simplify circshift (it exists in Base) and do not export (we do not e…

…xport the vast majority of classical codes as that would be a too heavy of a commitment to forward stability of features that are not heavily used yet)

docs/src/references.bib

@@ -419,13 +419,13 @@ @article{RevModPhys.87.307
 }
 
 @misc{goodenough2024bipartiteentanglementnoisystabilizer,
-  title={Bipartite entanglement of noisy stabilizer states through the lens of stabilizer codes}, 
+  title={Bipartite entanglement of noisy stabilizer states through the lens of stabilizer codes},
   author={Kenneth Goodenough and Aqil Sajjad and Eneet Kaur and Saikat Guha and Don Towsley},
   year={2024},
   eprint={2406.02427},
   archivePrefix={arXiv},
   primaryClass={quant-ph},
-  url={https://arxiv.org/abs/2406.02427}, 
+  url={https://arxiv.org/abs/2406.02427},
 }
 
 @article{panteleev2021degenerate,
@@ -532,7 +532,7 @@ @article{wang2024coprime
 }
 
 @misc{voss2024multivariatebicyclecodes,
-  title={Multivariate Bicycle Codes}, 
+  title={Multivariate Bicycle Codes},
   author={Lukas Voss and Sim Jian Xian and Tobias Haug and Kishor Bharti},
   year={2024},
   eprint={2406.19151},

src/ecc/ECC.jl

@@ -24,7 +24,7 @@ export parity_checks, parity_checks_x, parity_checks_z, iscss,
     code_n, code_s, code_k, rate, distance,
     isdegenerate, faults_matrix,
     naive_syndrome_circuit, shor_syndrome_circuit, naive_encoding_circuit,
-    RepCode, LiftedCode, Golay,
+    RepCode, LiftedCode,
     CSS,
     Shor9, Steane7, Cleve8, Perfect5, Bitflip3,
     Toric, Gottesman, Surface, Concat, CircuitCode, QuantumReedMuller,

src/ecc/codes/classical/golay.jl

@@ -21,8 +21,8 @@ the original parity check matrix `H₂₄`. Thus, all punctured codes are equiva
 The ECC Zoo has an [entry for this family](https://errorcorrectionzoo.org/c/golay).
 """
 struct Golay <: ClassicalCode
-    n::Int 
-   
+    n::Int
+
     function Golay(n)
         if !(n in (23, 24))
             throw(ArgumentError("Invalid parameters: `n` must be either 24 or 23 to obtain a valid code."))
@@ -31,11 +31,6 @@ struct Golay <: ClassicalCode
     end
 end
 
-function _circshift_row_golay(row::Vector{Int}, shift::Int, n::Int)
-    l = length(row)
-    return [row[mod((i - shift - 1), l) + 1] for i in 1:l]
-end
-
 # bordered reverse circulant matrix (see section 1.9.1, pg. 30-33) of [huffman2010fundamentals](@cite).
 function _create_A₂₄_golay(n::Int)
     A = zeros(Int, n ÷ 2, n ÷ 2)
@@ -48,19 +43,19 @@ function _create_A₂₄_golay(n::Int)
     end
     # Fill in the rest of the rows using the reverse circulant property.
     for i in 3:n ÷ 2
-        A[i, 2:end] = _circshift_row_golay(A[i - 1, 2:end], -1, n ÷ 2)
-        A[i, 1] = 1 
+        A[i, 2:end] = circshift(A[i - 1, 2:end], -1)
+        A[i, 1] = 1
     end
     return A
 end
 
 function generator(g::Golay)
-    if g.n == 24 
+    if g.n == 24
         A₂₄ = _create_A₂₄_golay(24)
         I₁₂ = LinearAlgebra.Diagonal(ones(Int, g.n ÷ 2))
         G₂₄ = hcat(I₁₂, (A₂₄)')
         return G₂₄
-    else 
+    else
         A₂₄ = _create_A₂₄_golay(24)
         A₂₃ = A₂₄[:, 1:end - 1]
         I₁₂ = LinearAlgebra.Diagonal(ones(Int, g.n ÷ 2))
@@ -75,7 +70,7 @@ function parity_checks(g::Golay)
         I₁₂ = LinearAlgebra.Diagonal(ones(Int, g.n ÷ 2))
         H₂₄ = hcat((A₂₄)', I₁₂)
         return H₂₄
-    else 
+    else
         A₂₄ = _create_A₂₄_golay(24)
         A₂₃ = A₂₄[:, 1:end - 1]
         I₁₂ = LinearAlgebra.Diagonal(ones(Int, g.n ÷ 2))