Overview of examples¶

In addition to the detailed tutorials, InQuanto contains several example scripts showing how various functionality is used. In this file we provide a broad overview of the intention of each example, highlighting the functionality that is demonstrated. Examples using the extensions are found elsewhere.

algorithms/adapt¶

Examples of ADAPT-VQE.

File	Description
`algorithm_adapt.py`	A simulation of H2 in STO-3G using the ADAPT algorithm.
`algorithm_iqeb.py`	A simulation of H2 in STO-3G using IQEB algorithm.
`algorithm_fermionic_adapt.py`	A simulation of H2 in STO-3G using the ADAPT algorithm with fermionic helper functions.

algorithms/qse¶

Examples of Quantum Subspace Expansion.

File	Description
`algorithm_qse.py`	A simulation of H2 in STO-3G using the QSE algorithm

algorithms/time_evolution¶

Examples of time evolution algorithms.

File	Description
`vqs_real_example_paper.py`	A AlgorithmMcLachlanRealTime time evolution simulation for a small system.
`imtime_evolution_example.py`	An exact imaginary time evolution simulation using express methods
`time_evolution_example.py`	An exact time evolution simulation using express methods
`vqs_real_example.py`	A AlgorithmMcLachlanRealTime time evolution simulation
`vqs_imag_example.py`	A AlgorithmMcLachlanImagTime time evolution simulation
`vqs_real_example_paper_phased.py`	A custom equation of motion VQS time evolution simulation.

algorithms/vqd¶

Examples of Variational Quantum Deflation.

File	Description
`algorithm_vqd.py`	Variational Quantum Deflation using computables.

algorithms/vqe¶

Examples of canonical Variational Quantum Eigensolver usage.

File	Description
`algorithm_vqe_ups.py`	A VQE simulation of H4 in STO-3G using UPS Ansatzes.
`algorithm_vqe_hva_hubbard.py`	A VQE simulation of a 2x4 Hubbard model using a HVA Ansatz.
`algorithm_vqe_shots_minimizers.py`	Use of minimizers in shot-based calculations.
`algorithm_vqe_hea.py`	A canonical VQE simulation of H2 in STO-3G using a hardware-efficient Ansatz.
`algorithm_vqe_uccsd.py`	A canonical VQE simulation of H2 in STO-3G using a UCCSD Ansatz.
`algorithm_vqe_hva_chem.py`	A VQE simulation of H2 in STO-3G using a HVA Ansatz.
`algorithm_vqe_unitary_cluster_jastrow.py`	Example running VQE for unitary cluster Jastrow ansatz.
`algorithm_vqe_varCI_sparse.py`	A canonical VQE simulation of H2 in STO-3G using a variational configuration interaction Ansatz.
`algorithm_vqe_varCI.py`	A canonical VQE simulation of H2 in STO-3G using a variational configuration interaction Ansatz.

ansatzes¶

Examples demonstrating usage of Ansatz classes.

File	Description
`multiconfigstate_6qubit.py`	Preparation of a 6 qubit linear combination of fermionic occupation states with fixed coefficients.
`multiconfigstate_4qubit.py`	Preparation of a 4 qubit linear combination of fermionic occupation states with fixed coefficients.
`multiconfigstatesparse_6qubit.py`	Preparation of a 6 qubit linear combination of fermionic occupation states with fixed coefficients.
`multiconfig_with_symbols.py`	Use of a linear combination of fermionic occupation states as a variational ansatz.
`hamiltonian_variational_hubbard.py`	Use of HVA Ansatz for the Hubbard model.
`multiconfigstatebox_4qubit.py`	Preparation of a 4 qubit linear combination of fermionic occupation states with fixed coefficients.
`multireference_builder.py`	Use of reference_circuit_builder to prepare a circuit for a multireference state.
`multiconfigstatesparse_4qubit.py`	Preparation of a 4 qubit linear combination of fermionic occupation states with fixed coefficients.
`multiconfigstatebox_6qubit.py`	Preparation of a 6 qubit linear combination of fermionic occupation states with fixed coefficients.
`unitary_cluster_jastrow.py`	Example demonstrating the use of unitary cluster Jastrow ansatz, both exact and fermionic implementations.
`multiconfigsparse_with_symbols.py`	Use of a linear combination of fermionic occupation states as a variational ansatz.
`fermion_space_ansatze.py`	Use of a general Fermionic Ansatz.
`layered_hea.py`	Use of a layered hardware efficient Ansatz.

computables¶

Examples demonstrating usage of computables classes.

File	Description
`bootstrapping_vs_uvalue.py`	Comparing error bars obtained from bootstrapping (using BackendResultsBootstrap) and linear error propagation.
`bootstrapping_computable.py`	Computable level usage of BackendResult resampling classes for bootstrapping of H2 energy (STO-3G).
`computable_protocol_tutorial.py`	Demonstrates the general use of computables and protocols.
`bootstrapping_simple.py`	Computable level usage of BackendResult resampling classes for bootstrappi

computables/atomic¶

Examples demonstrating usage of atomic computable classes.

