import {LoopEngine} from 'projectq/src/meta/loop.js'

public class | source

LoopEngine

Extends:

BasicEngine → LoopEngine

Stores all commands and, when done, executes them num times if no loop tag handler engine is available. If there is one, it adds a loop_tag to the commands and sends them on.

Constructor Summary

Public Constructor
public	constructor(num: number)

Member Summary

Private Members
private	_allocatedQubitIDs: *
private	_cmdList: *[]
private	_deallocatedQubitIDs: *
private	_nextEnginesSupportLoopTag: boolean
private	_refsToLocalQB: {}
private	_tag: *

Method Summary

Public Methods
public	receive(commandList: Command[]) Receive (and potentially temporarily store) all commands.
public	run() Apply the loop statements to all stored commands.

Inherited Summary

From class BasicEngine
public	isLastEngine: boolean
public	allocateQubit(dirty: boolean): Qureg Return a new qubit as a list containing 1 qubit object (quantum register of size 1).
public	allocateQureg(n: number): Qureg Allocate n qubits and return them as a quantum register, which is a list of qubit objects.
public	deallocateQubit(qubit: BasicQubit) Deallocate a qubit (and sends the deallocation command down the pipeline).
public	isAvailable(cmd: Command): boolean Default implementation of isAvailable: Ask the next engine whether a command is available, i.e., whether it can be executed by the next engine(s).
public	isMetaTagSupported(metaTag: function): boolean Check if there is a compiler engine handling the meta tag
public	receive()
public	send(commandList: Command[]) Forward the list of commands to the next engine in the pipeline.

Public Constructors

public constructor(num: number) source

Override:

BasicEngine#constructor

Params:

Name	Type	Attribute	Description
num	number		Number of loop iterations.

Private Members

private _allocatedQubitIDs: * source

private _cmdList: *[] source

private _deallocatedQubitIDs: * source

private _nextEnginesSupportLoopTag: boolean source

private _refsToLocalQB: {} source

private _tag: * source

Public Methods

public receive(commandList: Command[]) source

Receive (and potentially temporarily store) all commands.

Add LoopTag to all receiving commands and send to the next engine if a further engine is a LoopTag-handling engine. Otherwise store all commands (to later unroll them). Check that within the loop body, all allocated qubits have also been deallocated. If loop needs to be unrolled and ancilla qubits have been allocated within the loop body, then store a reference all these qubit ids (to change them when unrolling the loop)

Override:

BasicEngine#receive

Params:

Name	Type	Attribute	Description
commandList	Command[]		List of commands to store and later unroll or, if there is a LoopTag-handling engine, add the LoopTag.

public run() source

Apply the loop statements to all stored commands. Unrolls the loop if LoopTag is not supported by any of the following engines, i.e., if

Example:

is_meta_tag_supported(next_engine, LoopTag) == false