pygsti.tools.internalgates

The standard unitaries and gate names, used internal compilers and short-hand model init

Module Contents

Classes

Gzr	A convenient base class for building serializable "functions" for unitary gate matrices.
Gczr	A convenient base class for building serializable "functions" for unitary gate matrices.

Functions

internal_gate_unitaries()	The unitaries for the internally defined gates.
is_gate_this_standard_unitary(gate_unitary, ...)	Whether a unitary is, up to a phase, the standard gate specified by the name standard_gate_name.
is_gate_pauli_equivalent_to_this_standard_unitary(...)	Whether a unitary is the standard gate specified by standard_gate_name.
standard_gatename_unitaries()	Constructs and returns a dictionary of unitary matrices describing the action of "standard" gates.
unitary_to_standard_gatename(unitary[, up_to_phase, ...])	Looks up and returns the standard gate name for a unitary gate matrix, if one exists.
standard_gatenames_cirq_conversions()	A dictionary converting the gates with standard names to the cirq names for these gates.
cirq_gatenames_standard_conversions()	A dictionary converting cirq gates to built-in pyGSTi names for these gates.
standard_gatenames_quil_conversions()	A dictionary converting the gates with standard names to the QUIL names for these gates.
standard_gatenames_chp_conversions()	A dictionary converting the gates with standard names to CHP native operations.
standard_gatenames_openqasm_conversions([version])	A dictionary converting the gates with standard names to the QASM names for these gates.
qasm_u3(theta, phi, lamb[, output])	The u3 1-qubit gate of QASM, returned as a unitary.

class pygsti.tools.internalgates.Gzr

Bases: pygsti.baseobjs.unitarygatefunction.UnitaryGateFunction

A convenient base class for building serializable “functions” for unitary gate matrices.

Subclasses that don’t need to initialize any attributes other than shape only need to impliement the __call__ method and declare their shape as either a class or instance variable.

shape = (2, 2)

class pygsti.tools.internalgates.Gczr

Bases: pygsti.baseobjs.unitarygatefunction.UnitaryGateFunction

A convenient base class for building serializable “functions” for unitary gate matrices.

Subclasses that don’t need to initialize any attributes other than shape only need to impliement the __call__ method and declare their shape as either a class or instance variable.

shape = (4, 4)

pygsti.tools.internalgates.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.

pygsti.tools.internalgates.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_unitarycomplex np.array

The unitary to test.

standard_gate_namestr

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.

pygsti.tools.internalgates.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_unitarycomplex np.array

The unitary to test.

standard_gate_namestr

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.

pygsti.tools.internalgates.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 Clifford gates (all the gates above are included as one of these).

  • ‘Gcphase’,’Gcnot’,’Gswap’, ‘Giswap’ : standard 2Q gates.

  • ‘Gsqrtiswap’ : square-root of ISWAP gate, used in some superconducting qubit platforms.

  • ‘Gxx’, ‘Gzz’ : MS-style parity gates

  • ‘Gcres’, ‘Gecres’ : Cross-resonance and echoed cross-resonance gates. Native gate operations common on transmon systems (including IBM).

• 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.

  • ‘Gn’ : N gate, pi/2 rotation about the (np.sqrt(3)/2, 0, -1/2) axis of the Bloch sphere, native gate in some spin qubit systems.

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.

pygsti.tools.internalgates.unitary_to_standard_gatename(unitary, up_to_phase=False, return_phase=False)

Looks up and returns the standard gate name for a unitary gate matrix, if one exists.

Parameters

unitarycomplex np.array

The unitary to convert.

up_to_phasebool, optional (default False)

If true then after checking if the unitary is exactly equivalent to a built-in one, this then checks if the input unitary is equal to to a built-in one up to a global phase.

return_phasebool, optional (default False)

If true, and up_to_phase is true, then if a unitary is equivalent up to a global phase to a built-in one, we return that phase (i.e. the phase the built-in one would need to be multiplied by).

Returns

str or None

If gate_unitary matches a standard gate, the standard name of this gate (a key in the dictionary given by standard_gatename_unitaries()). None otherwise.

pygsti.tools.internalgates.standard_gatenames_cirq_conversions()

A dictionary converting the gates with standard names to the cirq names for these gates.

See 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.

Returns

std_gatenames_to_cirq

dict mapping strings corresponding to standard built-in pyGSTi names to corresponding cirq operation objects.

pygsti.tools.internalgates.cirq_gatenames_standard_conversions()

A dictionary converting cirq gates to built-in pyGSTi names for these gates. Does not currently support conversion of all cirq gate types.

pygsti.tools.internalgates.standard_gatenames_quil_conversions()

A dictionary converting the gates with standard names to the QUIL names for these gates.

See 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.

pygsti.tools.internalgates.standard_gatenames_chp_conversions()

A dictionary converting the gates with standard names to CHP native operations.

See 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

pygsti.tools.internalgates.standard_gatenames_openqasm_conversions(version='u3')

A dictionary converting the gates with standard names to the QASM names for these gates.

See 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

versionstring, 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.

pygsti.tools.internalgates.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

thetafloat

The theta parameter of the u3 gate.

phifloat

The phi parameter of the u3 gate.

lambfloat

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