Better sampling; OutProbs()

Multi-shot measurement in QEngine was previously handled in a way that was technically not thread-safe for C++. This has been fixed, and QEngine sampling has been parallelized further.

The OutProbs() method has been added to the shared library extern C API, which returns the L2 norm of each OutKet() amplitude in same order.

Full Changelog: vm6502q.v9.9.62...vm6502q.v9.10.0

sha1sum results:
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f4fb8a9365a50d8a45ce74ea4587a14f443d70df libqrack-macosx_15_0_arm64.zip
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ca026cd4465a1dfd0c50a3d6df2bd961d993df2e libqrack-manylinux_2_39_x86_64.zip
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Debug QBDD high rounding

If QRACK_QBDT_SEPARABILITY_THRESHOLD were set too high, it would previously lead to segmentation faults. This release should allow the rounding parameter to be set almost arbitrarily high.

Full Changelog: vm6502q.v9.9.58...vm6502q.v9.9.62

sha1sum results:
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05f5b863349557ec517eb0692a30da67caae9e54 libqrack-win-amd64.zip

Debug QBDD sampling

This release fixes doubling-up of QBDD measurement sampling.

Full Changelog: vm6502q.v9.9.54...vm6502q.v9.9.58

sha1sum results:
48e945330d390dfe13e6d9669ddcb415d96b098c libqrack-macosx_14_0_arm64.zip
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QBDD optimization

A number of improvements have been made in QBDD simulation:

• PushStateVector() has more consistent flooring logic for very small contributions to overall state vector probability.
• Because QBDD gains little advantage from internal parallelism in most cases, internal parallelism in QBDD now defaults to OFF.
• If QBDD internal parallelism is off, then QTensorNetwork automatically parallelizes QBDD measurement sampling over shots

Full Changelog: vm6502q.v9.9.50...vm6502q.v9.9.54

sha1sum results:
10bea70febb145a1cd4adab85503d850ae40a116 libqrack-macosx_14_0_arm64.zip
0cd78e6a21e4ba5d071f74b543b596ed3d149b12 libqrack-manylinux2014_x86_64.zip
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8ee9c3597d4428b48d5d21ad85fd6724fee8897a libqrack-win-amd64.zip

Edge case segfault with 0 OpenCL/CUDA devices

This release fixes an edge case that leads to a segmentation fault, when QTensorNetwork is used in the presence of 0 available OpenCL/CUDA devices.

Full Changelog: vm6502q.v9.9.42...vm6502qv9.9.46

sha1sum results:
735297a892fb18177266d0133b904d3a522ba437 libqrack-macosx_14_0_arm64.zip
06c5149dbc4016b82a46cf2d9cfe6a40e30963a1 libqrack-manylinux2014_x86_64.zip
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576d4f1b86eb7fe7c126580987409e6fedcb0c16 libqrack-win-amd64.zip

0-GPU edge case; env. vars.; precision

This release fixes the following:

• an edge case that leads to a segmentation fault when QStabilizerHybrid is used in the presence of 0 available OpenCL/CUDA devices,
• potentially inconsistent defaults for qubit-limit and rounding-parameter environment variables,
• and rounding neighborhood for separability checks,if we check a two-state qubit for eigenstate norm equality: "machine epsilon" in C++ is the difference between 1.0 and the next greater representable number; half this value is the difference between 1.0 and the next lower representable number; half this value is used for (L2-norm) rounding neighborhood for equality with 1.0 or 0.0 in two-state Hilbert spaces (which are bounded to that range and must normalize to 1.0).

Full Changelog: vm6502qv9.9.46...vm6502q.v9.9.50

sha1sum results:
637662ad75c87b0f7421a59b7d9ed243dc8b070d libqrack-macosx_14_0_arm64.zip
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QBDD deadlock fix (and style)

A potential deadlock in QBDD Kronecker products has been fixed. Beyond that, several (non-breaking) function prototype changes have been made in accordance with standards for style.

Full Changelog: vm6502q.v9.9.37...vm6502q.v9.9.42

sha1sum results:
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QBDD and stabilizer optimization

QBDD and stabilizer methods have been optimized. An incorrect initialization of a default QEngine property was also fixed in the default constructor (though the incorrect initialization likely had no consequence). Thanks to @eltociear, for fixing a documentation typo.

What's Changed

• docs: update README.md by @eltociear in #1016
• QBDD and stabilizer commits by @WrathfulSpatula

New Contributors

• @eltociear made their first contribution in #1016

Full Changelog: vm6502q.v9.9.33...vm6502q.v9.9.37

sha1sum results:
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aea03051ff888f9c7ef5f553f89b91e971113e25 libqrack-win-amd64.zip

QBdt and BigInteger debugging and performance

QBdt and BigInteger (alias bitCapInt) have been debugged. Additionally, one should see drastically improved performance with QBdt (despite significantly reduced parallelism utilization). Systemically, on GNU/Linux, the bitCapInt type now uses 128-bit "words" rather than 64-bit words, which should lead to some performance improvement.

Note that previous releases were almost universally built with capacity for 4095 qubits in a single simulator instance; in practicality, little besides stabilizer simulation can take advantage of the vast majority of this addressing capacity. This release limits to 127 qubits in a single simulator instance, but this is a "feasible" width for Qrack approximation techniques, and performance benefits from the change.

Full Changelog: vm6502q.v9.9.28...vm6502q.v9.9.33

sha1sum results:
9ba920d97dad5f875eddcd6173b24fd1fcda0753 libqrack-macosx_14_0_arm64.zip
6998bd6e194453e572c72b79b523205d3c9869fa libqrack-manylinux2014_x86_64.zip
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cb62ec1a7ad04aa2872651043e1982e52c46a2d1 libqrack-manylinux_2_39_x86_64.zip
8253231acf756d7a129cdb1a751bc76881a61238 libqrack-win-amd64.zip

Stable maintenance release (debugging and style)

The past couple of months have seen almost exclusively style and debugging changes in Qrack. (We experimented with fixed-point math for certain applications, but it was only suitable on GNU/Linux, and the experiments mostly proved we are better leaving out fixed-point for now.) This release compared the current head of main branch to the state of Qrack about 2 months ago and whittled down the diff to a small and trustworthy set of bug fixes and adjustments according to style guide.

This release might constitute a relatively "complete" state of the core Qrack project, for a significant amount of time into the future. (Most future development is likely to focus on building out support for other quantum software frameworks.)

Happy Qracking! You rock!

Full Changelog: vm6502q.v9.9.23...vm6502q.v9.9.28

sha1sum results:
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