CHANGELOG.md

Planned changes for v1.0.0:

• permute will be a wrapper around to QuantumInterface.permutesubsystems. Documentation for permute! would be similarly updated
• reworking the rest of NoisyCircuits and moving it out of Experimental

News

v0.9.16 - dev

• Enhancements to GF(2) Linear Algebra: unexported, experimental gf2_row_echelon_with_pivots!, gf2_nullspace, gf2_rowspace_basis.

v0.9.15 - 2024-12-22

• pftrajectories now supports fast multiqubit measurements with PauliMeasurement in addition to the already supported single qubit measurements sMX/Z/Y and workarounds like naive_syndrome_circuit.

v0.9.14 - 2024-11-03

• (fix) affectedqubits() on sMX, sMY, and sMR*
• (fix) restrictive type-assert in MixedDestabilizer failing on views of tableaux
• Implementing additional named two-qubit gates: sSQRTXX, sInvSQRTXX, sSQRTYY, sInvSQRTYY

v0.9.13 - 2024-10-30

• New error-correction group theory tools:
  • canonicalize_noncomm function to find a generating set with minimal anticommutivity
  • SubsystemCodeTableau data structure to represent the output of canonicalize_noncomm
  • commutify function to find a commutative version of a non-commutative set of Paulis with minimal changes
  • matroid_parent to, for set of Paulis that doesn't represent a state, find a version that does.
• Implementing additional named two-qubit gates: sSWAPCX, sInvSWAPCX, sCZSWAP, sCXSWAP, sISWAP, sInvISWAP, sSQRTZZ, sInvSQRTZZ

v0.9.12 - 2024-10-18

• Minor compat fixes for julia 1.11 in the handling of hgp

v0.9.11 - 2024-09-27

• hcat of Tableaux objects
• QuantumReedMuller codes added to the ECC module
• (breaking) change the convention for how to provide a representation function in the constructor of LPCode -- strictly speaking a breaking change, but this is not an API that is publicly used in practice

v0.9.10 - 2024-09-26

• The lifted product class of quantum LDPC codes is implemented in the ECC submodule.
• (fix) ECC.code_s now gives the number of parity checks with redundancy. If you want the number of linearly independent parity checks, you can use LinearAlgebra.rank.
• Implementing many more named single-qubit gates following naming convention similar to the stim package in python.
• (fix) Bug fix to the parity_checks(ReedMuller(r, m)) of classical Reed-Muller code (it was returning generator matrix).
• RecursiveReedMuller code implementation as an alternative implementation of ReedMuller.

v0.9.9 - 2024-08-05

• inv is implemented for all Clifford operator types (symbolic, dense, sparse).

v0.9.8 - 2024-08-03

• New group-theoretical tools:
  • groupify to generate full stabilizer group from generating set
  • minimal_generating_set function to find the minimal generating set of a set of operators
  • pauligroup to generate the full Pauli group of a certain number of qubits
  • normalizer to generate all Paulis that commute with a set of Paulis
  • centralizer to find a subset of a set of Paulis such that each element in the subset commutes with each element in the set
  • contractor to find a subset of Paulis in a tableau that have an identity operator on a certain qubit
  • delete_columns to remove the operators corresponding to a certain qubit from all Paulis in a Stabilizer
• PauliError can now encode biased noise during Pauli frame simulation, i.e. one can simulate only X errors, or only Y errors, or only Z errors, or some weighted combination of these.

v0.9.7 - 2024-07-23

• (fix #320) Fix a serious correctness bug in the SIMD implementation of Pauli string multiplication (affects the correctness of canonicalization and traceout for tableaux bigger than ~500 qubits; does not affect symbolic gates or Pauli frame simulations of any scale)

v0.9.6 - 2024-07-12

• inv implementation for single-qubit "symbolic" Clifford operators (subtypes of AbstractSingleQubitOperator).

v0.9.5 - 2024-07-04

• Implementation of random all-to-all and brickwork Clifford circuits and corresponding ECC codes.

