adding iscss for issue #222

CHANGELOG.md

@@ -7,7 +7,7 @@
 # News
 
 ## v0.8.21 - 2024-03-17
-
+- adding iscss function
 - Implemented the Gottesman code family, also known as [[2^j, 2^j - j - 2, 3]] quantum Hamming codes.
 - Bump the `PyQDecoders` dependency, switching to `PythonCall` behind the scenes for reliability.
 - Bump the `LDPCDecoders` dependency.

src/ecc/ECC.jl

@@ -12,7 +12,7 @@
 
 abstract type AbstractECC end
 
-export parity_checks, parity_checks_x, parity_checks_z,
+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,
@@ -49,6 +49,11 @@
     throw(lazy"Codes of type $(typeof(code)) do not have separate X and Z parity checks, either because they are not a CSS code and thus inherently do not have separate checks, or because its separate checks are not yet implemented in this library.")
 end
 
+# default CSS method
+function iscss(::Type{T}) where T<:AbstractECC
+    return true
+end
+
 parity_checks(s::Stabilizer) = s
 Stabilizer(c::AbstractECC) = parity_checks(c)
 MixedDestabilizer(c::AbstractECC; kwarg...) = MixedDestabilizer(Stabilizer(c); kwarg...)

src/ecc/codes/gottesman.jl

@@ -12,6 +12,10 @@
     end
 end
 
+function iscss(::Type{Gottesman})
+    return false
+end
+
 code_n(c::Gottesman) = 2^c.j
 
 function parity_checks(c::Gottesman)

src/ecc/codes/steanecode.jl

@@ -2,6 +2,10 @@
 
 struct Steane7 <: AbstractECC end
 
+function iscss(::Type{Steane7})
+    return true
+end
+
 parity_checks(c::Steane7) = S"___XXXX
                               _XX__XX
                               X_X_X_X

src/ecc/codes/toric.jl

@@ -4,6 +4,10 @@ struct Toric <: AbstractECC
     dz::Int
 end
 
+function iscss(::Type{Toric})
+    return true
+end
+
 code_n(c::Toric) = 2*c.dx*c.dz
 
 function parity_checks_xz(c::Toric)