CircuitOperationList

CircuitOperationList#

class iqm.pulse.circuit_operations.CircuitOperationList(contents=(), *, qubits=None, num_qubits=0, table=None)#

Bases: list

List of CircuitOperation objects representing a quantum circuit.

The class is used to work with CircuitOperations directly. It is mostly meant as convenience to enable easy creation of circuits, calculations of their properties, and mapping them onto physical qubits. In addition to the circuit contents, this class has two important attributes: qubits and table.

qubits defines the list of qubits which are allowed to be in the loci of all the CircuitOperations present in the list. Think about it as Qiskit’s QuantumRegister.

table is a QuantumOpTable, which contains all the QuantumOp s which are allowed in the circuit. In most cases, the table is simply taken to contain all the default operations defined in iqm.pulse. When you use this class with a ScheduleBuilder, it is good practice to set table = builder.op_table. The QuantumOpTable is mutable, so any additional registered gates can automatically be usable in any CircuitOperationList associated with that ScheduleBuilder instance.

The fundamental use of the class would be to first define a new instance:

circuit = CircuitOperationList(num_qubits=2)

The num_qubits parameter populates the qubits attribute with qubits QB1-QBn, in this case ['QB1', 'QB2'].

Alternatively, you can provide qubits directly:

circuit = CircuitOperationList(qubits=['QB1', 'QB2'])

To add your own QuantumOpTable, initialize like this:

circuit = CircuitOperationList(num_qubits=2, table=my_table)

Remembering that the table is mutable.

If you already have a list of CircuitOperations, you can initialize with it:

circuit = CircuitOperationList(circuit_ops, table=my_table)
circuit.find_qubits()

Calling the find_qubits() method populates the qubits attribute with the qubits found in loci of the operations in the original circuit. If the list is empty, it will set qubits to an empty list, which most of the time is not what you want to do.

The class has the __add__, __mul__ and __getitem__ methods redefined, which means circuit * 3, circuit1 + circuit2 and circuit[0:4] will produce a CircuitOperationList with the same qubits and table attributes as the original.

To add a prx operation to the list, call:

circuit.add_op('prx', [0], angle, phase, impl_name='drag_crf')

The class also has shortcut methods defined, so the above can be shortened to

circuit.prx(angle, phase, 0, impl_name='drag_crf')

which is exactly the same syntax as in Qiskit, with the addition of the implementation name which usually does not need to be used. The names of the shortcut methods are taken from the attached table at init. All the operations with non-zero arity will be added as shortcuts.

If all the operations in the circuit are unitary, you can calculate the unitary propagator of the entire circuit by calling:

U = circuit.get_unitary()

The dimension of the unitary will always be defined by the qubits attribute. In particular, if your circuit contains 3 qubits, 'QB1', 'QB2', 'QB3', but you only add gates to the first two, the resulting unitary will still be an 8x8 matrix, corresponding to the three qubits 'QB1', 'QB2', 'QB3', in the big endian convention. With no operations affecting 'QB3', the action of the unitary on this qubit is identity.

To map the circuit onto physical qubits, all you need to do is call:

physical_circuit = circuit.map_loci(physical_qubits)

This will create a copy of the circuit, with all the placeholder qubits replaced by the physical qubits, with the order defined by the qubits attribute. For example, if qubits = ['QB1', 'Alice', 'ZZZ'], and physical_qubits = ['QB2', 'QB5', 'QB10'], all occurrences of 'QB1' will be mapped to 'QB2', 'Alice' to 'QB5' and 'ZZZ' to 'QB10'. The original circuit is not modified, so you can create many copies with different physical qubits, which is helpful when running parallel experiments on a large chip.

Parameters:

  • contents (Iterable[CircuitOperation]) – Circuit operations to initialize the circuit with. Can be left out.

  • qubits (list[str]) – Qubits allowed to be used in operation loci in the circuit.

  • num_qubits (int) – Number of qubits in the circuit, will initialize qubits with ['QB1', 'QB2', ...]. Ignored if qubits is given.

  • table (QuantumOpTable | None) – Allowed quantum operations.

