v1.14.0 - More Flows

Flagship changes:

• Added stim.Circuit.flow_generators for finding the stabilizer flows of a circuit.
• Added stim.Circuit.time_reversed_for_flows for reversing circuits containing resets and measurements.
• Added sinter.Sampler for customizing sinter to more general Monte Carlo sampling tasks.

Notable changes:

• Added stim.Circuit.flow_generators
• Added stim.Circuit.insert
• Added stim.Circuit.pop
• Added stim.Circuit.time_reversed_for_flows
• Added stim.Circuit.to_crumble_url
• Added stim.Circuit.to_quirk_url
• Added stim.CircuitInstruction.num_measurements
• Added stim.CircuitInstruction.target_groups
• Added stim.CircuitRepeatBlock.num_measurements
• Added stim.DemInstruction.target_groups
• Added stim.FlipSimulator.clear
• Added stim.FlipSimulator.copy
• Added stim.GateData.hadamard_conjugated
• Added stim.GateData.is_symmetric_gate
• stim.CompiledDetectorSampler.sample gained obs_out=None and dets_out=None arguments
• stim.Circuit.to_crumble_url gained skip_detectors=False and mark=None arguments
• stim.CircuitInstruction.__init__ gained the ability to parse single lines from a stim circuit file
• stim.DemInstruction.__init__ gained the ability to parse single lines from a detector error model file
• stim.DemTarget.__init__ gained the ability to parse targets from detector error mode files (e.g. stim.DemTarget("D2"))
• In stim's gate data, the generalized inverse of R{X,Y,Z} is now M{X,Y,Z} instead of MR{X,Y,Z}
• Added support for viewing and editing detectors and observables in crumble
• Reduced the amount of copying during sampling, speeding up detector sampling by around 25%
• Began collecting papers with available stim circuits at doc/circuit_data_references.md

Notable changes to diagrams:

• stim.Circuit.diagram gained a rows=None argument, for controlling layout
• Added "tick #" labels to timeslice diagrams
• Improved stim.Circuit.detector_error_model error messages to suggest code for drawing a diagram of the problem
• Match graph diagrams now highlight observable-flipping hyper errors (purple instead of blue)
• In match graph diagrams, nodes with observable-crossing boundary edges are now colored red instead of black
• The detector indicator in 3d match graph diagrams is not flat anymore, so it's easier to see from all angles
• stim.Circuit.diagram("detslice") now draws a pink circle where bad detectors anticommute with dissipative operations, instead of raising an exception
• Added -html variants of svg diagrams (e.g. circuit.diagram("detslice-html")
  • Outputs a little HTML viewer of the svg diagram, with a resizing tab, which works better in notebooks than a raw SVG
• detslice diagrams no longer raise an exception for circuits with anticommuting detectors. Instead, a diagram highlighting the anticommutation is returned.
• Improved the heuristics for using Bezier curves instead of straight lines

Notable changes to sinter:

• Added sinter.Sampler
• Added sinter.CompiledSampler
• Added named sinter sampler perfectionist
• Any sinter decoder can now indicate shots to discard, by adding an extra byte column to the returned observable data (0=keep, else=discard)
• sinter collect now distributes workers evenly over tasks, instead of focusing on one task at a time
• sinter collect now never switches a worker to a new task until their current task is done
• Added sinter plot --point_label_func command line argument
• Added sinter plot --dpi for increasing resolution of plots
• Expanded sinter plot --group_func to take dictionary arguments
  • The "color" key of the dictionary controls color groups
  • The "linestyle" key of the dictionary controls linestyle groups
  • The "marker" key of the dictionary controls marker groups
  • The "label" key of the dictionary controls labels of curves in the legend
  • The "sort" key of the dictionary controls order of curves in the legend
• sinter collect --processes now defaults to "auto" (number of CPUs) if not specified
• sinter plot --show is now implied when --out isn't specified
• Added sinter plot --preprocess_stats_func for specifying a python expression to process stats before plotting
• Added sinter.TaskStats.with_edits
• Added a safety check to sinter.TaskStats.__add__, raising an exception if decoder/json_metadata disagree despite strong ids agreeing
• Added supported decoder "hypergraph_union_find"
• Added supported decoder "mw_parity_factor"

