Perceval Files

After a long wait, Perceval has finally reached version 1!

New features and reasons to upgrade

• The user documentation has been completely revamped.

  • Its improved structure is more natural, especially for newcomers,
  • The tutorials section was split in lessons divided into three levels (beginner, advanced and expert),
  • A particular care was given to Perceval and exqalibur code reference which now covers all existing features!

• It is now possible to send Experiments containing feed-forward to the Cloud. Please note that only a limited list of platforms can handle feed-forward (at the time of its release, only "sim:slos" has this capability).

• Noisy simulations were optimised a lot, through an improved preprocessing of noisy input states, the use of light-weight FockState representation during computations and an improved algorithm. It is now consuming way less memory and shows speed-ups up to 50x on larger noisy simulations.

Improvements

• CircuitOptimizer now supports an initial guess
• A Herald can be added on only one side of an Experiment, making it asymmetrical (user input state and output state won't have the same size anymore)
• Better probability threshold management in chained tensor products of distributions
• Use herald values during an imperfect Detector simulation
• Heralds and PostSelect are now transmitted between simulation layers for LC and TD components
• Optimized usage of an FSMask in SLAP
• Optimized the SLAP.prob_distribution call
• Optimized the Source model algorithm (by moving it to exqalibur)
• NoiseModel now provides pythonic access to its attributes
• A request payload may now be generated without connecting to a Cloud provider
• Enhanced Scaleway provider code

• Shor's algorithm example notebook has been modernised

• Rendering

• pdisplay handles BSSamples

• Sped up the rendering of large SVDistribution

• Remote computing

• Perceval now checks a new constraint from remote platforms, telling whether they can handle multiple input photons per mode

• Read RemoteProcessor.status property to know the current status of the corresponding remote platform
• Add field cloud_maximal_job_count to RemoteConfig, limiting the number of concurrent Job run at once when calling JobGroup.run_parallel
• JobGroup.list_existing() method was renamed to list_locally_saved(), for clarity
• The behaviour of get_results is now consistent for failed jobs (LocalJob or RemoteJob).

Bug fixes

• Experiment composition

• When composing two experiments or processors, the right-hand-side detectors now have priority

• Adding a single component to an Experiment on non-consecutive modes correctly applies an inverted permutation after it

• Circuit and Processor rendering

• Modes are now rendered below the input ports

• Fixed a bug where a subcircuit and its container box would be shifted

• Fixed a bug in specific feed-forwarded circuits rendering

• Fix handling of min_detected_photons in the NoisySamplingSimulator

• Fix Expression.fixed property
• Fix a crash that could occur in Clifford & Clifford 2017 sampling back-end
• Internal logger can now be setup to write in a file at a path containing non-ASCII characters
• A Job does not forget its name anymore when reloaded from a JobGroup
• Fix the result of PS.definition()

Breaking changes

With the release of Perceval version 1 comes a list of updated features and syntax. Here's a list of the major potential code breaks:

• To achieve large performance gains in noisy simulations, the FockState class was split into three. While the pcvl.BasicState retains most of its versatility, user code might be broken by this code.
• In some computations, physical_perf and logical_perf scores have been merged into a global_perf
• Gate based to LO circuits converters were moved from Perceval to a new package perceval-interop. Read its documentation.

A detailed documentation on how to update your Perceval code to version 1 is available here: https://perceval.quandela.net/docs/v1.0/legacy.html

You can contact us on the Perceval forum