Module: iqm.pulse.circuit_operations

Attributes

qubits

Methods

add_op

Adds a new CircuitOperation to the circuit.

add_qubits

Adds generic placeholder qubits from 1 to n.

barrier

Add barrier to the circuit

compose

A safer way to add circuits together, but will probably take time.

count_ops

Count each type of operation in the circuit.

find_qubits

Set attribute qubits to qubits in the loci of operations in the list.

get_unitary

Calculate the overall unitary implemented by a sequence of CircuitOperations.

map_loci

Creates a new list of CircuitOperation s with locus mapped onto physical qubits.
find_qubits()#

Set attribute qubits to qubits in the loci of operations in the list.

Return type:

None

add_qubits(n)#

Adds generic placeholder qubits from 1 to n.

Parameters:

n (int)

Return type:

None

get_unitary(qubit_names=None)#

Calculate the overall unitary implemented by a sequence of CircuitOperations.

Parameters:

  • self – list of CircuitOperations in order

  • qubit_names (list[str] | None) – Optionally, the ordering of the qubits.

Returns:

Array describing the action of the circuit in big endian convention.

Return type:

ndarray

add_op(name, locus_indices, *args, impl_name=None)#

Adds a new CircuitOperation to the circuit.

Appends a new CircuitOperation at the end of the list. The CircuitOperation is created using a QuantumOp name from the QuantumOpTable attached to the CircuitOperationList. The locus of that CircuitOperation is built from the qubits stored in qubits, by selecting the qubits at indices given by locus_indices. For example, if qubits is ['QB1', 'QB2', 'QB4'], and the locus_indices is [2, 1], the locus of the new CircuitOperation will be ('QB4', 'QB2'). All arguments for the values of the params of the requested QuantumOp need to be provided.

Parameters:

  • name (str) – Name of the QuantumOp which will generate a new CircuitOperation.

  • locus_indices (Sequence[int]) – Indices of the qubits in the attribute .qubits which will become the locus of the operation.

  • args – Any arguments the CircuitOperation needs, must correspond to the params of the QuantumOp.

  • impl_name (str | None) – Name of the implementation to use when converting the CircuitOperation into a Timebox later.

Return type:

None

barrier(*locus_indices)#

Add barrier to the circuit

Return type:

None

compose(other, locus_indices=None)#

A safer way to add circuits together, but will probably take time.

All the CircuitOperation s from the 'other' list are appended to the end of this list. The wire k of the second circuit is connected to wire locus_indices[k] of the first. This is achieved by mapping the locus of each operation in the second circuit onto the qubits of the first.

For example, if the qubits of the first list are ['QB1', 'QB2'], the second list has ['QB3', 'QB4'], and the locus_indices argument is [1,0], all the operations in the second list will have their 'QB3' mapped to 'QB2' and 'QB4' mapped to 'QB1'.

Parameters:

  • other – Second CircuitOperationList. Must have less or equal qubits than this one.

  • locus_indices (list[int] | None) – Indices of the qubits in this CircuitOperationList onto which the qubits in the second circuit ar mapped.

Returns:

Self, with new operations added.

Return type:

Self

count_ops()#

Count each type of operation in the circuit.

Returns:

Counter mapping operation names to numbers of times they occur in the circuit.

Return type:

Counter

map_loci(locus, make_circuit=True)#

Creates a new list of CircuitOperation s with locus mapped onto physical qubits.

Creates a fresh list of fresh CircuitOperation s with fresh arguments. If locus is provided, it needs to have the same length as the total number of qubits across the circuit, and the qubits will then be mapped onto the new locus. If it is not provided, this is identical to a deepcopy of the original list.

Parameters:

  • locus (list[str] | None) – List of new qubits to replace the qubits in the loci of the operations in the circuit.

  • make_circuit (bool) – If True, creates a CircuitOperationList. If False, it is just a list.

Returns:

New CircuitOperationList with loci mapped onto new locus.

Return type:

CircuitOperationList | list[CircuitOperation]

_set_specific_operation_shortcut(name)#

Add the convenience methods for adding new operations, based on the default QuantumOpTable.

Parameters:

name (str)

Return type:

None

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