File	Description
`expval_noisy_backend.py`	Computable expression example (ExpectationValue)
`using_protocol_list.py`	An example using protocol list for finite differences
`computable_h2_symbolic_derivatives.py`	Use of computables classes for STO-3G H2 expectation value and gradients with symbolic protocol.
`computable_overlap_squared.py`	Computable expression example (OverlapSquared)
`expval_symbolic.py`	Use of symbolic protocol for expectation value.
`expval_pauli.py`	Protocol observable averaging to calculate expectation values.
`derivatives_methods.py`	An example showing how to use evaluate gradients
`computable_h2.py`	Use of computables classes for STO-3G H2 expectation value measurement.
`finite_difference.py`	An example showing how to use evaluate gradients and compare against finite differences

computables/composite¶

Examples demonstrating usage of composite computable classes.

File	Description
`qse_matrices.py`	An example running QSE using computables
`overlap_matrix.py`	Simple overlap matrix calculation.
`hubbard_spin_correlation.py`	A basic Hubbard model example using the spin correlation computable.
`qcm4_computable.py`	Estimating energy using QCM4 computable.
`nonorthogonal_matrices.py`	Basic CI calculation with NonOrthogonal computable.

computables/composite/gf¶

Examples demonstrating usage of Green’s function computable classes.

File	Description
`gf_measurenorm_matrix_mbgf_circuits.py`	Generation of the circuits required for the full GF matrix of the Hubbard dimer.
`krylov_2.py`	Use of KrylovSubspaceComputable to get Green’s function element from shot-based protocol from 1st Lanczos vector.
`krylov_4.py`	Example of evaluating LanczosMatrixComputable with sandwiched moments from shot-based protocol.
`gf_measurenorm_element.py`	Noiseless statevector computation of one element of GF of Hubbard dimer by sandwiching Hamiltonian moments.
`krylov_-1.py`	Example of building your own Lanczos routine, then comparing it to KrylovSubspaceComputable.
`gf_measurenorm_element_shots_2.py`	Computation (shots for Lanczos, shots for ground state) one element of GF of Hubbard dimer.
`krylov_0.py`	Example of evaluating LanczosCoefficientsComputable to get elements of tridiagonal matrix.
`krylov_1.py`	Example of evaluating LanczosMatrixComputable to get tridiagonal matrix for given dimension of Krylov space.
`gf_measurenorm_element_shots_1.py`	Computation (shots for Lanczos, statevector for ground state) one element of GF of Hubbard dimer.
`gf_measurenorm_matrix_mbgf_spectral_shots.py`	Computation of the full GF matrix of the Hubbard dimer with shots, and plot the spectral function A(omega).
`krylov_3.py`	Example of evaluating KrylovSubspaceComputable with sandwiched moments from shot-based protocol.
`gf_measurenorm_matrix_mbgf.py`	Computation (noiseless statevector) the full GF matrix of the Hubbard dimer at a single frequency.
`gf_measurenorm_matrix_mbgf_spectral.py`	Computation of the full GF matrix of the Hubbard dimer, and plot the spectral function A(omega).

computables/composite/rdm¶

Examples demonstrating usage of reduced density matrix computable classes.

File	Description
`rdm_nevpt2.py`	Test of NEVPT2 using RDMs from
`rdm_computable.py`	An example for constructing an RDM using computables

computables/primitive¶

Examples demonstrating usage of primitive computable classes.

File	Description
`basic_primitives.py`	An example showing how to use quantum computables.

core¶

Examples demonstrating usage of logging and debugging functionality.

File	Description
`context_printing.py`	Using context for logging standard outputs

embeddings¶

Examples of usage of embedding methods.

File	Description
`dmet_one_h2x3_express_hf.py`	One-shot DMET calculations on hydrogen rings.
`dmet_one_h2x3_express_vqe.py`	One-shot DMET calculations on hydrogen rings
`impurity_dmet_h2x3_express_vqe.py`	An example impurity DMET simulation of a 3-dihydrogen ring using the express module.
`dmet_full_h2x3_express_hf.py`	Full DMET calculations on hydrogen rings.

express¶

Examples of usage of the built-in example molecular data in InQuanto.

File	Description
`hubbard_driver_example.py`	1D and 2D Hubbard driver example
`h5_operations.py`	Built-in example molecular data.
`get_started_express.py`	Basic code snippets to use express, operators and states.

hugr¶

File	Description
`projective_measurements_hugr.py`	Example using a simple ProjectiveMeasurements protocol.

mappings¶

Examples of fermion-qubit mapping functionality.

