Qualtran v0.6

We're proud to announce the latest minor release of Qualtran. This release brings infrastructure improvements for writing controlled bloqs, lays the groundwork for more interoperability with other tools, and contains major additions and improvements to our library of bloqs.

Easier and optimized controlled bloqs

ControlledViaAnd was included in the previous release of Qualtran. For multi-qubit control specs, it will compute the conditional once and use single-bit controls in subbloqs. The older Controlled metabloq uses a "total control" decomposition where each subbloq is controlled according to the requested control spec (no matter how complicated it is).

In this release, the default Bloq.get_ctrl_system will use a ladder of And to reduce multiple controls to a single control bit for complex control specs. This is a more optimized default. Bloq authors will always be free to override Bloq.get_ctrl_system for complete flexibility. With this change, more cases can be adequately handled by the automatic default.

This overhaul was contributed by @anurudhp in #1373 #1456 #1451 #1481 #1490, and #1491.

Backwards-incompatible changes

We always strive to avoid any breaking changes in expressing or analyzing quantum algorithms using the public classes, methods, and functions in the qualtran namespace (outside of qualtran.bloqs). However, prior to a 1.0 release, we may make breaking changes that would otherwise accumulate too much tech debt. This release contains some minor incompatible changes, detailed (with alternatives) below.

Note that the qualtran.bloqs library of subroutines will be under active development for the foreseeable future, and we will make incompatible changes to the quantum algorithms for correctness and accuracy following quantum algorithms research results.

• Bloq.pretty_name has been removed as a base-class method. Override __str__ and use str() to get a string representation of a bloq, by @dstrain115 in #1402
• The deprecated qualtran.drawing.GraphvizCounts class has been removed. Convenience drawing methods had already been switched to use the replacement, GraphvizCallGraph, by @dstrain115 in #1410
• The deprecated Bloq._t_complexity_ override has been removed as a base-class method. Override Bloq.my_static_costs instead. The QECGatesCost estimator will still respect _t_complexity_ methods on derived classes if set to legacy=True mode, by @mpharrigan in #1377
• Controlled meta-bloqs can only be used to control bloqs with all thru-registers. The meaning of a controlled allocation is ill-defined, by @mpharrigan in #1305
• The default fallback for Bloq.get_ctrl_system will use ControlledViaAnd, see the above section in these release notes.
• And is now an atomic, leaf bloq. The circuit decomposition in terms of T and measurement-based uncomputation is still available via And.to_clifford_t_circuit(), by @anurudhp in #1513

Interoperability and devops

This release includes dependency adjustments to support interoperability with other quantum tools. This release adds a new dependency PennyLane, but full interoperability requires pennylane>=0.41, which is not yet released at the time of writing. A runtime check is performed, so if you manually update your environment with pennylane>=0.41, the full functionality will be enabled. This logic was included in Qualtran v0.6.1. The prior tag v0.6.0 depended on a pre-release that is not available from PyPI, so qualtran==0.6.0 is not available on PyPI.

• [Bartiq] upgraded to version 0.6.0 by @mstechly in #1409
• [Cirq] dependency is no longer pinned to a particular version by @mpharrigan in #1460
• [Cirq, bugfix] Allow computing cost from decomposition of Cirq gates by @anurudhp in #1510
• [QREF] Add option to generate QREF from callgraphs by @mstechly in #1522
• [PennyLane] Qualtran bloqs to PennyLane by @austingmhuang in #1559
• [PyZX] Dependency added for future interoperability, by @anurudhp in #1562

Additionally, our repository has been spruced up with a new README, citation information, and dev tools by @mhucka in #1568 #1569 #1571 #1573 #1572 #1597 #1575 #1580, #1598, and #1601

Bloq library additions

Our library of quantum subroutines continues to grow, with substantial additions for doing arithmetic in various fields.

• create DirtyOutOfPlaceMontgomeryModMul by @NoureldinYosri in #1395
• Add Equals() bloq by @fpapa250 in #1411
• Add QGF data type for Galois Fields by @tanujkhattar in #1433
• Add GF2Multiplication bloq for multiplication over GF($2^m$) by @tanujkhattar in #1436
• Add GF2Add bloq for addition over GF($2^m$) by @tanujkhattar in #1438
• Add GF2Square bloq for squaring over GF($2^m$) by @tanujkhattar in #1441
• Add GF2Inverse bloq for computing inverse over GF($2^m$) by @tanujkhattar in #1442
• Add GF2AddK for in place addition of a constant over GF($2^m$) by @tanujkhattar in #1447
• PlusEqualProduct version of GFMultiplication for GF($2^m$) by @tanujkhattar in #1457
• Optimized implementation of GF2Inverse by @tanujkhattar in #1459
• Implement CtrlScaleModAdd and CModAddK bloqs for Modular Exponentiation by @fpapa250 in #1432
• Add RSA Phase Estimate Bloq and Move ModExp to rsa/ subdirectory by @fpapa250 in #1428
• Create linear half comparison bloqs by @NoureldinYosri in #1408
• Add ECAdd() Bloq by @fpapa250 in #1425
• Create KaliskiModInverse by @NoureldinYosri in #1464
• Add SparseMatrixHermitian block-encoding by @anurudhp in #1479
• Add Decomposition of ECWindowAddR by @fpapa250 in #1477
• Deprecate MultiControlPauli by @anurudhp in #1492
• Add list primitives from Quartic speedups paper by @anurudhp in #1503
• Implement Kikuchi guiding state preparation by @anurudhp in #1504
• Add bloq for constant polynomial multiplication modulo in GF(2) by @NoureldinYosri in #1516
• Add bloq for Binary Polynomial Multiplication by @NoureldinYosri in #1554
• Single-qubit and Controlled Z rotations by @mpharrigan in #1455

