Wraps an existing Gate for density matrix operations. More...

#include <gate_operation.h>

Inheritance diagram for squander::density::GateOperation:

Public Member Functions
void	apply_to_density (const double *params, int param_count, DensityMatrix &rho) override
	Apply gate to density matrix using optimized local kernel. More...

std::unique_ptr< IDensityOperation >	clone () const override
	Create a deep copy of this operation. More...

	GateOperation (Gate *gate, bool owns_gate=true)
	Wrap an existing gate. More...

	GateOperation (const GateOperation &)=delete

	GateOperation (GateOperation &&other) noexcept

int	get_control_qbit () const
	Get control qubit index (-1 if not a controlled gate) More...

Gate *	get_gate () const
	Get the underlying gate (for inspection) More...

std::string	get_name () const override
	Get operation name for debugging/display. More...

int	get_parameter_num () const override
	Get number of free parameters this operation requires. More...

int	get_target_qbit () const
	Get target qubit index. More...

bool	is_unitary () const override
	Check if this is a unitary operation (gate) or non-unitary (noise) More...

GateOperation &	operator= (const GateOperation &)=delete

GateOperation &	operator= (GateOperation &&other) noexcept

	~GateOperation () override
	Destructor - deletes gate if owns_gate was true. More...

Private Attributes
Gate *	gate_

bool	owns_gate_

Detailed Description

Wraps an existing Gate for density matrix operations.

This adapter allows existing SQUANDER gates (H, CNOT, RZ, etc.) to be used in noisy circuits operating on density matrices.

Uses optimized local kernel application:

Single-qubit gates: O(2^{2N}) instead of O(2^{3N})
Two-qubit gates: O(2^{2N+2}) instead of O(2^{3N})

Does NOT modify the original Gate class - clean separation of concerns.

Example:

Gate* h = new H(2, 0);
auto op = std::unique_ptr<GateOperation>(new GateOperation(h, true));
op->apply_to_density(nullptr, 0, rho);  // H on qubit 0

Definition at line 45 of file gate_operation.h.

Constructor & Destructor Documentation

◆ GateOperation() [1/3]

squander::density::GateOperation::GateOperation	(	Gate *	gate,
		bool	owns_gate = `true`
	)

Wrap an existing gate.

Parameters

gate	The gate to wrap
owns_gate	If true, this wrapper will delete the gate on destruction

Definition at line 32 of file gate_operation.cpp.

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◆ ~GateOperation()

squander::density::GateOperation::~GateOperation ( )

override

Destructor - deletes gate if owns_gate was true.

Definition at line 39 of file gate_operation.cpp.

◆ GateOperation() [2/3]

squander::density::GateOperation::GateOperation ( const GateOperation & )

delete

◆ GateOperation() [3/3]

squander::density::GateOperation::GateOperation ( GateOperation && other )

noexcept

Definition at line 50 of file gate_operation.cpp.

Member Function Documentation

◆ apply_to_density()

void squander::density::GateOperation::apply_to_density	(	const double *	params,
		int	param_count,
		DensityMatrix &	rho
	)

overridevirtual

Apply gate to density matrix using optimized local kernel.

For single-qubit gates, applies the 2x2 kernel directly. For two-qubit gates, applies the 4x4 kernel directly. This is O(2^{2N+k}) instead of O(2^{3N}) for k-qubit gates.

Implements squander::density::IDensityOperation.

Definition at line 73 of file gate_operation.cpp.

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