0']
    # Shorter Y compilation is possible, up to global phase: p, p, h, p, p, h = ZX = iY
    std_gatenames_to_chp['Gypi'] = ['p 0', 'h 0', 'p 0', 'p 0', 'h 0', 'p 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gzpi'] = ['p 0', 'p 0']

    std_gatenames_to_chp['Gxpi2'] = ['h 0', 'p 0', 'h 0']
    std_gatenames_to_chp['Gypi2'] = ['p 0', 'h 0', 'p 0', 'h 0', 'p 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gzpi2'] = ['p 0']

    std_gatenames_to_chp['Gxmpi2'] = ['h 0', 'p 0', 'p 0', 'p 0', 'h 0']
    std_gatenames_to_chp['Gympi2'] = ['p 0', 'h 0', 'p 0', 'p 0', 'p 0', 'h 0', 'p 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gzmpi2'] = ['p 0', 'p 0', 'p 0']

    std_gatenames_to_chp['Gh'] = ['h 0']
    std_gatenames_to_chp['Gp'] = ['p 0']
    std_gatenames_to_chp['Gpdag'] = ['p 0', 'p 0', 'p 0']

    std_gatenames_to_chp['Gx'] = ['h 0', 'p 0', 'h 0']
    std_gatenames_to_chp['Gy'] = ['p 0', 'h 0', 'p 0', 'h 0', 'p 0', 'p 0', 'p 0']
    std_gatenames_to_chp['Gz'] = ['p 0']

    return std_gatenames_to_chp


def standard_gatenames_openqasm_conversions(version='u3'):
    """
    A dictionary converting the gates with standard names to the QASM names for these gates.

    See :function:`standard_gatename_unitaries`.

    Note that throughout pyGSTi the standard gatenames (e.g., 'Gh' for Hadamard)
    are not enforced to correspond to the expected unitaries. So, if the user
    has, say, defined 'Gh' to be something other than the Hadamard gate this
    conversion dictionary will be incorrect.

    Parameters
    ----------
    version : string, optional
        Either 'u3' or 'x-sx-rz'. Specifies the naming convention for the QASM
        gates. With 'u3', all single-qubit gates are specified in terms of the
        'u3' gate, used by IBM and QisKit until ~2021 (see the qasm_u3 function).
        With 'x-sx-rz', all single-gates are specified in terms of 'x' (an x pi
        rotation), 'sx' (an x pi/2 rotation) and 'rz' (a parameterized rotation
        around z by an angle theta).

    Returns
    -------
    dict
        mapping strings (representing pyGSTi standard gate names) to list of strings
        (representing QASM gate names).

