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Merged
mtfishman merged 1 commit into from
Apr 24, 2026
Merged

Trim direct ITensorMPS imports from tests, quarantine MPO cross-check #332

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2 changes: 1 addition & 1 deletion Project.toml
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
name = "ITensorNetworks"
uuid = "2919e153-833c-4bdc-8836-1ea460a35fc7"
version = "0.18.0"
version = "0.18.1"
authors = ["Matthew Fishman <mfishman@flatironinstitute.org>, Joseph Tindall <jtindall@flatironinstitute.org> and contributors"]

[workspace]
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2 changes: 1 addition & 1 deletion test/solvers/test_applyexp.jl
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using Graphs: add_edge!, add_vertex!, vertices
using ITensorMPS: OpSum
using ITensorNetworks:
ITensorNetworks, applyexp, dmrg, maxlinkdim, siteinds, time_evolve, ttn
using ITensors
using ITensors.Ops: OpSum
using NamedGraphs.NamedGraphGenerators: named_path_graph
using NamedGraphs: NamedGraph
using TensorOperations: TensorOperations
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2 changes: 1 addition & 1 deletion test/solvers/test_eigsolve.jl
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@@ -1,7 +1,7 @@
using Graphs: dst, edges, src, vertices
using ITensorMPS: OpSum
using ITensorNetworks: SweepIterator, dmrg, siteinds, ttn
using ITensors
using ITensors.Ops: OpSum
using Suppressor: @capture_out
using TensorOperations: TensorOperations
using Test: @test, @testset
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242 changes: 4 additions & 238 deletions test/test_opsum_to_ttn.jl
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@eval module $(gensym())
using DataGraphs: vertex_data
using Dictionaries: Dictionary, getindices
using Graphs: add_edge!, add_vertex!, rem_edge!, rem_vertex!, vertices
using ITensorMPS: ITensorMPS
using ITensorNetworks.ITensorsExtensions: replace_vertices
using ITensorNetworks.ModelHamiltonians: ModelHamiltonians
using Graphs: vertices
using ITensorNetworks: ITensorNetworks, OpSum, siteinds, ttn
using ITensors.NDTensors: matrix
using ITensors: ITensors, @disable_warn_order, ITensor, Index, combinedind, combiner,
contract, dag, inds, removeqns
using KrylovKit: eigsolve
using LinearAlgebra: eigvals, norm
using NamedGraphs.GraphsExtensions: leaf_vertices, post_order_dfs_vertices
using NamedGraphs.NamedGraphGenerators: named_comb_tree, named_grid
using Test: @test, @test_broken, @testset

function to_matrix(t::ITensor)
c = combiner(inds(t; plev = 0))
tc = (t * c) * dag(c')
cind = combinedind(c)
return matrix(tc, cind', cind)
end
using ITensors: ITensors
using NamedGraphs.NamedGraphGenerators: named_grid
using Test: @test, @testset

@testset "OpSum to TTN converter" begin
@testset "OpSum to TTN" begin
# small comb tree
auto_fermion_enabled = ITensors.using_auto_fermion()
tooth_lengths = fill(2, 3)
c = named_comb_tree(tooth_lengths)

is = siteinds("S=1/2", c)

# linearized version
linear_order = [4, 1, 2, 5, 3, 6]
vmap = Dictionary(collect(vertices(is))[linear_order], eachindex(linear_order))
sites = only.(collect(vertex_data(is)))[linear_order]

# test with next-to-nearest-neighbor Ising Hamiltonian
J1 = -1
J2 = 2
h = 0.5
H = ModelHamiltonians.ising(c; J1 = J1, J2 = J2, h = h)
# add combination of longer range interactions
Hlr = copy(H)
Hlr += 5, "Z", (1, 2), "Z", (2, 2), "Z", (3, 2)
Hlr += -4, "Z", (1, 1), "Z", (2, 2), "Z", (3, 1)
Hlr += 2.0, "Z", (2, 2), "Z", (3, 2)
Hlr += -1.0, "Z", (1, 2), "Z", (3, 1)