v0.9.4 - 2024-06-28

• Addition of a constructor for concatenated quantum codes Concat.
• Addition of multiple unexported classical code constructors.
• Gate errors are now conveniently supported by the various ECC benchmark setups in the ECC module.
• Significant improvements to the low-level circuit compiler (the sumtype compactifier), leading to faster Pauli frame simulation of noisy circuits.
• Bump QuantumOpticsBase.jl package extension compat bound.
• (fix) Remove printing of spurious debug info from the PyBP decoder.
• (fix) Failed compactification of gates now only raises a warning instead of throwing an error. Defaults to slower non-compactified gates.

v0.9.3 - 2024-04-10

• (fix) One of random_pauli's methods was disregarding the error probability and had incorrect kwarg defaults.

v0.9.2 - 2024-04-08

• The ECC module now has access to an iterative bitflip decoder thanks to LDPCDecoders.jl.
• Provide more configuration options in the PyBeliefProp decoders.
• (fix) The belief prop decoder from LDPCDecoders was counting iterations incorrectly.

v0.9.1 - 2024-03-31

• Implemented iscss function to identify whether a given code is known to be a CSS (Calderbank-Shor-Steane) code.
• Added the classical Reed-Muller code in the ECC module.
• Added the surface code to the ECC module.

v0.9.0 - 2024-03-19

• (breaking) The defaults in random_pauli are now realphase=true and nophase=true.
• (breaking) The convention for for flip probability in random_pauli.
• (breaking) The convention for noise probability in UnbiasedUncorrelatedNoise changed. The input number is the total probability for an error to occur.
• Implement an inplace random_pauli!, a non-allocating alternative to random_pauli.
• Significant improvement in the performance of the ECC decoder pipeline (but many low-hanging fruits still remain).

v0.8.21 - 2024-03-17

• Implemented the Gottesman code family, also known as [[2^j, 2^j - j - 2, 3]] quantum Hamming codes.
• Bump the PyQDecoders dependency, switching to PythonCall behind the scenes for reliability.
• Bump the LDPCDecoders dependency.

v0.8.20 - 2024-01-22

• Significant additions to the ECC submodule, with constructors for a few new codes (Toric and generic CSS); incorporating many syndrome decoding algorithms (thanks to the PyQDecoders.jl and LDPCDecoders.jl packages); and providing a convenient API for evaluating code performance in different settings through the new evaluate_decoder function.

v0.8.19 - 2023-12-16

• Bumping up the lower bounds of many dependencies and adding lower-bound compatibility checks to CI.

v0.8.18 - 2023-11-22

• ECC.faults_matrix detects and warns when encountery codes with redundant checks.

v0.8.17 - 2023-10-17

• (fix) Some affectedqubits methods were returning single integers instead of a one-tuple.
• The non-public ECC module has seen a few improvements (a naive_encoding_circuit implementation and a few new codes), as well as some breaking changes to API.

v0.8.16 - 2023-08-31

• (breaking) Changes to the circuit generation in the non-public ECC module. Adding a Shor syndrome measurement circuit.
• Added a ClassicalXOR gate, for now supporting only PauliFrames.

v0.8.15 - 2023-08-16

• Initial support for GPU accelerated circuit simulation (with CUDA).
• Minor documentation fixes around phases and a workaround for Makie plotting regression.

v0.8.14 - 2023-07-19

• Circuit plotting with Quantikz from inside other modules (common with Pluto) showed wrong names for gates due to how we were serializing the names. It is now fixed.

v0.8.13 - 2023-07-18

• (fix) There was a bug with incorrect scaling for Operator(::CliffordOperator) conversions.
• A few more features to the ECC module's circuit generation routines.
• Quantikz circuit plotting improvements to CliffordOperator and s*CY and sYC*.

v0.8.12 - 2023-07-12

• Initial implementation of non-Clifford simulation (mainly for circuits that are slightly non-Clifford, e.g. containing T gates). See StabMixture, PauliChannel, UnitaryPauliChannel, and pcT.
• embed implemented for PauliOperator and PauliChannel.
• Various convenience constructors that transform a tableaux or an operator into a Ket or Operator from QuantumOptics.jl. Use the constructors directly like Ket(::Stabilizer), Operator(::CliffordOperator), etc.

