Migrate express functionality and AbstractRepresentation type to QuantumInterface

CHANGELOG.md

@@ -1,5 +1,9 @@
 # News
 
+## v0.4.6 - 2025-01-18
+
+- Migrate `express` functionality and representation types to QuantumInterface.
+
 ## v0.4.5 - 2024-11-14
 
 - Updated compat lower bounds for Symbolics to v6 (and for SymbolicUtils and TermInterface)

Project.toml

@@ -1,7 +1,7 @@
 name = "QuantumSymbolics"
 uuid = "efa7fd63-0460-4890-beb7-be1bbdfbaeae"
 authors = ["QuantumSymbolics.jl contributors"]
-version = "0.4.5"
+version = "0.4.6"
 
 [deps]
 Latexify = "23fbe1c1-3f47-55db-b15f-69d7ec21a316"
@@ -28,7 +28,7 @@ LinearAlgebra = "1.9"
 MacroTools = "0.5.13"
 PrecompileTools = "1.2"
 QuantumClifford = "0.8.19, 0.9"
-QuantumInterface = "0.3.3"
+QuantumInterface = "0.3.7"
 QuantumOpticsBase = "0.4.22, 0.5"
 SymbolicUtils = "3.7"
 Symbolics = "6"

src/QSymbolicsBase/QSymbolicsBase.jl

@@ -16,7 +16,9 @@ import QuantumInterface:
     basis,Basis,samebases,IncompatibleBases,SpinBasis,FockBasis,CompositeBasis,
     nqubits,
     projector,dagger,tr,ptrace,
-    AbstractBra,AbstractKet,AbstractOperator,AbstractSuperOperator
+    AbstractBra,AbstractKet,AbstractOperator,AbstractSuperOperator,
+    express,AbstractRepresentation,AbstractUse,UseAsState,UseAsObservable,UseAsOperation,
+    QuantumOpticsRepr,QuantumMCRepr,CliffordRepr
 
 export SymQObj,QObj,
        AbstractRepresentation,AbstractUse,
@@ -53,13 +55,6 @@ export SymQObj,QObj,
 # Metadata cache helpers
 ##
 
-"""An abstract type for the supported representation of quantum objects."""
-abstract type AbstractRepresentation end
-abstract type AbstractUse end
-struct UseAsState <: AbstractUse end
-struct UseAsOperation <: AbstractUse end
-struct UseAsObservable <: AbstractUse end
-
 const CacheType = Dict{Tuple{<:AbstractRepresentation,<:AbstractUse},Any}
 mutable struct Metadata
     express_cache::CacheType # TODO use more efficient mapping

src/QSymbolicsBase/express.jl

@@ -11,7 +11,7 @@ import SymbolicUtils: Symbolic
 """
     express(s, repr::AbstractRepresentation=QuantumOpticsRepr()[, use::AbstractUse])
 
-The main interface for expressing quantum objects in various representations.
+The main interface for expressing symbolic quantum objects in various representations.
 
 ```jldoctest
 julia> express(X1)
@@ -37,8 +37,6 @@ julia> express(QuantumSymbolics.X, CliffordRepr(), UseAsObservable())
 + X
 ```
 """
-function express end
-
 function express(state::Symbolic, repr::AbstractRepresentation, use::AbstractUse)
     md = metadata(state)
     isnothing(md) && return express_from_cache(express_nolookup(state, repr, use))
@@ -51,10 +49,6 @@ function express(state::Symbolic, repr::AbstractRepresentation, use::AbstractUse
     end
 end
 
-express(s::Number, repr::AbstractRepresentation, use::AbstractUse) = s
-
-express(s, repr::AbstractRepresentation) = express(s, repr, UseAsState())
-
 express_nolookup(x, repr::AbstractRepresentation, ::AbstractUse) = express_nolookup(x, repr)
 
 express_nolookup(x, repr::AbstractRepresentation, ::UseAsState) = express_nolookup(x, repr)
@@ -72,28 +66,12 @@ function consistent_representation(reprs,state)
     end
     first(reprs)
 end
-
-##
-# Commonly used representations -- interfaces for each one defined in separate packages
-##
-
-"""Representation using kets, bras, density matrices, and superoperators governed by `QuantumOptics.jl`."""
-@kwdef struct QuantumOpticsRepr <: AbstractRepresentation 
-    cutoff::Int = 2
-end
-"""Similar to `QuantumOpticsRepr`, but using trajectories instead of superoperators."""
-struct QuantumMCRepr <: AbstractRepresentation end
-"""Representation using tableaux governed by `QuantumClifford.jl`"""
-struct CliffordRepr <: AbstractRepresentation end
-
-express(state::Symbolic) = express(state, QuantumOpticsRepr()) # The default representation
 express_nolookup(state, ::QuantumMCRepr) = express_nolookup(state, QuantumOpticsRepr())
-express(state) = state
 
 function express_nolookup(s, repr::AbstractRepresentation)
     if isexpr(s)
         operation(s)(express.(arguments(s), (repr,))...)
     else
         error("Encountered an object $(s) of type $(typeof(s)) that can not be converted to $(repr) representation") # TODO make a nice error type
     end
-end
+end

test/test_aqua.jl

@@ -3,8 +3,8 @@
 
     # Add any new types needed to QObj, or here if QObj if not appropriate.
     # Add types from elsewhere in the ecosystem here or preferably to QObj
-    own_types = [Base.uniontypes(QObj)...,]
-    own_types_union = Union{SymQObj,}
+    own_types = [Base.uniontypes(QObj)...,AbstractRepresentation,AbstractUse,]
+    own_types_union = Union{SymQObj,AbstractRepresentation,AbstractUse,}
 
     Aqua.test_all(QuantumSymbolics, piracies=(;treat_as_own=own_types))