Notable bug fixes:

• Fixed HERALDED_PAULI_CHANNEL_1 permuting X/Y/Z/ error channels 😱😱😱
• Fixed various internal methods not correctly propagating Pauli terms through MXX, MYY, and MZZ instructions that operated on the same qubit more than once 😱
• Fixed stim.Circuit.with_inlined_feedback incorrectly ordering operations fused by the removal of a feedback operation
• Fixed stimcirq.cirq_circuit_to_stim_circuit not adding TICKs from multi-moment CircuitOperation blocks
• Fixed MPAD targets counting towards stim.Circuit.num_qubits
• Fixed stim.PauliString.{before,after} not supporting SPP and SPP_DAG
• Fixed stim.PauliString.before refusing to cross reset gates
• Fixed sinter failing to create plots for data points with extremely large shot counts
• Fixed stim.Tableau.from_stabilizers error messages claiming stabilizers were redundant when they actually anticommuted
• Fixed incompatibility with numpy v2
• Fixed incompatibility with new version of scipy (the linear regression type moved)

v1.13.0 - Freed Flows

Flagship changes:

• Added support for representing and verifying stabilizer flows (stim.Flow, stim.Circuit.has_flow, stim.Circuit.detecting_regions)

Notable changes:

• New top-level methods/types:
  • Added stim.Flow class for representing stabilizer flows
  • Added stim.target_pauli
  • Added stim.target_combined_paulis
  • Added stim.PauliStringIterator
• New stim.Circuit methods:
  • Added stim.Circuit.decomposed
  • Added stim.Circuit.detecting_regions
  • Added stim.Circuit.to_qasm
  • Added stim.Circuit.has_flow
  • Added stim.Circuit.has_all_flows
  • Added stim.Circuit.shortest_error_sat_problem
  • Added stim.Circuit.likeliest_error_sat_problem
• New stim.GateData methods:
  • Added stim.GateData.{__eq__,__ne__,__repr__,__init__,__str__}
  • Added stim.GateData.flows
  • Added stim.GateData.generalized_inverse
  • Added stim.GateData.inverse
• New stim.PauliString methods:
  • stim.PauliString.__init__ now allows sparse syntax (like stim.PauliString("-X50*Z99"))
  • Added stim.PauliString.iter_all
  • Added stim.PauliString.pauli_indices
  • Added stim.PauliString.weight
  • Sped up stim.PauliString.{after,before} by over 10x
• New stim.Tableau methods:
  • Added stim.Tableau.to_circuit("graph_state")
  • Added stim.Tableau.to_circuit("mpp_state")
  • Added stim.Tableau.to_circuit("mpp_state_unsigned")
  • Added stim.Tableau.to_stabilizers
  • Sped up stim.Tableau.from_stabilizers by over 200x
• New stim.FlipSimulator methods:
  • Added stim.FlipSimulator.broadcast_pauli_errors
• New gates:
  • Added CZSWAP gate (with alias SWAPCZ)
  • Added SPP gate (generalized S gate that applies to Pauli products)
  • Added SPP_DAG (inverse of SPP)
• Added sinter.FusionBlossomCompiledDecoder, speeding up decoding with fusion blossom
• Added sinter plot --ymax command line argument
• stimcirq now converts PAULI_CHANNEL_2 into cirq's native asymmetric channel
• Added Bloch Rotation (Euler angles) to gate documentation
• Added prebuilt wheels for python 3.12
• Tweaked sinter plot's marker/color ordering to increase how many curves are needed to get two curves that look similar

Notable bug fixes:

• Fixed sinter plot --xaxis only applying to one subplot, instead of all subplots
• Fixed build-from-source not working on IBM PowerPC
• Fixed HERALDED_PAULI_CHANNEL_1 targeting the wrong qubits (this fix was also backported to 1.12.1)
• Fixed stim.Circuit.explain_dem_errors not supporting all gates
• Fixed crumble not allowing e and q to repeatedly move between layers when held down
• Fixed crumble not falling back to an emulated clipboard when clipboard permissions weren't granted

Special thanks to this release's contributors:

@fdmalone
@markturner289
@mmcewen-g
@nickdgardner
@noajshu
@tomirendo

v1.12.1 - Fix HERALDED_PAULI_CHANNEL_1

Notable changes:

• Add python 3.12 to the versions with prebuilt wheels

Bug fixes:

• Fixed HERALDED_PAULI_CHANNEL_1 targeting fixed indices instead of the given qubits
  • For example, HERALDED_PAULI_CHANNEL_1(0.1) 2 5 3 was behaving like HERALDED_PAULI_CHANNEL_1(0.1) 0 1 2

v1.12.0 - Foreseen Flips

Flagship changes:

• Added support for heralded erasures
• Added stim.FlipSimulator for tracking batches of Pauli flips through circuits
• Doubled sinter's sample throughput on high core count machines

Notable changes to stim:

• Added gates: HERALDED_ERASE, HERALDED_PAULI_CHANNEL_1, MXX, MYY, MZZ, MPAD
• Added top-level method stim.gate_data
• Added class stim.GateData
  • Properties: aliases, is_noisy_gate, is_reset, is_single_qubit_gate, is_two_qubit_gate, is_unitary, name, num_parens_arguments_range, produces_measurements, tableau, takes_measurement_record_targets, takes_pauli_targets, unitary_matrix
• Added class stim.FlipSimulator
  • Methods: __init__, do, get_detector_flips, get_measurement_flips, get_observable_flips, peek_pauli_flips, set_pauli_flip
  • Properties: batch_size, num_detectors, num_measurements, num_observables, num_qubits
• Added stim.Circuit.count_determined_measurements
• Added stim.Circuit.num_ticks
• Added stim.Circuit.reference_sample
• Added stim.CircuitRepeatBlock.name (for duck typing vs stim.CircuitInstruction)
• Added stim.DemRepeatBlock.type (for duck typing vs stim.DemInstruction)
• Added stim.GateTarget.pauli_type
• Added stim.GateTarget.qubit_value
• Added stim.TableauSimulator.postselect_observable
• Added optional reference_sample argument to stim.Circuit.compile_sampler
• Made stim.PauliString.{after,before} much less picky
• Improved performance of stim.CompiledDetectorSampler by ~30% under repetitive usage by caching more internal objects
• Circuit-to-dem conversion now adds the probabilities of indistinguishable cases within a disjoint error channel, instead of Bernoulli-adding them
• Added the stim convert command for converting between shot file formats

Notable changes to sinter:

• sinter now has an API reference
• sinter now has a command line reference
• Added sinter.Decoder.compile_decoder_for_dem method for custom decoders to implement
  • Improves performance ~2x on high core count machines by avoiding disk usage
• Added a shorthand to sinter plot: use m.key instead of metadata.get("key", None) in *_func arguments
• Added square root scales to sinter plot (example: --xaxis "[sqrt]qubit count")
• Added an optional custom_counts column to sinter's CSV format
• Added auto option to use all processes (sinter collect --processes=auto)
• Added sinter plot --line_fits
• Added sinter plot --xmax
• Added sinter plot --xmin
• Added sinter plot --failure_values_func
• Added sinter plot --subtitle with {common} macro
• Added sinter collect --count_detection_events
• Added sinter collect --count_observable_error_combos
• Added sinter collect --allowed_cpu_affinity_ids
• Added sinter combine --strip_custom_counts
• Added sinter plot --custom_error_count_keys
• Added sinter.log_binomial
• Added sinter.log_factorial
• Added sinter.read_stats_from_csv_files
• Added sinter.{AnonTaskStats,TaskStats}.custom_counts
• Added sinter.Task.circuit_path field for specifying circuits by filepath
• Added arguments count_observable_error_combos=False and count_detection_events=False to sinter.{iter_collect,collect}