v0.8.11 - 2023-07-10

• petrajectories, for (potentially symbolic) perturbative expansions of the result of a circuit, is moved out of Experimental into the public part of the interface. The underlying petrajectory is not made public yet due to the ad-hoc low-level return conventions for it.
• mctrajectory and petrajectory can now optionally report the end state of each trajectory, not just the circuit status (i.e. "success", "detected failure", etc).
• Internally we now use a trait system to distinguish deterministic from non-deterministic operations. Not part of the public API yet.

v0.8.10 - 2023-07-05

• Remove Polyester.jl multithreading, leading to simpler and better compiled single-thread code. Now single-thread performance is much higher. Multithreading was generally not useful at the inner loops where it was deployed.
• Implement fastcolumn and fastrow, which transform a tableau into a memory layout optimized for column or row operations.

v0.8.9 - 2023-07-04

• In the unexported experimental ECC module:
  • we now implement fault_matrix which gives the mapping between single-qubit physical errors and logical observables.
  • MixedDestabilizer and Stabilizer now have constructors when acting on an ECC object.
• stab_to_gf2 now works with Pauli operators as well.

v0.8.8 - 2023-06-23

• Bump QuantumInterface compat.

v0.8.7 - 2023-06-22

• Better UX and threading support for pftrajectories.
• affectedqubits now more consistently returns tuples instead of vectors.
• Private affectedbits is now implemented.
• Many operation constructors now throw an error if they are given negative qubit indices.

v0.8.6 - 2023-06-20

• Fixes to Quantikz circuit plotting of empty circuits and PauliOperator

v0.8.5 - 2023-06-13

• Internal helper method mul_right! is now available for right Pauli inplace multiplication.
• Implemented sMRZ to reset single qubits to the |0⟩ (and respectively sMRX and sMRY).

v0.8.4 - 2023-06-11

• Bump QuantumInterface to 0.2.0.

v0.8.3 - 2023-06-10

• Improvements to printing and documentation.

v0.8.2 - 2023-05-22

• Initial, experimental, unexported helper functions for work with error correcting codes. Might change at any time.

v0.8.1 - 2023-05-17

• (fix) Fix to Quantikz circuit plotting functions.

v0.8.0 - 2023-05-16

• (breaking) Deprecated the QuantumCliffordPlots library and moved that functionality to 3 package extensions, one for each of Quantikz, Plots, and Makie visualizations.
• (breaking) Set minimum requirements to Julia 1.9
• Initial implementation of Pauli frame simulations (with pftrajectories and PauliFrame)
• Initial support for "sum type" gates for much faster dispatch (with compactify_circuit)
• (fix) Fixes to print/show formatting.

v0.7.2 - 2023-04-09

• Non-standard string literals P, T, S, and C (e.g. P"X" used to create a Pauli operator) are now not cached at compile time. Before this version f() = P"X" would have resulted in f() === f(), while now that statement would return false. Change made given that the objects created by these literals are mutable which can lead to bugs where a local variable seems to "remember" how it is being modified at each execution of a function.

v0.7.1 - 2023-04-08

• Better printing of tableaux and operators.

v0.7.0 - 2023-03-31

• (breaking) Switched the convention for results from apply!(Register(...), sMX) (and corresponding for sMY and sMZ). Previously the +1 eigenvector and -1 eigenvector were mapped to 1 and 0 as measurement results. This is inconvenient for boolean math and contrary to typical convection. Moving to standard convention now (+1 eigenvector corresponds to result 0). Most convenient because eigenvalue = (-1)^measurement result.
• The clipped gauge (canonicallize_clip!) now works on mixed (i.e. incomplete, i.e. non-square) tableaux

v0.6.7 - 2022-12-27

• (fix) Fixed bug in CliffordOperator(AbstractTwoQubitOperator).
• Fixes to inference failures (detected by JET).
• Significant test coverage increase.
• Significant improvement in TTFX thanks to fixes to Polyester.jl (for Julia 1.9).
• Stabilizing a few features, moving out of Experimental.NoisyCircuits
  • applynoise!
  • affectedqubits
  • NoisyGate
  • NoiseOp and NoiseOpAll
  • UnbiasedUncorrelatedNoise