    dict
        mapping strings (representing pyGSTi standard gate names) to functions
        that map the parameters of a pyGSTi gate to a string to be combined
        with the QASM name to specify the specific gate, in QASM.
    """
    if version == 'u3':
        std_gatenames_to_qasm = {}
        std_gatenames_to_qasm['Gi'] = ['id']
        std_gatenames_to_qasm['Gxpi2'] = ['u3(1.570796326794897, 4.71238898038469, 1.570796326794897)']  # [1,3,1]*pi/2
        std_gatenames_to_qasm['Gxmpi2'] = ['u3(1.570796326794897, 1.570796326794897, 4.71238898038469)']  # [1,1,3]*pi/2
        std_gatenames_to_qasm['Gxpi'] = ['x']
        std_gatenames_to_qasm['Gzpi2'] = ['u3(0, 0, 1.570796326794897)']  # [0, 0, 1] * pi/2
        std_gatenames_to_qasm['Gzmpi2'] = ['u3(0, 0, 4.71238898038469)']  # [0, 0, 3] * pi/2
        std_gatenames_to_qasm['Gzpi'] = ['z']
        std_gatenames_to_qasm['Gypi2'] = ['u3(1.570796326794897, 0, 0)']  # [1, 0, 0] * pi/2
        std_gatenames_to_qasm['Gympi2'] = ['u3(1.570796326794897, 3.141592653589793, 3.141592653589793)']  # [1,2,2]pi/2
        std_gatenames_to_qasm['Gypi'] = ['y']
        std_gatenames_to_qasm['Gp'] = ['s']
        std_gatenames_to_qasm['Gpdag'] = ['sdg']
        std_gatenames_to_qasm['Gh'] = ['h']
        std_gatenames_to_qasm['Gt'] = ['t']
        std_gatenames_to_qasm['Gtdag'] = ['tdg']
        std_gatenames_to_qasm['Gcphase'] = ['cz']
        std_gatenames_to_qasm['Gcnot'] = ['cx']
        std_gatenames_to_qasm['Gswap'] = ['swap']
        std_gatenames_to_qasm['Gc0'] = ['u3(0, 0, 0)']  # [0, 0, 0] * pi/2 (thi is Gi)
        std_gatenames_to_qasm['Gc1'] = ['u3(1.570796326794897, 0, 1.570796326794897)']  # [1, 0, 1] * pi/2
        std_gatenames_to_qasm['Gc2'] = ['u3(1.570796326794897, 1.570796326794897, 3.141592653589793)']  # [1, 1, 2]*pi/2
        std_gatenames_to_qasm['Gc3'] = ['u3(3.141592653589793, 0, 3.141592653589793)']  # [2, 0, 2] * pi/2 (= Gxpi)
        std_gatenames_to_qasm['Gc4'] = ['u3(1.570796326794897, 3.141592653589793, 4.71238898038469)']  # [1, 2, 3]*pi/2
        std_gatenames_to_qasm['Gc5'] = ['u3(1.570796326794897, 4.71238898038469, 3.141592653589793)']  # [1, 3, 2]*pi/2
        std_gatenames_to_qasm['Gc6'] = ['u3(3.141592653589793, 0, 0)']  # [2, 0, 0] * pi/2 (this is Gypi)
        std_gatenames_to_qasm['Gc7'] = ['u3(1.570796326794897, 3.141592653589793, 1.570796326794897)']  # [1, 2, 1]*pi/2
        std_gatenames_to_qasm['Gc8'] = ['u3(1.570796326794897, 4.71238898038469, 0.)']  # [1, 3, 0] * pi/2
        std_gatenames_to_qasm['Gc9'] = ['u3(0, 0, 3.141592653589793)']  # [0, 0, 2] * pi/2 (this is Gzpi)
        std_gatenames_to_qasm['Gc10'] = ['u3(1.570796326794897, 0, 4.71238898038469)']  # [1, 0, 3] * pi/2
        std_gatenames_to_qasm['Gc11'] = ['u3(1.570796326794897, 1.570796326794897, 0.)']  # [1, 1, 0] * pi/2
        std_gatenames_to_qasm['Gc12'] = ['u3(1.570796326794897, 0., 3.141592653589793)']  # [1, 0, 2] * pi/2 (= Gh)
        # [1, 1, 3] * pi/2 (this is Gxmpi2 )
        std_gatenames_to_qasm['Gc13'] = ['u3(1.570796326794897, 1.570796326794897, 4.71238898038469)']
        std_gatenames_to_qasm['Gc14'] = ['u3(0, 0, 1.570796326794897)']  # [0, 0, 1] * pi/2 (this is Gzpi2 / Gp)
        # [1, 2, 2] * pi/2 (the is Gympi2)
        std_gatenames_to_qasm['Gc15'] = ['u3(1.570796326794897, 3.141592653589793, 3.141592653589793)']
        # [1, 3, 1] * pi/2 (this is Gxpi2 )
        std_gatenames_to_qasm['Gc16'] = ['u3(1.570796326794897, 4.71238898038469, 1.570796326794897)']
        std_gatenames_to_qasm['Gc17'] = ['u3(3.141592653589793, 0, 1.570796326794897)']  # [2, 0, 1] * pi/2
        std_gatenames_to_qasm['Gc18'] = ['u3(1.570796326794897, 3.141592653589793, 0.)']  # [1, 2, 0] * pi/2
        std_gatenames_to_qasm['Gc19'] = ['u3(1.570796326794897, 4.71238898038469, 4.71238898038469)']  # [1, 3, 3]*pi/2
        std_gatenames_to_qasm['Gc20'] = ['u3(3.141592653589793, 0, 4.71238898038469)']  # [2, 0, 3] * pi/2
        std_gatenames_to_qasm['Gc21'] = ['u3(1.570796326794897, 0, 0)']  # [1, 0, 0] * pi/2 (this is Gypi2)
        std_gatenames_to_qasm['Gc22'] = ['u3(1.570796326794897, 1.570796326794897, 1.570796326794897)']  # [1,1,1]*pi/2
        std_gatenames_to_qasm['Gc23'] = ['u3(0, 0, 4.71238898038469)']  # [0, 0, 3] * pi/2 (this is Gzmpi2 / Gpdag)