Notable changes to crumble:

• Added support for MPP operations
• Added example circuits

Notable bug fixes

• Fixed stimcirq.__version__ and sinter.__version__ not existing
• Fixed stimcirq.cirq_circuit_to_stim_circuit choking on tagged operations
• Fixed stimcirq.cirq_circuit_to_stim_circuit not putting repeat blocks in their own moment
• Fixed triggering numpy bool8 deprecation warnings
• Fixed documentation not mentioning how to do pauli feedback
• Fixed a failure in stim m2d related to appending observables crossing a simd boundary when --obs_out was used
• Fixed some corner cases where sinter.better_sorted_str_terms produced incomparable values
• Fixed cmake install doing nothing
• Fixed some sinter plot crashes on degenerate data
• Fixed several sinter classes not having evaluatable reprs
• Fixed stim.Tableau.inverse returning invalid results when the tableau's representation included size padding
• Fixed HTML diagrams not being isolated from each other in notebooks (wrapped them all in iframes)
• Fixed stimzx example project discarding sign information of external stabilizers
• Fixed stim.Circuit.shortest_graphlike_error and friends not working if there were more than 64 observables

Special thanks to this release's contributors:

@AlexBourassa
@fdmalone
@markturner289
@oon3m0oo
@viathor
@justinledford

v1.11.0 - Dancing Diagrams

Major changes:

• Added prototype interactivate diagrams for circuits. See the crumble README.

Breaking changes:

• stim.DetectorErrorModel.shortest_graphlike_error now defaults ignore_ungraphlike_errors to True instead of False. Also, it now actually ignores all ungraphlike errors when set to True.

General additions and improvements:

• Added a new gate: CXSWAP (and SWAPCX). This gate is KAK-equivalent to the ISWAP, but avoids mixing X and Z terms, which is useful when creating/debugging circuits intended to use ISWAP-like interactions.
• Added a new diagram type "interactive". Interactive diagrams are a HTML pages containing "crumble".
• Added stim.Circuit.inverse
• Added stim.Circuit.with_inlined_feedback
• Added stim.TableauSimulator.measure_pauli_string
• Gave the project a logo
• Simplified the names of diagram types (the old names still work but are no longer listed in documentation)
• Added separate_observables=False argument to stim.read_shot_data_file
• Added unsigned=False argument to stim.PauliString.from_unitary_matrix
• Added stim.Tableau.x_sign, stim.Tableau.y_sign, stim.Tableau.z_sign helper methods
• Added stim.TableauSimulator.depolarize1, stim.TableauSimulator.depolarize2, stim.TableauSimulator.x_error, stim.TableauSimulator.y_error, stim.TableauSimulator.z_error
• Added a --ran_without_feedback command line option to stim m2d
• Added stim.PauliString.before, stim.PauliString.after

Diagram improvements:

• Detector slice diagrams now use colors that are more color-blind friendly
• Added new diagram type detslice-with-ops-svg which overlays operations over the detector slice diagram
• The type argument for .diagram methods is no longer keyword-only
• The tick argument for .diagram methods can now be set to a range(start, end), producing a diagram containing each tick in the range as a sub-diagram
• Detector slice diagrams now prefer shapes that have mirror symmetry, when choosing how to draw a stabilizer
• Detector slice diagrams now switch to using bezier curves when stroking between colinear points, to disambiguate which points are vertices and which points are skipped
• Increased the initial size used for the 3d model viewer and the svg viewer
• Improved the initial camera position used by the 3d model viewer to better frame the model
• Increased the font sizes used for gates in SVG diagrams, so they better fill their boxes
• Detector slice diagrams can now be filtered by stim.DemTarget (to slice observables in addition to detectors, include observable targets in the filter)
• SVG diagrams now group elements, making them easier to touch up afterwards in image editors