File	Description
`mapping_jw.py`	Use of the Jordan-Wigner mapping from fermions to qubits.
`mapping_bk.py`	Use of the Bravyi-Kitaev mapping from fermions to qubits.
`mapping_paraparticular.py`	Use and comparison of the paraparticle mapping from fermions to qubits

minimizers¶

Examples of classical minimizers in InQuanto.

File	Description
`integrators.py`	Symbolic evaluation and comparing integrator methods.
`minimizers.py`	Use of minimizers.

operators¶

Examples of functionality of operator and state classes.

File	Description
`qubit_state.py`	Construction of QubitState and demonstration of some functionality.
`double_factorization_h2.py`	Simple shot-based energy calculation using a double factorized hamiltonian.
`fermion_state.py`	Creation of FermionState objects and demonstration of some functionality.
`orbital_optimizer.py`	Orbital optimization using Pipek-Mezey as an example.
`qubit_operator.py`	Construction of QubitOperator and demonstration of some functionality.
`chemistry_integral_operators.py`	Creation of ChemistryRestrictedIntegralOperator (CRIO) and conversion to FermionOperator.
`double_factorization_lih_sv.py`	Statevector calculations of energy with a double factorized hamiltonian.
`orbital_transformer.py`	Orbital transformation methods.
`double_factorization_h3.py`	Simple shot-based energy calculation using a double factorized, unrestricted-spin hamiltonian.
`fermion_operator.py`	Examples of some FermionOperator methods.

protocols¶

Examples demonstrating usage of protocol classes.

File	Description
`feature_projective_measurements.py`	Example using a simple ProjectiveMeasurements protocol.
`expval_pmsv.py`	Example using PMSV error mitigation to calculate expectation values.
`expval_mitigation_methods+qermit.py`	Running protocols via Qermit’s MitRes and MitEx and inquanto’s noise mitigation.
`bootstrapping_expval.py`	Low level usage of BackendResult resampling classes, like Bootstrapping.
`pauli_hadamard_protocols.py`	Usage of the PauliAveraging and HadamardTest protocols.
`hadamard_df_grad_expr.py`	Use of Hadamard test derivative for STO-3G H2 expectation value measurement.
`hadamard_df_grad_hea.py`	Use of Hadamard test derivative for STO-3G H2 expectation value measurement with a hardware-efficient ansatz.
`expval_spam.py`	Running PauliAveraging with inquanto’s noise mitigation.
`expval_spam_mitres_h2.py`	Running SPAM error mitigation via Qermit MitRes on measurement of expectation value for H2.
`overlap_squared_protocols.py`	Compare different shot based protocols for calculating an overlap squared.
`factorized_overlap.py`	Calculating complex overlaps with the FactorizedOverlap protocols and comparing to HadamardTestOverlap.
`feature_credits_cost.py`	Protocol observable averaging to calculate expectation values.
`hadamard_direct_df_grad_expr.py`	Use of Hadamard test derivative for STO-3G H2 expectation value measurement in direct and indirect mode.
`feature_partition_strategy.py`	Partition measurement reduction strategies for PauliAveraging protocol.
`feature_observable_averaging.py`	Protocol observable averaging to calculate expectation values.
`qermit_spam_zne.py`	Running protocols via Qermit’s MitRes and MitEx.
`hadamard_test_overlap.py`	Calculating complex overlaps with the HadamardTestOverlap protocol.

protocols/phase_estimation¶

Examples demonstrating usage of the quantum phase estimation protocols.

File	Description
`sin-state_qpe_2x2_matrix.py`	Demonstration of the generation and use of sin-state phase estimation circuits, and plotting of results.
`hadamard_test_iqpe.py`	Demonstration of the generation of IPEA circuits, and their use for Hadamard test sampling.
`hadamard_test_iqpe_statevector.py`	Demonstration of the generation of IPEA unitaries for statevector simulation.
`hadamard_test_iqpe_quantinuum.py`	Demonstration of the generation of IPEA circuits with the specialized Quantinuum protocols.

spaces¶

Examples of space classes for generating operators and states.

File	Description
`fermion_spaces.py`	Use of FermionSpace objects to generate fermionic states and operators, including point group symmetry.
`parafermion_space.py`	Use of ParaFermionSpace objects to generate parafermionic states and operators.
`qubit_spaces.py`	Use of QubitSpace object to generate qubit operators.

symmetry¶

Examples of symmetry classes and functionality.

File	Description
`fermionic_symmetry_operators.py`	Finding fermionic Z2 symmetry operators.
`qubit_symmetry_operators.py`	Finding qubit Z2 symmetry operators.
`qubit_tapering.py`	Qubit tapering - operators and Ansatzae.
`point_group.py`	Use of PointGroup class containing point group symmetry information.