Let approx_itensornetwork support complex tensor network (#81)

ITensor · Apr 7, 2023 · bb36a6a · bb36a6a
1 parent 756d09b
commit bb36a6a
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Showing 2 changed files with 35 additions and 27 deletions.
diff --git a/src/approx_itensornetwork.jl b/src/approx_itensornetwork.jl
@@ -166,9 +166,9 @@ end
 function _get_low_rank_projector(tensor, inds1, inds2; cutoff, maxdim)
   @assert length(inds(tensor)) <= 4
   @timeit_debug ITensors.timer "[approx_binary_tree_itensornetwork]: eigen" begin
-    diag, U = eigen(tensor, inds1, inds2; cutoff=cutoff, maxdim=maxdim, ishermitian=true)
+    F = eigen(tensor, inds1, inds2; cutoff=cutoff, maxdim=maxdim, ishermitian=true)
   end
-  return U
+  return F.Vt
 end
 
 """
@@ -233,16 +233,19 @@ function _update!(
   end
   if length(pdms) == 0
     sim_network = map(x -> replaceinds(x, inds_to_sim), network)
+    sim_network = map(dag, sim_network)
     density_matrix = _optcontract(
       [network..., sim_network...]; contraction_sequence_alg, contraction_sequence_kwargs
     )
   elseif length(pdms) == 1
     sim_network = map(x -> replaceinds(x, inds_to_sim), network)
+    sim_network = map(dag, sim_network)
     density_matrix = _optcontract(
       [pdms[1], sim_network...]; contraction_sequence_alg, contraction_sequence_kwargs
     )
   else
     simtensor = _sim(pdms[2], inds_to_sim)
+    simtensor = dag(simtensor)
     density_matrix = _optcontract(
       [pdms[1], simtensor]; contraction_sequence_alg, contraction_sequence_kwargs
     )
@@ -305,14 +308,14 @@ function _rem_vertex!(
   end
   U = _get_low_rank_projector(
     caches.e_to_dm[NamedEdge(nothing, root)],
-    collect(values(outinds_root_to_sim)),
-    collect(keys(outinds_root_to_sim));
+    collect(keys(outinds_root_to_sim)),
+    collect(values(outinds_root_to_sim));
     cutoff,
     maxdim,
   )
   # update partition and out_tree
   root_tensor = _optcontract(
-    [Vector{ITensor}(alg_graph.partition[root])..., U];
+    [Vector{ITensor}(alg_graph.partition[root])..., dag(U)];
     contraction_sequence_alg,
     contraction_sequence_kwargs,
   )

diff --git a/test/test_binary_tree_partition.jl b/test/test_binary_tree_partition.jl
@@ -60,26 +60,31 @@ end
   k = Index(2, "k")
   l = Index(2, "l")
   m = Index(2, "m")
-  T = randomITensor(i, j, k, l, m)
-  M = MPS(T, (i, j, k, l, m); cutoff=1e-5, maxdim=5)
-  network = M[:]
-  out1 = contract(network...)
-  tn = ITensorNetwork(network)
-  inds_btree = binary_tree_structure(tn)
-  par = partition(tn, inds_btree; alg="mincut_recursive_bisection")
-  par = _contract_deltas_ignore_leaf_partitions(par; root=_root(inds_btree))
-  networks = [Vector{ITensor}(par[v]) for v in vertices(par)]
-  network2 = vcat(networks...)
-  out2 = contract(network2...)
-  @test isapprox(out1, out2)
-  # test approx_itensornetwork
-  approx_tn, lognorm = approx_itensornetwork(
-    tn, binary_tree_structure; alg="density_matrix", contraction_sequence_alg="sa_bipartite"
-  )
-  network3 = Vector{ITensor}(approx_tn)
-  out3 = contract(network3...) * exp(lognorm)
-  i1 = noncommoninds(network...)
-  i3 = noncommoninds(network3...)
-  @test (length(i1) == length(i3))
-  @test isapprox(out1, out3)
+  for dtype in [Float64, ComplexF64]
+    T = randomITensor(dtype, i, j, k, l, m)
+    M = MPS(T, (i, j, k, l, m); cutoff=1e-5, maxdim=5)
+    network = M[:]
+    out1 = contract(network...)
+    tn = ITensorNetwork(network)
+    inds_btree = binary_tree_structure(tn)
+    par = partition(tn, inds_btree; alg="mincut_recursive_bisection")
+    par = _contract_deltas_ignore_leaf_partitions(par; root=_root(inds_btree))
+    networks = [Vector{ITensor}(par[v]) for v in vertices(par)]
+    network2 = vcat(networks...)
+    out2 = contract(network2...)
+    @test isapprox(out1, out2)
+    # test approx_itensornetwork
+    approx_tn, lognorm = approx_itensornetwork(
+      tn,
+      binary_tree_structure;
+      alg="density_matrix",
+      contraction_sequence_alg="sa_bipartite",
+    )
+    network3 = Vector{ITensor}(approx_tn)
+    out3 = contract(network3...) * exp(lognorm)
+    i1 = noncommoninds(network...)
+    i3 = noncommoninds(network3...)
+    @test (length(i1) == length(i3))
+    @test isapprox(out1, out3)
+  end
 end