# root_vertex = (1, 2)
# println(leaf_vertices(is))

@testset "Svd approach" for root_vertex in leaf_vertices(is)
# get TTN Hamiltonian directly
Hsvd = ttn(H, is; root_vertex, cutoff = 1.0e-10)
# get corresponding MPO Hamiltonian
Hline = ITensorMPS.MPO(replace_vertices(v -> vmap[v], H), sites)
# compare resulting dense Hamiltonians
@disable_warn_order begin
Tttno = prod(Hline)
Tmpo = contract(Hsvd)
end
@test Tttno ≈ Tmpo rtol = 1.0e-6

Hsvd_lr = ttn(Hlr, is; root_vertex, cutoff = 1.0e-10)
Hline_lr = ITensorMPS.MPO(replace_vertices(v -> vmap[v], Hlr), sites)
@disable_warn_order begin
Tttno_lr = prod(Hline_lr)
Tmpo_lr = contract(Hsvd_lr)
end
@test Tttno_lr ≈ Tmpo_lr rtol = 1.0e-6
end
if auto_fermion_enabled
ITensors.enable_auto_fermion()
end
end

@testset "Multiple onsite terms (regression test for issue #62)" begin
auto_fermion_enabled = ITensors.using_auto_fermion()
if !auto_fermion_enabled
Expand All @@ -98,169 +28,5 @@ end
ITensors.enable_auto_fermion()
end
end

@testset "OpSum to TTN QN" begin
# small comb tree
tooth_lengths = fill(2, 3)
c = named_comb_tree(tooth_lengths)
is = siteinds("S=1/2", c; conserve_qns = true)
is_noqns = copy(is)
for v in vertices(is)
is_noqns[v] = removeqns(is_noqns[v])
end

# linearized version
linear_order = [4, 1, 2, 5, 3, 6]
vmap = Dictionary(collect(vertices(is))[linear_order], eachindex(linear_order))
sites = only.(collect(vertex_data(is)))[linear_order]

# test with next-to-nearest-neighbor Ising Hamiltonian
J1 = -1
J2 = 2
h = 0.5
H = ModelHamiltonians.heisenberg(c; J1 = J1, J2 = J2, h = h)
# add combination of longer range interactions
Hlr = copy(H)
Hlr += 5, "Z", (1, 2), "Z", (2, 2) #, "Z", (3,2)
Hlr += -4, "Z", (1, 1), "Z", (2, 2)
Hlr += 2.0, "Z", (2, 2), "Z", (3, 2)
Hlr += -1.0, "Z", (1, 2), "Z", (3, 1)

# root_vertex = (1, 2)
# println(leaf_vertices(is))

@testset "Svd approach" for root_vertex in leaf_vertices(is)
# get TTN Hamiltonian directly
Hsvd = ttn(H, is; root_vertex, cutoff = 1.0e-10)
# get corresponding MPO Hamiltonian
Hline = ITensorMPS.MPO(replace_vertices(v -> vmap[v], H), sites)
# compare resulting sparse Hamiltonians

@disable_warn_order begin
Tmpo = prod(Hline)
Tttno = contract(Hsvd)
end
@test Tttno ≈ Tmpo rtol = 1.0e-6

Hsvd_lr = ttn(Hlr, is; root_vertex, cutoff = 1.0e-10)
Hline_lr = ITensorMPS.MPO(replace_vertices(v -> vmap[v], Hlr), sites)
@disable_warn_order begin
Tttno_lr = prod(Hline_lr)
Tmpo_lr = contract(Hsvd_lr)
end
@test Tttno_lr ≈ Tmpo_lr rtol = 1.0e-6
end
end

@testset "OpSum to TTN Fermions" begin
# small comb tree
auto_fermion_enabled = ITensors.using_auto_fermion()
if !auto_fermion_enabled
ITensors.enable_auto_fermion()
end
tooth_lengths = fill(2, 3)
c = named_comb_tree(tooth_lengths)
is = siteinds("Fermion", c; conserve_nf = true)

# test with next-nearest neighbor tight-binding model
t = 1.0
tp = 0.4
U = 0.0
h = 0.5
H = ModelHamiltonians.tight_binding(c; t, tp, h)