Bloq library enhancements

The existing library has been enhanced with more accurate resource estimation, bug fixes, and bespoke controlled versions of more bloqs.

• Add my_static_costs override for accurate QubitCounts for qrom bloqs by @tanujkhattar in #1414
• Add serialization for ECPoint arg type. by @fpapa250 in #1412
• Make intermediate additions unsigned in ModAdd by @fpapa250 in #1424
• Add classical action test for ModAdd by @NoureldinYosri in #1427
• fix call graph for Equals by @anurudhp in #1429
• sparse state prep: allow user to pick target bitsize if needed by @anurudhp in #1430
• Update THC Prepare to use QROAMClean by @fdmalone in #1378
• Bugfix in Partition to support QGF type registers by @tanujkhattar in #1448
• Override KaliskiModInverse.adjoint by @NoureldinYosri in #1483
• Modify KaliskiModInverse to support zero by @NoureldinYosri in #1486
• Replace ModInv shim with KaliskiModInverse in ECAdd bloq by @fpapa250 in #1485
• Upgrade AddK - use dtype and simplify controls by @anurudhp in #1493
• Fix bug in KaliskiStep3 and add tests for all steps by @NoureldinYosri in #1496
• Fix symbolic call graphs for factoring phase estimates by @fpapa250 ...

Qualtran v0.5

This preview release of Qualtran contains many improvements and new bloqs.

This is the last planned release before the 1.0 release of Qualtran. 1.0 will bring stronger stability guarantees to the core Qualtran framework: namely everything in the qualtran namespace outside of qualtran.bloqs. The library of bloqs will continue to be extended and edited for greater breadth and accuracy. This development release contains some backwards-incompatible changes to prepare for 1.0. Read on for more information

Bartiq and QREF integration

This release includes interoperability with Bartiq via the QREF format implemented by @mstechly in #1194. Interoperability between quantum algorithms tooling is crucial to accelerate progress in the field.

Qualtran software paper

We've authored a manuscript describing the design of Qualtran, some important algorithmic primitives contained in qualtran.bloqs, and case studies on problems of interest. If you use Qualtran in your own work, please cite:

Expressing and Analyzing Quantum Algorithms with Qualtran. arXiv:2409.04643.

Gate counting and leaf bloqs

We've unified the gate counting framework under the qualtran.resource_counting framework.

• The _t_complexity_ annotation is deprecated. Please continue to annotate callees with build_call_graph or use my_static_costs to provide a static override.
• The cirq_interop.t_complexity function no longer uses any custom logic. Rather, it goes via qualtran.resource.estimation tools; specifically the QECGatesCost cost key. There should be no observable change to the computed costs. #1313 #1359 #1323 #1333
• Toffoli is now an atomic, leaf bloq #1388
• CSwap is now an atomic leaf bloq #1393
• And will become an atomic leaf bloq #1347
• The GraphvizCallGraph.from_bloq helper method can draw call graphs with costs #1254

Tensor simulation overhaul

The tensor simulation protocol was changed to support efficient simulation of a larger class of circuits, including shallow-but-wide circuits. Qualtran can simulate a 2x32-qubit adder using only 6 qubit's worth of RAM for a specific input/output ket following the changes.

• Overhaul implemented in #1070. Tensor simulation will always try to flatten as much as possible before starting the contraction. The semantics of my_tensors have changed. If you are overriding this method to support tensor simulation, consider relying directly on the decomposition or read the documentation for full details on how to implement the new method.
• Changes to .flatten in #1061. Flattening will no longer raise an error if a bloq doesn't have a decomposition. .flatten() with no arguments will flatten as much as possible.

Physical cost models

The qualtran.surface_code module has been refactored so both Beverland- and Gidney-derived models follow the same interface.

• Code changes in #1141 #1154 #1157 #1183 #1185
• qualtran.resource_estimation.GateCounts is used directly. AlgorithmSummary and MagicCount dataclasses have been removed as redundant.

