DensityMatrixSimulator{T, S<:AbstractMatrix{T}} <: AbstractSimulator

Simulator representing evolution of a density matrix of type S, with element type T. Density matrix simulators should be used to simulate circuits with noise.

DensityMatrixSimulator([::T], qubit_count::Int, shots::Int) -> DensityMatrixSimulator{T, Matrix{T}}

Create a DensityMatrixSimulator with 2^qubit_count x 2^qubit_count elements and shots shots to be measured. The default element type is ComplexF64.

StateVectorSimulator{T, S<:AbstractVector{T}} <: AbstractSimulator

Simulator representing a pure state evolution of a statevector of type S, with element type T. State vector simulators should be used to simulate circuits without noise.

StateVectorSimulator([::T], qubit_count::Int, shots::Int) -> StateVectorSimulator{T, Vector{T}}

Create a StateVectorSimulator with 2^qubit_count elements and shots shots to be measured. The default element type is ComplexF64.

properties(svs::DensityMatrixSimulator) -> GateModelSimulatorDeviceCapabilities

Query the properties and capabilities of a DensityMatrixSimulator, including which gates and result types are supported and the minimum and maximum shot and qubit counts.

properties(svs::StateVectorSimulator) -> GateModelSimulatorDeviceCapabilities

Query the properties and capabilities of a StateVectorSimulator, including which gates and result types are supported and the minimum and maximum shot and qubit counts.

simulate(simulator::AbstractSimulator, circuit_ir; shots::Int = 0, kwargs...) -> GateModelTaskResult

Simulate the evolution of a statevector or density matrix using the passed in simulator. The instructions to apply (gates and noise channels) and measurements to make are encoded in circuit_ir. Supported IR formats are OpenQASMProgram (OpenQASM3) and Program (JAQCD). Returns a GateModelTaskResult containing the individual shot measurements (if shots > 0), final calculated results, circuit IR, and metadata about the task.

evolve!(dms::DensityMatrixSimulator{T, S<:AbstractMatrix{T}}, operations::Vector{Instruction}) -> DensityMatrixSimulator{T, S}

Apply each operation of operations in-place to the density matrix contained in dms.

Effectively, perform the operation:

$\hat{\rho} \to \hat{A}^\dag \hat{\rho} \hat{A}$

for each operation $\hat{A}$ in operations.

evolve!(svs::StateVectorSimulator{T, S<:AbstractVector{T}}, operations::Vector{Instruction}) -> StateVectorSimulator{T, S}

Apply each operation of operations in-place to the state vector contained in svs.

Effectively, perform the operation:

$\left| \psi \right\rangle \to \hat{A} \left| \psi \right\rangle$

for each operation $\hat{A}$ in operations.

expectation(dms::DensityMatrixSimulator, observable::Observables.Observable, targets::Int...) -> Float64

Compute the exact (shots=0) expectation value of observable applied to targets given the evolved density matrix in dms. In other words, compute

$\mathrm{Tr}\left(\hat{O}\hat{\rho}\right)$.

expectation(svs::StateVectorSimulator, observable::Observables.Observable, targets::Int...) -> Float64

Compute the exact (shots=0) expectation value of observable applied to targets given the evolved state vector in svs. In other words, compute

$\langle \psi | \hat{O} | \psi \rangle$.

probabilities(svs::StateVectorSimulator) -> Vector{Float64}

Compute the observation probabilities of all amplitudes in the state vector in svs.