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)

Special thanks to this release contributors:

@aebrahimi
@inmzhang
@qec-pconner
@dougthor42
@nelimee
@mghibaudi
@folded
@AlexBourassa