        std_gatenames_to_argmap = {}
        std_gatenames_to_argmap['Gzr'] = lambda gatearg: ['u3(0, 0, ' + str(gatearg[0]) + ')']
        std_gatenames_to_argmap['Gczr'] = lambda gatearg: ['crz(' + str(gatearg[0]) + ')']
        std_gatenames_to_argmap['Gu3'] = lambda gatearg: ['u3(' + str(gatearg[0]) + ', '
                                                          + str(gatearg[1]) + ', ' + str(gatearg[2]) + ')']

    elif version == 'x-sx-rz':
        std_gatenames_to_qasm = {}
        std_gatenames_to_qasm['Gcphase'] = ['cz']
        std_gatenames_to_qasm['Gcnot'] = ['cx']
        std_gatenames_to_qasm['Gi'] = ['rz(0.)']
        std_gatenames_to_qasm['Gx'] = ['sx']
        std_gatenames_to_qasm['Gxpi2'] = ['sx']
        std_gatenames_to_qasm['Gy'] = ['rz(4.71238898038469)', 'sx', 'rz(1.570796326794897)']
        std_gatenames_to_qasm['Gypi2'] = ['rz(4.71238898038469)', 'sx', 'rz(1.570796326794897)']
        std_gatenames_to_qasm['Gz'] = ['rz(1.570796326794897)']
        std_gatenames_to_qasm['Gzpi2'] = ['rz(1.570796326794897)']
        std_gatenames_to_qasm['Gxpi'] = ['x']
        std_gatenames_to_qasm['Gypi'] = ['rz(3.141592653589793)', 'x']
        std_gatenames_to_qasm['Gzpi'] = ['rz(3.141592653589793)']
        std_gatenames_to_qasm['Gxmpi2'] = ['sx', 'x']
        std_gatenames_to_qasm['Gympi2'] = ['rz(1.570796326794897)', 'sx', 'rz(4.71238898038469)']
        std_gatenames_to_qasm['Gzmpi2'] = ['rz(4.71238898038469)']
        std_gatenames_to_qasm['Gh'] = ['rz(1.570796326794897)', 'sx', 'rz(1.570796326794897)']
        std_gatenames_to_qasm['Gp'] = ['rz(1.570796326794897)']
        std_gatenames_to_qasm['Gpdag'] = ['rz(4.71238898038469)']
        std_gatenames_to_qasm['Gc0'] = ['rz(0.)']
        std_gatenames_to_qasm['Gc1'] = ['sx', 'rz(1.570796326794897)']
        std_gatenames_to_qasm['Gc2'] = ['rz(1.570796326794897)', 'sx', 'rz(3.141592653589793)']
        std_gatenames_to_qasm['Gc3'] = ['x']
        std_gatenames_to_qasm['Gc4'] = ['rz(3.141592653589793)', 'sx', 'rz(4.71238898038469)']
        std_gatenames_to_qasm['Gc5'] = ['rz(1.570796326794897)', 'sx']
        std_gatenames_to_qasm['Gc6'] = ['rz(3.141592653589793)', 'x']
        std_gatenames_to_qasm['Gc7'] = ['sx', 'rz(4.71238898038469)']
        std_gatenames_to_qasm['Gc8'] = ['rz(4.71238898038469)', 'sx']
        std_gatenames_to_qasm['Gc9'] = ['rz(3.141592653589793)']
        std_gatenames_to_qasm['Gc10'] = ['rz(3.141592653589793)', 'sx', 'rz(1.570796326794897)']
        std_gatenames_to_qasm['Gc11'] = ['rz(1.570796326794897)', 'sx', 'x']
        std_gatenames_to_qasm['Gc12'] = ['rz(1.570796326794897)', 'sx', 'rz(1.570796326794897)']
        std_gatenames_to_qasm['Gc13'] = ['sx', 'x']
        std_gatenames_to_qasm['Gc14'] = ['rz(1.570796326794897)']
        std_gatenames_to_qasm['Gc15'] = ['rz(1.570796326794897)', 'sx', 'rz(4.71238898038469)']
        std_gatenames_to_qasm['Gc16'] = ['sx']
        std_gatenames_to_qasm['Gc17'] = ['rz(4.71238898038469)', 'x']
        std_gatenames_to_qasm['Gc18'] = ['rz(4.71238898038469)', 'sx', 'rz(4.71238898038469)']
        std_gatenames_to_qasm['Gc19'] = ['rz(3.141592653589793)', 'sx']
        std_gatenames_to_qasm['Gc20'] = ['rz(1.570796326794897)', 'x']
        std_gatenames_to_qasm['Gc21'] = ['rz(4.71238898038469)', 'sx', 'rz(1.570796326794897)']
        std_gatenames_to_qasm['Gc22'] = ['sx', 'rz(3.141592653589793)']
        std_gatenames_to_qasm['Gc23'] = ['rz(4.71238898038469)']
        std_gatenames_to_qasm['Gt'] = ['rz(0.7853981633974485)']
        std_gatenames_to_qasm['Gtdag'] = ['rz(5.497787143782138)']

