ECC decoder pipeline

.gitignore

@@ -3,4 +3,5 @@ Manifest.toml
 LocalPreferences.toml
 */.*swp
 scratch/
-*.cov
+*.cov
+.vscode

Project.toml

@@ -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]
@@ -53,3 +55,4 @@ QuantumOpticsBase = "0.4"
 SIMD = "3.4.0"
 SumTypes = "0.4.4, 0.5"
 julia = "1.9"
+Statistics = "1.9.0"

docs/make.jl

@@ -20,7 +20,7 @@ doctest = false,
 clean = true,
 sitename = "QuantumClifford.jl",
 format = Documenter.HTML(size_threshold_ignore = ["API.md"]),
-modules = [QuantumClifford, QuantumClifford.Experimental.NoisyCircuits, QuantumInterface],
+modules = [QuantumClifford, QuantumClifford.Experimental.NoisyCircuits, QuantumClifford.ECC, QuantumInterface],
 warnonly = [:missing_docs],
 authors = "Stefan Krastanov",
 pages = [
@@ -41,6 +41,9 @@ pages = [
     "Circuit Operations" => "noisycircuits_ops.md",
     "API" => "noisycircuits_API.md"
 ],
+"ECC compendium" => [
+    "API" => "ECC_API.md"
+],
 "All Gates" => "allops.md",
 "Visualizations" => "plotting.md",
 "API" => "API.md",

docs/src/ECC_API copy.md

@@ -0,0 +1,6 @@
+# Full ECC API (autogenerated)
+
+```@autodocs
+Modules = [QuantumClifford.ECC]
+Private = false
+```

src/affectedqubits.jl

@@ -12,7 +12,9 @@ affectedqubits(p::PauliOperator) = 1:length(p)
 affectedqubits(m::Union{AbstractMeasurement,sMRX,sMRY,sMRZ}) = (m.qubit,)
 affectedqubits(v::VerifyOp) = v.indices
 affectedqubits(c::CliffordOperator) = 1:nqubits(c)
+affectedqubits(c::ClassicalXOR) = ()
 
 affectedbits(o) = ()
 affectedbits(m::sMRZ) = (m.bit,)
 affectedbits(m::sMZ) = (m.bit,)
+affectedbits(c::ClassicalXOR) = (c.bits..., c.store)

src/ecc/ECC.jl

@@ -2,17 +2,22 @@ module ECC
 
 using LinearAlgebra
 using QuantumClifford
-using QuantumClifford: AbstractOperation, AbstractStabilizer
+using QuantumClifford: AbstractOperation, AbstractStabilizer, Stabilizer
 import QuantumClifford: Stabilizer, MixedDestabilizer
 using DocStringExtensions
 using Combinatorics: combinations
+using SparseArrays
+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
+export parity_checks, code_n, code_s, code_k, rate, distance,
+    isdegenerate, faults_matrix,
+    naive_syndrome_circuit, shor_syndrome_circuit, naive_encoding_circuit,
+    CSS, Unicycle, Bicycle,
+    Shor9, Steane7, Cleve8, Perfect5, Bitflip3,
+    evaluate_decoder, TableDecoder
 
 """Parity check tableau of a code."""
 function parity_checks end
@@ -289,11 +294,14 @@ function isdegenerate(H::Stabilizer, d::Int=1)
 end
 
 include("circuits.jl")
+include("decoder_pipeline.jl")
 
+include("codes/css.jl")
 include("codes/bitflipcode.jl")
 include("codes/fivequbit.jl")
 include("codes/steanecode.jl")
 include("codes/shorcode.jl")
 include("codes/clevecode.jl")
+include("codes/simple_sparse_codes.jl")
 
 end #module

src/ecc/circuits.jl

@@ -142,7 +142,7 @@ Use the `ancillary_index` and `bit_index` arguments to offset where the correspo
 Ancillary qubits
 
 Returns:
-  - The cat state preparation circuit.
+  - The ancillary cat state preparation circuit.
   - The Shor syndrome measurement circuit.
   - The number of ancillary qubits that were added.
   - The list of bit indices that store the final measurement results.
@@ -165,7 +165,7 @@ and stores the measurement result into classical bits starting at `bit_index`.
 The final measurement result is the XOR of all the bits.
 
 Returns:
-  - The cat state preparation circuit.
+  - The ancillary cat state preparation circuit.
   - The Shor syndrome measurement circuit.
   - One more than the index of the last added ancillary qubit.
   - One more than the index of the last added classical bit.

src/ecc/codes/css.jl

@@ -0,0 +1,28 @@
+"""An arbitrary CSS error correcting code defined by its X and Z checks.
+
+```jldoctest
+julia> CSS([0 1 1 0; 1 1 0 0], [1 1 1 1]) |> parity_checks
++ _XX_
++ XX__
++ ZZZZ
+```"""
+struct CSS <: AbstractECC
+    Hx::Matrix{Bool}
+    Hz::Matrix{Bool}
+    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
+        new(Hx, Hz)
+    end
+end
+
+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, 1) + size(c.Hz, 1)), extended_Hx, extended_Hz)
+end
+
+code_n(c::CSS) = size(c.Hx,2)
+
+code_s(c::CSS) = size(c.Hx, 1) + size(c.Hz, 1)