Sinter improvements:

• Added --postselected_detectors_predicate to sinter collect, generalizing --postselect_detectors_with_non_zero_4th_coord
• It's now possible to specify custom decoders
  • Added sinter.Decoder class
  • Added a custom_decoders arg to sinter.collect, sinter.iter_ollect, sinter.predict_on_disk, sinter.predict_observables_bit_packed
  • Added a --customer_decoders_module_function command line argument to sinter collect
• sinter predict can now be given --metadata_func auto instead of --metadata_func "sinter.comma_separated_key_values(path)"
• Added command line arguments to sinter plot:
  • --y_func
  • --y_axis
  • The expression given to --plot_args_func now has access to several more values: stat, stats, decoder, metadata, and strong_id`.
  • The plot_args_func argument of sinter.plot methods can now take a third argument, stats, the list of stats in the curve
• Discard rate diagrams now include more Y axis indicators
• sinter combine now sorts its output
• Added --order preserve|metadata|error option to sinter combine

Bug fixes:

• Due to a mysterious crash in collab, the AVX build has been temporarily disabled.
• Fixed generating degenerate diagrams when circuits had no coordinate data
• Fixed stimcirq.StimSampler not working on cirq circuits containing repeated keys
• Fixed stimcirq.SweepPauli._resolve_parameters_ failing to resolve strings, and not specifying _parameter_names_
• Fixed a typo in stim.PauliString's documentation. The allowable signs are [1, -1, 1j, -1j].
• Fixed a quadratic overhead caused by iteratively growing the tableau simulator's state
• Fixed sinter crashing on shutdown on windows, due to not waiting for workers to die before deleting their files
• Fixed sinter ignoring error codes returned from pymatching.
• Fixed stim.Tableau.from_stabilizers not verifying that the given stabilizers actually commute
• Related: pymatching fixed a bug where it was linking an older version of stim that opened binary files in text mode, causing sinter to fail when using pymatching on windows.

v1.10.0 - Inviting Interop

Flagship changes:

• Use open source decoders that are 100x to 1000x faster than before! (pymatching v2 and fusion_blossom)
• Produce 2d and 3d diagrams of circuits and detector error models, with built-in viewers for Jupyter notebooks!
• Sample directly from detector error models. Record the errors that occurred, edit them, and play them back!

Notable changes:

