embed for single-qubit and two-qubit symbolic Clifford Operator

src/dense_cliffords.jl

@@ -104,6 +104,48 @@ function apply!(r::CliffordOperator, l::AbstractCliffordOperator; phases=false)
     r
 end
 
+"""
+Embed a single-qubit Clifford operator in a larger Clifford operator.
+
+```jldoctest
+julia> embed(5, 4, sHadamard)
+X₁ ⟼ + X____
+X₂ ⟼ + _X___
+X₃ ⟼ + __X__
+X₄ ⟼ + ___Z_
+X₅ ⟼ + ____X
+Z₁ ⟼ + Z____
+Z₂ ⟼ + _Z___
+Z₃ ⟼ + __Z__
+Z₄ ⟼ + ___X_
+Z₅ ⟼ + ____Z
+```
+
+Embed a two-qubit Clifford operator in a larger Clifford operator.
+
+```jldoctest
+julia> embed(5, (2,3), sCNOT)
+X₁ ⟼ + X____
+X₂ ⟼ + _XX__
+X₃ ⟼ + __X__
+X₄ ⟼ + ___X_
+X₅ ⟼ + ____X
+Z₁ ⟼ + Z____
+Z₂ ⟼ + _Z___
+Z₃ ⟼ + _ZZ__
+Z₄ ⟼ + ___Z_
+Z₅ ⟼ + ____Z
+```
+"""
+function embed(n::Int, i::Int, t::DataType)
+    return CliffordOperator(t(i), n)
+end
+
+function embed(n::Int, indices::Tuple{Int,Int}, t::DataType)
+    i, j = collect(indices)
+    return CliffordOperator(t(i, j), n)
+end
+
 # TODO create Base.permute! and getindex(..., permutation_array)
 function permute(c::CliffordOperator,p) # TODO this is a slow stupid implementation
     CliffordOperator(Tableau([tab(c)[i][p] for i in 1:2*nqubits(c)][vcat(p,p.+nqubits(c))]))