Error correction methods for creating Bicycle and Unicycle codes + belief decoder code evaluation

.buildkite/pipeline.yml

@@ -0,0 +1,22 @@
+env:
+  CODECOV_TOKEN: adb3f22a-231a-4f7b-8ed4-7c6c56453cbe
+  JULIA_NUM_THREADS: auto
+
+steps:
+  - label: "CI Buildkite"
+    plugins:
+      - JuliaCI/julia#v1:
+          version: "1"
+      - QuantumSavory/julia-xvfb#v1:
+      - JuliaCI/julia-test#v1: ~
+      - JuliaCI/julia-coverage#v1:
+          codecov: true
+    command: |
+      julia -e '
+        using Pkg
+        Pkg.add("QuantumSavory")
+        Pkg.build("QuantumSavory")
+        Pkg.test("QuantumSavory")
+        Pkg.add("BPGates")
+        Pkg.build("BPGates")
+        Pkg.test("BPGates")'

.github/workflows/benchmark-comment.yml

@@ -25,7 +25,7 @@ jobs:
       - uses: actions/checkout@v4
 
       # restore records from the artifacts
-      - uses: dawidd6/action-download-artifact@v2
+      - uses: dawidd6/action-download-artifact@v3
         with:
           workflow: benchmark.yml
           name: performance-tracking

.github/workflows/benchmark.yml

@@ -48,7 +48,7 @@ jobs:
         run: echo ${{ github.event.pull_request.number }} > ./pull-request-number.artifact
 
       # save as artifacts (performance tracking (comment) workflow will use it)
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: performance-tracking
           path: ./*.artifact

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.9'
+          - '1'
         os:
           - ubuntu-latest
         threads:

.github/workflows/downgrade.yml

@@ -0,0 +1,26 @@
+name: Downgrade
+on:
+  pull_request:
+    branches: [master, main]
+    paths-ignore:
+      - 'docs/**'
+  push:
+    branches: [master, main]
+    paths-ignore:
+      - 'docs/**'
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        version: ['1.9']
+    steps:
+      - uses: actions/checkout@v4
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: ${{ matrix.version }}
+      - uses: cjdoris/julia-downgrade-compat-action@v1
+        with:
+          skip: Pkg,TOML,InteractiveUtils,Random,LinearAlgebra
+      - uses: julia-actions/julia-buildpkg@v1
+      - uses: julia-actions/julia-runtest@v1

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "julia.environmentPath": "c:\\Users\\benku\\Desktop\\College Documents\\Krastanov Independent Study\\QuantumClifford.jl-CSS_Builder"
+}

CHANGELOG.md

@@ -6,7 +6,16 @@
 
 # News
 
-## v0.8.17 - 2023-10-16
+## v0.8.19 - 2023-12-16
+
+- Bumping up the lower bounds of many dependencies and adding lower-bound compatibility checks to CI.
+
+## v0.8.18 - 2023-11-22
+
+- `ECC.faults_matrix` detects and warns when encountery codes with redundant checks.
+
+## v0.8.17 - 2023-10-17
+
 - **(fix)** Some `affectedqubits` methods were returning single integers instead of a one-tuple.
 - The non-public `ECC` module has seen a few improvements (a `naive_encoding_circuit` implementation and a few new codes), as well as some breaking changes to API.
 

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2023 Abhishek Bhatt
+Copyright (c) 2023 Stefan Krastanov
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

Project.toml

@@ -1,7 +1,7 @@
 name = "QuantumClifford"
 uuid = "0525e862-1e90-11e9-3e4d-1b39d7109de1"
 authors = ["Stefan Krastanov <[email protected]>"]
-version = "0.8.18"
+version = "0.8.19"
 
 [deps]
 Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
@@ -18,6 +18,8 @@ PrecompileTools = "aea7be01-6a6a-4083-8856-8a6e6704d82a"
 QuantumInterface = "5717a53b-5d69-4fa3-b976-0bf2f97ca1e5"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 SIMD = "fdea26ae-647d-5447-a871-4b548cad5224"
+SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
+Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 SumTypes = "8e1ec7a9-0e02-4297-b0fe-6433085c89f2"
 
 [weakdeps]
@@ -38,18 +40,21 @@ QuantumCliffordQuantikzExt = "Quantikz"
 CUDA = "4.4.0"
 Combinatorics = "1.0"
 DataStructures = "0.18"
-DocStringExtensions = "0.8, 0.9"
-Graphs = "1.4.1"
+DocStringExtensions = "0.9"
+Graphs = "1.9"
 HostCPUFeatures = "0.1.6"
 ILog2 = "0.2.3"
+InteractiveUtils = "1"
+LinearAlgebra = "1"
 MacroTools = "0.5.9"
 Makie = "0.19.7"
-Nemo = "0.34, 0.35, 0.36"
+Nemo = "0.38"
 Plots = "1.38.0"
-PrecompileTools = "1"
+PrecompileTools = "1.2"
 Quantikz = "1.3.1"
-QuantumInterface = "0.3.0"
-QuantumOpticsBase = "0.4"
+QuantumInterface = "0.3.3"
+QuantumOpticsBase = "0.4.18"
+Random = "1"
 SIMD = "3.4.0"
-SumTypes = "0.4.4, 0.5"
+SumTypes = "0.5"
 julia = "1.9"