Other framework changes

• The bit_tools module has been removed and replaced with QDType features by @charlesyuan314 in #1041. Please migrate your code to use QDType methods to convert between bits. New, vectorized from_bits and to_bits by @anurudhp in #1199
• Greedy topological sort of the binst graph to minimize qubit allocations / deallocations by @tanujkhattar in #1099
• Cirq interop overhaul/bugfixes @tanujkhattar in #1100
• QFxp: use integer values for classical sim instead of fxpmath.Fxp by @anurudhp in #1204
• Change return type of build_call_graph to set | dict by @dstrain115 in #1356 #1392
• pretty_name is deprecated #1340. Use __str__.
• Bloq.supports_decompose_bloq has been removed in #1382. Use try/except.
• BoundedQUInt has been renamed to BQUInt by @fdmalone in #1363
• Better support for symbolics in Signature by @anurudhp in #1353 and @mpharrigan in #1301
• param ctrl_spec of get_ctrl_system will always be non-None by @anurudhp in #1209
• Zero-bitsize connections are explicitly not allowed by @mpharrigan in #1105

New and updated bloqs

• Implement decomposition for BitonicSort by @anurudhp in #1089
• Add AutoPartition and BloqBuilder.add_and_partition to fit bloqs together whose registers don't quite match by @charlesyuan314 in #1086
• Implement classical action of Cast bloq by @NoureldinYosri in #1093
• Add Unitary and TensorProduct block encodings by @charlesyuan314 in #1094
• GlobalPhase: use exponent, and implement controlled (ZPowGate) by @anurudhp in #1117
• Create ApplyLthBloq as a simple SELECT oracle by @charlesyuan314 in #1107
• Add Product block encoding by @charlesyuan314 in #1106
• Add Phase block encoding by @charlesyuan314 in #1129
• Add LinearCombination block encoding by @charlesyuan314 in #1133
• Permutation Bloq by @anurudhp in #1110
• Sparse state preparation via alias sampling by @anurudhp in #1067
• Implement Negate (two's complement) by @anurudhp in #1144
• Add Xor bloq by @charlesyuan314 in #1149
• Add InvertRealNumber bloq by @charlesyuan314 in #1151
• Add BitwiseNot by @anurudhp in #1161
• Add SubtractFrom to subtract from a register in place by @charlesyuan314 in #1158
• Switch SubtractFrom to use BitwiseNot by @charlesyuan314 in #1164
• Create SparseMatrix block encoding by @charlesyuan314 in #1143
• Optimize gate count of Subtract to n-1 Toffolis by @NoureldinYosri in #1057
• CHadamard by @mpharrigan in #1114
• CYGate by @mpharrigan in #1115
• CZ by @mpharrigan in #1116
• Disallow zero sized registers in QROMs and PRGAViaPhaseGradient by @tanujkhattar in #1160
• Add ExplicitEntryOracle to block encode a matrix by @charlesyuan314 in #1166
• ControlledAddOrSubtract Bloq by @anurudhp in #1145
• Update classical action of addition gates and fix classical action bug in Join by @NoureldinYosri in #1174
• Implement generic MultiControlledBloq using single-controlled subbloq + And ladder. by @anurudhp in #1155
• ControlledViaAnd tests and bloq examples by @anurudhp in #1182
• Add SignExtend for two's complement sign extension by @anurudhp in #1162
• Add SymmetricBanded matrix block encoding by @charlesyuan314 in #1177
• Add ArcSin bloq by @charlesyuan314 in #1188
• Add symbolic call graph for SparseMatrix by @charlesyuan314 in #1193
• Revamp ChebyshevPolynomial by @charlesyuan314 in #1213
• Bitwise bloqs are self adjoint by @anurudhp in #1220
• Update QROAM in chemistry prepare bloqs to use clean ancilla by @fdmalone in #1226
• Add ScaledChebyshevPolynomial bloq by @charlesyuan314 in #1231
• Add an optimizer for LinearCombinations by @charlesyuan314 in #1232
• Add FFT QSP by @Epsilon1024 in #1078
• RzViaPhaseG...

Qualtran v0.4

We're pleased to announce the latest beta release of Qualtran: v0.4.0. This release includes many improvements and fixes throughout the library, but some highlights include:

Highlights

• Support for arbitrary CostKeys: compute gate counts, qubit counts, or define your own cost
• Many more bloqs support symbolic parameters and cost estimates
• Bugfixes for using Qualtran on Windows
• Better control for how bloqs display themselves in diagrams
• Mypy type-checking is enabled and enforced library-wide.

Full Changelog: v0.3.0...v0.4.0

Qualtran v0.3.0

This is an incremental beta release of Qualtran.

Highlights

• Quantum data types. Registers now have types.
• T-complexity protocol improvements.
• More bloqs!

Full Changelog: v0.2.0...v0.3.0

Qualtran v0.2.0

This is an incremental beta release of Qualtran.

Highlights include:

• Improved Cirq interoperability, and the absorption of the-package-formerly-known-as Cirq-FT into the Qualtran repository.
• More chemistry bloqs.
• The Adjoint protocol

Full Changelog: v0.1.0...v0.2.0

Qualtran v0.1.0

This is the initial, experimental preview release of Qualtran