v0.6.6 - 2022-12-24

• random_destabilizer(rank,nb_of_qubits) now exists to provide a random MixedDestabilizer instance of a given rank.
• Stabilizing a few features, moving out of Experimental.NoisyCircuits
  • BellMeasurement
  • mctrajectories, mctrajectory!, applywstatus!
  • CircuitStatus
• colpermute! was turned into Base.permute!. It was not documented or used previously.
• check_allrowscommute is not exported by default anymore. It was not documented or used previously.

v0.6.5 - 2022-12-23

• Minor API adjustments in preparation for releasing BPGates.jl.

v0.6.4 - 2022-12-11

• Move the API declarations to QuantumInterface.jl, a mostly namespacing package shared with QuantumOptics.jl.

v0.6.3 - 2022-09-24

• Bring the v0.6.2 performance improvements to Julia 1.7 and 1.6. Switch from using constprop to explicit static dispatch with @valbooldispatch.
• Support Julia 1.6 again.

v0.6.2 - 2022-09-22

• Performance improvements: fine tuning of constprop, eliminating a handful of common causes of dynamic dispatch.
• Drop support for Julia 1.6.

v0.6.1 - 2022-09-05

• (fix) Fix a bug in the unexported projectremoverand! that occurred due to the introduction of Tableau.

v0.6.0 - 2022-08-22

• (breaking) Split the Stabilizer object into a Stabilizer that semantically represents a state, and a general Tableau that does not carry such an interpretation. Stabilizer uses Tableau internally. stab.xzs and stab.phases property access would now fail. Use tab(stab) to get the tableau object and phases(stab) to get the phases.
• Simplify type parameters.

v0.5.9 - 2022-08-17

• Register now works with traceout! and project*rand!.

v0.5.8 - 2022-08-15

• Implement projectremoverand! which besides performing a projective measurement like projectrand! also removes the measured qubit from the tableau, returning a smaller tableau. Not yet exported in public API.

v0.5.7 - 2022-07-24

• (fix) apply!(S"XXX", P"X", [1]) and similar sparse Pauli applies were giving wrong results.
• Significant speedup of petrajectories thanks to an order of magnitude speedup in applynoise_branches(...,::UnbiasedUncorrelatedNoise).
• Expanding test suite, including base functions, Experimental.NoisyCircuits, and others. Re-establishing tests of alternative bit-packing.

v0.5.6 - 2022-07-20

• (fix) Bug-fixes to PauliMeasurement, Reset, and Register, detected by JET.

v0.5.5 - 2022-07-05

• (breaking fix) CliffordOperator constructor called on a square tableau occasionally resulted in incorrect results due to row-reordering during canonicalization.
• Continuing static analysis fixes thanks to JET.
• Optimization of canonicalize_clip!, now resulting in much fewer allocations.

v0.5.4 - 2022-07-03

• Start using JET.jl for static analysis during CI.
• The MixedDestabilizer constructor now accepts over redundant tableaux (tableaux with redundant rows).
• Resolved multiple method ambiguities and started testing for them with Aqua.jl in CI.

v0.5.3 - 2022-06-11

• (fix #60) enumerate_clifford was broken due to an earlier refactor in rowswap!

v0.5.2 - 2022-06-08

• Implement the clipped gauge canonicalization canonicalize_clip! and related functions.
• Implement entanglement_entropy.

v0.5.1 - 2022-06-02

• (fix #57 c83f85f) - Graph vertex indices and qubit indices in tableaux were mismatched.