        std_gatenames_to_argmap = {}
        std_gatenames_to_argmap['Gzr'] = lambda gatearg: ['rz(' + str(gatearg[0]) + ')']
        std_gatenames_to_argmap['Gczr'] = lambda gatearg: ['crz(' + str(gatearg[0]) + ')']
        std_gatenames_to_argmap['Gu3'] = lambda gatearg: ['rz(' + str(gatearg[2]) + ')', 'sx',
                                                          'rz(' + str(float(gatearg[0]) + _np.pi) + ')', 'sx',
                                                          'rz(' + str(float(gatearg[1]) + _np.pi) + ')']
    else:
        raise ValueError("Unknown version!")

    return std_gatenames_to_qasm, std_gatenames_to_argmap


def qasm_u3(theta, phi, lamb, output='unitary'):
    """
    The u3 1-qubit gate of QASM, returned as a unitary.

    if output = 'unitary' and as a processmatrix in the Pauli basis if out = 'superoperator.'

    Parameters
    ----------
    theta : float
        The theta parameter of the u3 gate.

    phi : float
        The phi parameter of the u3 gate.

    lamb : float
        The lambda parameter of the u3 gate.

    output : {'unitary', 'superoperator'}
        Whether the returned value is a unitary matrix or the Pauli-transfer-matrix
        superoperator representing that unitary action.

    Returns
    -------
    numpy.ndarray
    """
    u3_unitary = _np.array([[_np.cos(theta / 2), -1 * _np.exp(1j * lamb) * _np.sin(theta / 2)],
                            [_np.exp(1j * phi) * _np.sin(theta / 2), _np.exp(1j * (lamb + phi)) * _np.cos(theta / 2)]])

    if output == 'unitary':
        return u3_unitary

    elif output == 'superoperator':
        u3_superoperator = _ot.unitary_to_pauligate(u3_unitary)
        return u3_superoperator

    else: raise ValueError("The `output` string is invalid!")