• Added stim.Circuit.diagram
  • Added diagram type "detector-slice-text"
  • Added diagram type "detector-slice-svg"
  • Added diagram type "match-graph-svg"
  • Added diagram type "match-graph-3d"
  • Added diagram type "match-graph-3d-html"
  • Added diagram type "timeline-text"
  • Added diagram type "timeline-svg"
  • Added diagram type "timeline-3d"
  • Added diagram type "timeline-3d-html"
• Added stim.DetectorErrorModel.diagram
  • Added diagram type "match-graph-svg"
  • Added diagram type "match-graph-3d"
  • Added diagram type "match-graph-3d-html"
• Added methods to stim.PauliString:
  • stim.PauliString.from_numpy
  • stim.PauliString.from_unitary_matrix
  • stim.PauliString.to_numpy
  • stim.PauliString.to_tableau
  • stim.PauliString.to_unitary_matrix
• Added methods to stim.TableauSimulator:
  • stim.TableauSimulator.__init__ now has an optional seed argument
  • stim.TableauSimulator.set_state_from_stabilizers
  • stim.TableauSimulator.set_state_from_state_vector
  • stim.TableauSimulator.do now accepts stim.CircuitInstruction and stim.CircuitRepeatBlock
• Added methods to stim.Tableau:
  • stim.Tableau.iter_all
  • stim.Tableau.from_circuit
  • stim.Tableau.from_numpy
  • stim.Tableau.from_stabilizers
  • stim.Tableau.from_state_vector
  • stim.Tableau.from_unitary_matrix
  • stim.Tableau.to_circuit
  • stim.Tableau.to_numpy
  • stim.Tableau.to_pauli_string
  • stim.Tableau.to_state_vector
• Added methods to stim.DetectorErrorModel:
  • stim.DetectorErrorModel.flattened
  • stim.DetectorErrorModel.rounded
  • stim.DetectorErrorModel.compile_sampler
• Added stim.CompiledDemSampler class with methods:
  • stim.CompiledDemSampler.sample
  • stim.CompiledDemSampler.sample_write
• Improvements to sinter
  • Added support for pymatching v2
  • Added support for fusion_blossom decoder
  • Added flag --title to sinter plot
  • Added flag --miny to sinter plot
  • Added flag --plot_args_func to sinter plot
  • Added flag --failure_units_per_shot_func to sinter plot
  • Added flag --failure_unit_name argument to sinter plot
  • Added grid lines to the plots made by sinter plot
  • Added filter_func, failure_units_per_shot_func, and failure_unit_name arguments to sinter.plot_error_rate and sinter.plot_discard_rate
  • Added sinter.predict_observables method
  • Added ability to discard shots based on observables being mispredicted
    • Added --postselected_observables_predicate flag to sinter collect
    • Added sinter.Task.postselected_observables_mask field
    • Added postselected_observable_mask argument to sinter.sample_decode
• Added stim diagram command for producing diagrams, with flags --in, --type, --out, --tick, --remove_noise, --filter_coords.
• Added stim sample_dem command for directly sampling from detector error model files, with flags --err_out, --err_out_format, --in, --obs_out, --obs_out_format, --out, --out_format, --replay_err_in, --replay_err_in_format, --seed, --shots, --err_out, --err_out_format, --replay_err_in, --replay_err_in_format.
• Added separate_observables=False argument to stim.CompiledDetectorSampler.sample
• Added bit_packed=False argument to stim.CompiledDetectorSampler.sample
• Added bit_packed=False argument to stim.CompiledMeasurementSampler.sample
• Deprecated stim.CompiledDetectorSampler.sample_bit_packed
• Deprecated stim.CompiledMeasurementSampler.sample_bit_packed

Notable bug fixes:

• Fixed stim.Circuit.flattened not fusing all operations
• Fixed stim.Circuit.without_noise not fusing all operations
• Fixed PAULI_CHANNEL_2 not being marked as targeting pairs of qubits
• Fixed sinter's internal python files not being marked as private, so they don't appear as autocomplete suggestions
• Fixed stim.Circuit.detector_error_model failing when errors affected more than 15 detectors (unless decompose_errors=True)
• Fixed stim.Circuit.without_noise not making independent copies of the operations (!)
• Fixed sinter only sampling using the first decoder given to it, instead of all decoders, when given multiple decoders
• Fixed not redirecting stdout and stderr to python's when calling stim.main
• Fixed unnecessary overhead in the conversion to/from numpy arrays (10x faster for small arrays)
• Fixed a segfault and bad parsing logic in stim.read_shot_data_file (!). Fuzz tested the read/write methods against the python reference methods to avoid this happening again.

Notable dev changes:

• Fixed files being opened in text mode instead of binary mode, resulting in bad parsing/serialization on Windows due to \n bytes being turned into \r\n and vice versa.
• Templatized classes like simd_word so AVX and SSE code can coexist in the same binary
• Added stim_python_bindings cmake target
• The cmake build now uses file lists which can be regenerated using a script
• Added dev/ directory for scripts
• File lists used by cmake are now generated automatically instead of maintained manually
• The polyfill simd_word that uses 64 bit words now only uses one word instead of two (reducing padding overhead)
• To allow supporting a larger variety of decoders, sinter no longer includes each decoder in its requirements. Decoders need to be installed separately to use them.
• Added -fPIC to libstim cmake target
• Sinter now passes most information via the disk instead of through the multiprocessing API. This reduced the workload on the manager and the startup costs of batches, but made it much more disk limited on high core count machines.
• The API reference no longer shows deprecated methods (these methods are still listed in the .pyi stubs file)
• All doc strings now wrap at 80 characters, and this is enforced by continuous integration.
• The command line reference documentation has been substantially improved (e.g. flag information now grouped with the command instead of separate)
• Added python 3.11 support and OSX ARM support to the set of prebuilt wheels

v1.9.0 - Sintered Samples

Flagship changes:

• Released sinter, which uses stim and pymatching to perform multicore Monte Carlo sampling of error correction circuits.
• Added a python stub file (stim/__init__.pyi) to improve autocompletion in IDEs.

