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_fermionic_adapt.py	A simulation of H2 in STO-3G using the ADAPT algorithm with fermionic helper functions.
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.

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

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_shots_minimizers.py	Use of minimizers in shot-based calculations.
algorithm_vqe_uccsd.py	A canonical VQE simulation of H2 in STO-3G using a UCCSD Ansatz.
algorithm_vqe_hea.py	A canonical VQE simulation of H2 in STO-3G using a hardware-efficient 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
multiconfigstatebox_6qubit.py	Preparation of a 6 qubit linear combination of fermionic occupation states with fixed coefficients.
multiconfigstate_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.
layered_hea.py	Use of a layered hardware efficient Ansatz.
multiconfigstate_4qubit.py	Preparation of a 4 qubit linear combination of fermionic occupation states with fixed coefficients.
multiconfigstatebox_4qubit.py	Preparation of a 4 qubit linear combination of fermionic occupation states with fixed coefficients.
fermion_space_ansatze.py	Use of a general Fermionic Ansatz.

computables

Examples demonstrating usage of computables classes.

File	Description
computable_protocol_tutorial.py	Demonstrates the general use of computables and protocols.

computables/atomic

Examples demonstrating usage of atomic computable classes.

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

computables/composite

Examples demonstrating usage of composite computable classes.

File	Description
nonorthogonal_matrices.py	Basic CI calculation with NonOrthogonal computable.
overlap_matrix.py	Simple overlap matrix calculation.
qse_matrices.py	An example running QSE using computables
qcm4_computable.py	Estimating energy using QCM4 computable.

computables/composite/gf

Examples demonstrating usage of Green’s function computable classes.

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

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
symbols.py	Simple demonstrations of manipulating Symbols and SymbolDict in inquanto

embeddings

Examples of usage of embedding methods.

File	Description
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.
dmet_one_h2x3_express_vqe.py	One-shot DMET calculations on hydrogen rings
dmet_one_h2x3_express_hf.py	One-shot DMET calculations on hydrogen rings.

express

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

File	Description
get_started_express.py	Basic code snippets to use express, operators and states.
h5_operations.py	Built-in example molecular data.

mappings

Examples of fermion-qubit mapping functionality.

File	Description
mapping_bk.py	Use of the Bravyi-Kitaev mapping from fermions to qubits.
mapping_jw.py	Use of the Jordan-Wigner 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
fermion_operator.py	Examples of some FermionOperator methods.
qubit_state.py	Construction of QubitState and demonstration of some functionality.
orbital_optimizer.py	Orbital optimization using Pipek-Mezey as an example.
fermion_state.py	Creation of FermionState objects and demonstration of some functionality.
orbital_transformer.py	Orbital transformation methods.
double_factorization_h2.py	Simple energy calculation using a double factorized hamiltonian.
chemistry_integral_operators.py	Creation of ChemistryRestrictedIntegralOperator (CRIO) and conversion to FermionOperator.
qubit_operator.py	Construction of QubitOperator and demonstration of some functionality.

protocols

Examples demonstrating usage of protocol classes.

File	Description
expval_mitigation_methods+qermit.py	Running protocols via Qermit’s MitRes and MitEx and inquanto’s noise mitigation.
phase_shift_df_grad_expr.py	Use of phase shift derivative for STO-3G H2 expectation value measurement.
expval_pmsv.py	Example using PMSV error mitigation to calculate expectation values.
expval_spam.py	Running PauliAveraging with inquanto’s noise mitigation.
hadamard_direct_df_grad_expr.py	Use of phase shift derivative for STO-3G H2 expectation value measurement.
factorized_overlap.py	Calculating complex overlaps with the FactorizedOverlap protocols and comparing to HadamardTestOverlap.
pauli_hadamard_protocols.py	Usage of the PauliAveraging and HadamardTest protocols.
overlap_squared_protocols.py	Compare different shot based protocols for calculating an overlap squared.
feature_partition_strategy.py	Partition measurement reduction strategies for PauliAveraging protocol.
hadamard_test_overlap.py	Calculating complex overlaps with the HadamardTestOverlap protocol.
phase_shift_df_grad_hea.py	Use of phase shift derivative for STO-3G H2 expectation value measurement.
feature_credits_cost.py	Protocol observable averaging to calculate expectation values.
feature_observable_averaging.py	Protocol observable averaging to calculate expectation values.
qermit_spam_zne.py	Running protocols via Qermit’s MitRes and MitEx.
feature_projective_measurements.py	Example using a simple ProjectiveMeasurements protocol.

protocols/phase_estimation

Examples demonstrating usage of the quantum phase estimation protocols.

File	Description
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.
hadamard_test_iqpe.py	Demonstration of the generation of IPEA circuits, and their use for Hadamard test sampling.

spaces

Examples of space classes for generating operators and states.

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

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.
point_group.py	Use of PointGroup class containing point group symmetry information.
qubit_tapering.py	Qubit tapering - operators and Ansatzae.