README.md

@@ -11,7 +11,8 @@
     <tr>
         <td>Continuous integration</td>
         <td>
-            <a href="https://github.com/QuantumSavory/QuantumClifford.jl/actions?query=workflow%3ACI+branch%3Amaster"><img src="https://img.shields.io/github/actions/workflow/status/QuantumSavory/QuantumClifford.jl/ci.yml?branch=master" alt="GitHub Workflow Status"></a>
+            <a href="https://github.com/QuantumSavory/QuantumClifford.jl/actions?query=workflow%3ACI+branch%3Amaster"><img src="https://github.com/QuantumSavory/QuantumClifford.jl/actions/workflows/ci.yml/badge.svg" alt="GitHub Workflow Status"></a>
+            <a href="https://buildkite.com/quantumsavory/quantumclifford"><img src="https://badge.buildkite.com/8ef137151415f29c03544c5b7963f6bc6afc1022f29cfc072a.svg" alt="Buildkite Workflow Status"></a>
         </td>
     </tr><tr></tr>
     <tr>

src/ecc/ECC.jl

@@ -1,18 +1,22 @@
 module ECC
 
 using LinearAlgebra
-using QuantumClifford
-using QuantumClifford: AbstractOperation, AbstractStabilizer
+using QuantumClifford, SparseArrays
+using QuantumClifford: AbstractOperation, AbstractStabilizer, Stabilizer
 import QuantumClifford: Stabilizer, MixedDestabilizer
 using DocStringExtensions
 using Combinatorics: combinations
+using Statistics: std
+using Nemo: ZZ, residue_ring, matrix
 
 abstract type AbstractECC end
 
 export Shor9, Steane7, Cleve8, Perfect5, Bitflip3,
     parity_checks, naive_syndrome_circuit, shor_syndrome_circuit, naive_encoding_circuit,
     code_n, code_s, code_k, rate, distance,
-    isdegenerate, faults_matrix
+    isdegenerate, faults_matrix,
+    Unicycle, Bicycle,
+    CSS
 
 """Parity check tableau of a code."""
 function parity_checks end
@@ -234,10 +238,12 @@ We just gather all our syndrome measurement **and logical observables** from the
 and then use them with the fault matrix in the syndrome decoding simulation.
 """
 function faults_matrix(c::Stabilizer)
+    md = MixedDestabilizer(c)
     s, n = size(c)
-    k = n-s
+    r = rank(md)
+    k = n - r
+    k == n-s || @warn "`faults_matrix` was called on an ECC that has redundant rows (is rank-deficient). `faults_matrix` corrected for that, however this is a frequent source of mistakes and inefficiencies. We advise you remove redundant rows from your ECC."
     O = falses(2k, 2n)
-    md = MixedDestabilizer(c)
     logviews = [logicalxview(md); logicalzview(md)]
     errors = [one(Stabilizer,n; basis=:X);one(Stabilizer,n)]
     for i in 1:2k
@@ -296,4 +302,7 @@ include("codes/steanecode.jl")
 include("codes/shorcode.jl")
 include("codes/clevecode.jl")
 
+include("codes/css.jl")
+include("codes/simple_sparse_codes.jl")
+
 end #module

src/ecc/codes/css.jl

@@ -0,0 +1,37 @@
+"""An arbitrary CSS error correcting code defined by its X and Z checks."""
+struct CSS <: AbstractECC
+    Hx
+    Hz
+    """Creates a CSS code using the two provided matrices where Hx contains the X checks and Hz contains the Z checks."""
+    function CSS(Hx, Hz)
+        n = size(Hx, 2)
+        if n != size(Hz, 2) error("When constructing a CSS quantum code, the two classical codes are required to have the same block size") end
+        if size(Hx,1)+size(Hz,1) >= n error("When constructing a CSS quantum code, the total number of checks (rows) in the parity checks of the two classical codes have to be lower than the block size (the number of columns).") end
+        return new(Hx, Hz)
+    end
+end
+
+function boolean_tableau(c::CSS)
+    Hx_height, Hx_width = size(c.Hx)
+    Hz_height, Hz_width = size(x.Hz)
+    checks_matrix = falses(Hx_height + Hz_height, Hx_width + Hz_width)
+    checks_matrix[1:Hx_height, 1:Hx_width] = c.Hx
+    checks_matrix[Hx_height+1:end, Hx_width+1:end] = c.Hz
+    return CSS(checks_matrix)
+end
+
+"""Returns the stabilizer making up the parity check tableau."""
+function parity_checks(c::CSS)
+    extended_Hx = Matrix{Bool}(vcat(c.Hx, zeros(size(c.Hz))))
+    extended_Hz = Matrix{Bool}(vcat(zeros(size(c.Hx)), c.Hz))
+    Stabilizer(fill(0x0, size(c.Hx, 2) + size(c.Hz, 2)), extended_Hx, extended_Hz)
+end
+
+"""Returns the block length of the code."""
+code_n(c::CSS) = size(c.Hx,2)
+
+"""Returns the depth of the parity check matrix"""
+code_m(c::CSS) = size(c.Hx, 1) + size(c.Hz, 1)
+
+"""Returns the number of encoded qubits"""
+code_k(c::CSS) = (2 * size(c.Hx,2)) - code_m(c)