v0.5.0 - 2022-05-19

• (breaking) Rename all pre-defined tableaux to have a t prefix. e.g., CNOT→tCNOT, in order to distinguish them from "symbolic" operators like sCNOT.
• (breaking) Rename CliffordId to tId1 to match the naming style of sId1.
• Implement enumerate_cliffords, enumerate_phases, symplecticGS used for the enumeration of all Clifford operations over given number of qubits.
• Implement convertors from symbolic operators to dense tableau operators: CliffordOperator(sCNOT) now gives tCNOT which acts equivalently to sCNOT(1,2).
• Implement project[X|Y|Z]rand! as a simpler interface to project! with automatic randomization of measurement phases.
• Implement sMX/sMY/sMZ symbolic measurement operations that can be used with apply!. Use projectrand! internally.
• (breaking) Cleanup of NoisyCircuits
  • The experimental module NoisyCircuits now supports only MixedDestabilizer and Register.
  • Register is moved out of NoisyCircuits. Used with sMX/etc to store classical bit results during circuit evolution.
  • SparseGate is moved out of NoisyCircuits.
  • Reset is moved out of NoisyCircuits.
  • DenseMeasurement is renamed PauliMeasurement and moved out of NoisyCircuits.
  • DenseGate is removed (just use any dense CliffordOperator).
  • SparseMeasurement is removed (just use sMX, sMY, sMZ). Due to this we lost the functionality of measuring more than one but less than all qubits.
  • applyop! is renamed to applywstatus! and simplified.
  • applyop_branches is renamed to applybranches and simplified.

v0.4.3 - 2022-03-24

• Implement trusted_rank that returns rank for states that support it and length for others (e.g. Stabilizer).
• Implement length for [Mixed]Destabilizer.
• Clean up code repetition between project! and projectX/Y/Z!. Issue #40
• More conversion constructors between different tableau types.
• Implement pre-compilation examples (again) for julia 1.9+.
• generate! does not needlessly allocate anymore, helping project! on Stabilizer. Issue #39

v0.4.2 - 2022-03-22

• project! does not needlessly allocate anymore on MixedDestabilizer. Issue #39, PR #41

v0.4.1 - 2022-03-21

• apply_single_* are not exported anymore, as sX/sY/sZ are cleaner choices.
• Faster single-qubit projections with projectX!, projectY!, projectZ!.
• Move circuit plotting with Quantikz.jl to QuantumCliffordPlots.jl
• Random states with zeroed phases with phases=false.
• Pre-compilation and inference cleanup (useful for Julia 1.8+).
• Switch from LoopVectorization.jl to SIMD.jl for fine-tuning of performance (and coincidentally, better TTFX).

v0.4.0 - 2022-01-27

• Permit whitespace separators in the S string macro.
• (breaking) project! now returns anticom_index=rank instead of anticom_index=0 in the case of projection operator commuting with all stabilizer rows but not in the stabilizer group. If your code previously had anticom_index!=0 checks, now you might want to use anticom_index!=0 && anticom_index!=rank. Conversely, treating projective measurements in general code is now much simpler.
• (fix #31 b86b30e2) Dependent on the above, a bug fix to Experimental.DenseMeasurement when the measurement operator commutes with but is not in the stabilizer.
• A new expect function to find the expectation value of a Pauli measurement for a given stabilizer; simpler to use compared to project!.
• (fix #28 9292333a) Fix a rare bug in reset_qubits!(::MixedDestabilizer).

v0.3.0 - 2022-01-10

• dot and logdot for calculating dot products between Stabilizer states.
• Initial support for graph states, e.g., conversion to and from arbitrary Stabilizer state.
• (breaking) Implemented Makie.jl plotting recipes in the QuantumCliffordPlots.jl package, which now also stores the Plots.jl recipes.
• Much faster tensor product of states.
• (breaking) CliffordColumnForm has been completely removed. Only CliffordOperator now exists.
• (breaking) random_singlequbitop was removed, as it was using CliffordColumnForm. random_clifford1 is a partial alternative.
• Drop Require to improve import times.
• Simplify internal data layout for Stabilizer.
• (fix 4b536231) Fixed bug in generate! that occurs on small IZ Paulis.
• Some performance improvements related to allocations in apply!.

v0.2.12 - 2021-12-32

• apply! is now multi-threaded thanks to Polyester.
• Named Clifford operators with much-faster special-cased apply! are implemented.
• An assortment of new constructors are available to ease the conversion between data structures.
• Drop support for Julia 1.5.

Older - before 2021-10-28 unrecorded