Breaking changes:

• The "ptb64" format now requires the shot count to be a multiple of 64, both when reading and when writing. (Previously, missing shots resulted in padding with zero'd data, which created a very easy way to get bad data when reading if the number of shots was not known.)
• The default value of stim.Circuit.shortest_graphlike_error's argument ignore_ungraphlike_errors has changed from from False to True. (Setting it to False can use "remnant edges" that only appear as components of decomposed errors, and so do not correspond to a single physical error mechanism.)

Notable changes:

• New global methods:
  • stim.main
  • stim.read_shot_data_file
  • stim.write_shot_data_file
• New stim.DetectorErrorModel methods:
  • stim.DetectorErrorModel.to_file
  • stim.DetectorErrorModel.from_file
• New stim.Circuit methods:
  • stim.Circuit.without_noise
  • stim.Circuit.flattened
  • stim.Circuit.search_for_undetectable_logical_errors
  • stim.Circuit.to_file
  • stim.Circuit.from_file
• New stim.TableauSimulator methods:
  • stim.TableauSimulator.c_xyz
  • stim.TableauSimulator.c_zyx
  • stim.TableauSimulator.cx
  • stim.TableauSimulator.do_circuit
  • stim.TableauSimulator.do_pauli_string
  • stim.TableauSimulator.do_tableau
  • stim.TableauSimulator.h_xz
  • stim.TableauSimulator.num_qubits
  • stim.TableauSimulator.peek_x
  • stim.TableauSimulator.peek_y
  • stim.TableauSimulator.peek_z
  • stim.TableauSimulator.postselect_x
  • stim.TableauSimulator.postselect_y
  • stim.TableauSimulator.postselect_z
  • stim.TableauSimulator.reset_x
  • stim.TableauSimulator.reset_y
  • stim.TableauSimulator.reset_z
  • stim.TableauSimulator.zcx
  • stim.TableauSimulator.zcy
  • stim.TableauSimulator.zcz
• New stim.Tableau methods:
  • stim.Tableau.to_unitary_matrix
• New method options:
  • obs_path=None and obs_format for stim.CompiledDetectorSampler.sample_file
  • obs_path=None and obs_format for stim.CompiledMeasurementsToDetectionEventsConverter.convert_file
  • ignore_decomposition_failures=False for stim.Circuit.detector_error_model
  • block_decompose_from_introducing_remnant_edges=False option for the stim.Circuit.detector_error_model
  • bit_pack_result=False for stim.CompiledMeasurementsToDetectionEventsConverter.convert
• Functional changes:
  • Error analysis now attempts to avoid introducing remnant edges unless absolutely necessary (improves detector error models)
  • Error analysis now supports ELSE_CORRELATED_ERROR instructions as long they occur in contiguous blocks started by a CORRELATED_ERROR
  • The stim python package now includes the stim command line tool. Much easier than building it for yourself.
  • The floating point accuracy of stim.TableauSimulator.state_vector has been substantially improved (e.g. all zeros are now exact)
  • The method signatures shown in the API reference are now more accurate, matching the ones in __init__.pyi

Bug fixes:

