fix kron and repeat over unitary channel

QuantumBFS · Oct 7, 2023 · 207570e · 207570e
1 parent 2db9961
commit 207570e
Show file tree

Hide file tree

Showing 3 changed files with 13 additions and 3 deletions.
diff --git a/lib/YaoBlocks/src/channel/unitary_channel.jl b/lib/YaoBlocks/src/channel/unitary_channel.jl
@@ -50,6 +50,7 @@ function YaoAPI.unsafe_apply!(r::DensityMatrix{D,T},
     for (locs, block) in zip(k.locs, k.blocks)
         YaoAPI.unsafe_apply!(r, put(k.n, locs => block))
     end
+    return r
 end
 
 function mat(::Type{T}, x::UnitaryChannel) where {T}

diff --git a/lib/YaoBlocks/src/composite/repeated.jl b/lib/YaoBlocks/src/composite/repeated.jl
@@ -128,9 +128,8 @@ mat(::Type{T}, rb::RepeatedBlock{D}) where {T,D} =
 mat(::Type{T}, rb::RepeatedBlock{D,0,GT}) where {T,D,GT} = IMatrix{T}(D^nqudits(rb))
 
 function YaoAPI.unsafe_apply!(r::AbstractRegister, rp::RepeatedBlock)
-    m = mat_matchreg(r, rp.content)
     for addr in rp.locs
-        instruct!(r, m, Tuple(addr:addr+nqudits(rp.content)-1))
+        YaoAPI.unsafe_apply!(r, put(nqudits(rp), addr:addr+nqudits(rp.content)-1=>rp.content))
     end
     return r
 end

diff --git a/lib/YaoBlocks/test/channel/unitary_channel.jl b/lib/YaoBlocks/test/channel/unitary_channel.jl
@@ -49,4 +49,14 @@ end
     ops = unitary_channel([put(2, 1=>chain(Rx(0.4), Ry(0.5), Rz(0.4))), put(2,2=>Y), put(2,1=>Z)], [0.3, 0.1, 0.6])
     channel2 = put(6, (2,3)=>ops)
     @test apply(r, channel1) ≈ apply(r, channel2)
-end
+end
+
+@testset "kron and repeat" begin
+    dm = density_matrix(ghz_state(5), 1:3)
+    dpolarizing = single_qubit_depolarizing_channel(0.1)
+    dmkron = apply(dm, kron(3, 1=>dpolarizing, 2=>dpolarizing))
+    dmrepeat = apply(dm, repeat(3, dpolarizing, (1, 2)))
+    dmput = apply(apply(dm, put(3, 1=>dpolarizing)), put(3, 2=>dpolarizing))
+    @test dmkron ≈ dmrepeat
+    @test dmkron ≈ dmput
+end