# add combination of longer range interactions
Hlr = copy(H)

@testset "Svd approach" for root_vertex in leaf_vertices(is)
# get TTN Hamiltonian directly
Hsvd = ttn(H, is; root_vertex, cutoff = 1.0e-10)
# get corresponding MPO Hamiltonian
sites = [only(is[v]) for v in reverse(post_order_dfs_vertices(c, root_vertex))]
vmap = Dictionary(
reverse(post_order_dfs_vertices(c, root_vertex)),
1:length(sites)
)
Hline = ITensorMPS.MPO(replace_vertices(v -> vmap[v], H), sites)
@disable_warn_order begin
Tmpo = prod(Hline)
Tttno = contract(Hsvd)
end

# verify that the norm isn't 0 and thus the same (which would indicate a problem with the autofermion system
@test norm(Tmpo) > 0
@test norm(Tttno) > 0
@test norm(Tmpo) ≈ norm(Tttno) rtol = 1.0e-6

# TODO: fix comparison for fermionic tensors
@test_broken Tmpo ≈ Tttno
# In the meantime: matricize tensors and convert to dense Matrix to compare element by element
dTmm = to_matrix(Tmpo)
dTtm = to_matrix(Tttno)
@test any(>(1.0e-14), dTmm - dTtm)
end
if !auto_fermion_enabled
ITensors.disable_auto_fermion()
end
end

@testset "OpSum to TTN QN missing" begin
# small comb tree
tooth_lengths = fill(2, 3)
c = named_comb_tree(tooth_lengths)
c2 = copy(c)
## add an internal vertex into the comb graph c2
add_vertex!(c2, (-1, 1))
add_edge!(c2, (-1, 1) => (2, 2))
add_edge!(c2, (-1, 1) => (3, 1))
add_edge!(c2, (-1, 1) => (2, 1))
rem_edge!(c2, (2, 1) => (2, 2))
rem_edge!(c2, (2, 1) => (3, 1))

is = siteinds("S=1/2", c; conserve_qns = true)
is_missing_site = siteinds("S=1/2", c2; conserve_qns = true)
is_missing_site[(-1, 1)] = Vector{Index}[]

# linearized version
linear_order = [4, 1, 2, 5, 3, 6]
vmap = Dictionary(collect(vertices(is))[linear_order], eachindex(linear_order))
sites =
only.(filter(d -> !isempty(d), collect(vertex_data(is_missing_site))))[linear_order]

J1 = -1
J2 = 2
h = 0.5
# connectivity of the Hamiltonian is that of the original comb graph
H = ModelHamiltonians.heisenberg(c; J1, J2, h)

# add combination of longer range interactions
Hlr = copy(H)
Hlr += 5, "Z", (1, 2), "Z", (2, 2)
Hlr += -4, "Z", (1, 1), "Z", (2, 2)
Hlr += 2.0, "Z", (2, 2), "Z", (3, 2)
Hlr += -1.0, "Z", (1, 2), "Z", (3, 1)

@testset "Svd approach" for root_vertex in leaf_vertices(is)
# get TTN Hamiltonian directly
Hsvd = ttn(H, is_missing_site; root_vertex, cutoff = 1.0e-10)
# get corresponding MPO Hamiltonian
Hline = ITensorMPS.MPO(replace_vertices(v -> vmap[v], H), sites)

# compare resulting sparse Hamiltonians
@disable_warn_order begin
Tmpo = prod(Hline)
Tttno = contract(Hsvd)
end
@test Tttno ≈ Tmpo rtol = 1.0e-6

Hsvd_lr = ttn(Hlr, is_missing_site; root_vertex, cutoff = 1.0e-10)
Hline_lr = ITensorMPS.MPO(replace_vertices(v -> vmap[v], Hlr), sites)
@disable_warn_order begin
Tttno_lr = prod(Hline_lr)
Tmpo_lr = contract(Hsvd_lr)
end
@test Tttno_lr ≈ Tmpo_lr rtol = 1.0e-6
end
end
end
end
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