• Worked around the pseudo random number generator state being duplicated when using multiprocessing with start method "fork". Samplers now seed from external entropy when constructed, instead of using entropy acquired at startup.
• Fixed various reported build failures related to MacOS and Apple M chips.
• Fixed setup.py not forcing UTF8 encoding when loading README.md, causing crashes on systems configured to use other encodings by default.
• Fixed stimcirq not understanding probabilistic cirq.DensePauliString gates.
• Worked around an issue where pytest gives useless failure messages for asserts involving stim objects.
• Fixed an infinite loop in stim.Circuit.get_detector_coords.
• Fixed complex indices like stim.Circuit()[1j] crashing the python interpreter (by switching to latest version of pybind11).
• Fix loop folding during error analysis incorrectly folding loops with observables including measurements from only the last few iterations
• Fixed a segfault in measurement-to-detection-event conversion related to failing to ignore noise channels
• Fixed a bug in measurement-to-detection-event conversion where some OBSERVABLE_INCLUDE instructions were being forgotten

v1.8.0 - Explorable Errors

Flagship changes:

• Search for smallest logical errors directly from a circuit
• Find circuit errors that explain detector error model symptoms
• Helpful error messages when detector error model extraction fails
• Better compatibility with cirq

Notable changes:

• Added stim.Circuit.shortest_graphlike_error for finding the smallest set of physical errors that can cause an undetected logical error (as long as they each have at most two detection events)
• Added stim.Circuit.explain_detector_error_model_errors for listing how detector error model symptoms match up with physical circuit error mechanisms
• When stim.Circuit.detector_error_model fails due to an anti-commuting detector or observable, the error message now describes in great detail the involved detectors, qubits, and error sensitivities
• Added several dataclasses for representing results from stim.Circuit.explain_detector_error_model_errors
• Added stim.Circuit.get_detector_coordinates
• Added stim.Circuit.get_final_qubit_coordinates
• Added stim.DetectorErrorModel.get_detecetor_coordinates
• Added stim.Circuit.append as a shorter more pythonic alias for append_operation
• stim.Circuit.append now allows the targets argument to be a single target, instead a list of targets
• stim.Circuit.append verifies that a probability argument is given when appending noisy gates
• stimcirq now converts DETECTOR annotations (via stimcirq.DetAnnotation)
• stimcirq now converts OBSERVABLE_INCLUDE annotations (via stimcirq.CumulativeObservableAnnotation)
• stimcirq now converts SHIFT_COORDS annotations (via stimcirq.ShiftCoordsAnnotation)
• stimcirq now converts REPEAT blocks (via cirq.CircuitOperation)
• stimcirq now converts MPP measurements (via cirq.PauliMeasurementGate) (inverted results not yet supported due to quantumlib/Cirq#4814)
• stimcirq now converts operations controlled by sweep targets (via stimcirq.SweepPauli)
• stimcirq now supports cirq json serialization (via stimcirq.JSON_RESOLVER and stimcirq.JSON_RESOLVERS_DICT)
• Fixed stim.CircuitInstruction, stim.GateTarget, stim.DemTarget, stim.DemInstruction not being hashable
• Improved documentation of the file formats for sample results
• Fixed measurement-to-detection conversion going into an infinite loop for circuits with no measurements when using file format b8
• Development versions of stim are now automatically uploaded to pypi when changes are merged into main

v1.7.1 - Installation Iteration

• Fix using AVX instructions as part of checking if AVX instructions can be used (see #179)
• Fix the source distribution (sdist) not including header files

v1.7.0 - Immediate Installation

Flagship changes:

• Stim's python package is now pre-built, reducing install time from >5 minutes to a few seconds
• Fixed error analysis evaluating overlapping MPP targets in the wrong order, creating bad detector error models

Notable changes:

• Added pickling support to stim.Tableau, stim.Circuit, stim.PauliString, and stim.DetectorErrorModel
• Added stim.DetectorErrorModel.shortest_graphlike_error for quickly finding simple low weight errors and upper bounding code distance
• Added several small handy stim.DetectorErrorModel methods:
  • append
  • approx_equals
  • num_errors
  • + and += (concatenation)
  • * and *= (repetition)
• Added stim.Circuit.approx_equals
• Fixed circuit.append_operation allowing NaN probabilities which could then cause crashes