Network solvers redesign (#242)

Co-authored-by: Matt Fishman <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Jack Dunham <[email protected]>
Co-authored-by: Jack Dunham <[email protected]>

Author: 5 people

Project.toml

@@ -1,13 +1,15 @@
 name = "ITensorNetworks"
 uuid = "2919e153-833c-4bdc-8836-1ea460a35fc7"
 authors = ["Matthew Fishman <[email protected]>, Joseph Tindall <[email protected]> and contributors"]
-version = "0.14.2"
+version = "0.15.0"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"
+Accessors = "7d9f7c33-5ae7-4f3b-8dc6-eff91059b697"
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
 Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
 Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"
+ConstructionBase = "187b0558-2788-49d3-abe0-74a17ed4e7c9"
 DataGraphs = "b5a273c3-7e6c-41f6-98bd-8d7f1525a36a"
 DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
 Dictionaries = "85a47980-9c8c-11e8-2b9f-f7ca1fa99fb4"
@@ -49,9 +51,11 @@ ITensorNetworksTensorOperationsExt = "TensorOperations"
 
 [compat]
 AbstractTrees = "0.4.4"
+Accessors = "0.1.42"
 Adapt = "4"
 Combinatorics = "1"
 Compat = "3, 4"
+ConstructionBase = "1.6.0"
 DataGraphs = "0.2.3"
 DataStructures = "0.18, 0.19"
 Dictionaries = "0.4"

docs/Project.toml

@@ -5,5 +5,5 @@ Literate = "98b081ad-f1c9-55d3-8b20-4c87d4299306"
 
 [compat]
 Documenter = "1.10.0"
-ITensorNetworks = "0.14.0"
+ITensorNetworks = "0.15.0"
 Literate = "2.20.1"

examples/Project.toml

@@ -2,4 +2,4 @@
 ITensorNetworks = "2919e153-833c-4bdc-8836-1ea460a35fc7"
 
 [compat]
-ITensorNetworks = "0.14.0"
+ITensorNetworks = "0.15.0"

src/ITensorNetworks.jl

@@ -34,11 +34,7 @@ include("formnetworks/quadraticformnetwork.jl")
 include("gauging.jl")
 include("utils.jl")
 include("update_observer.jl")
-include("solvers/local_solvers/eigsolve.jl")
-include("solvers/local_solvers/exponentiate.jl")
-include("solvers/local_solvers/dmrg_x.jl")
-include("solvers/local_solvers/contract.jl")
-include("solvers/local_solvers/linsolve.jl")
+
 include("treetensornetworks/abstracttreetensornetwork.jl")
 include("treetensornetworks/treetensornetwork.jl")
 include("treetensornetworks/opsum_to_ttn/matelem.jl")
@@ -48,18 +44,29 @@ include("treetensornetworks/projttns/abstractprojttn.jl")
 include("treetensornetworks/projttns/projttn.jl")
 include("treetensornetworks/projttns/projttnsum.jl")
 include("treetensornetworks/projttns/projouterprodttn.jl")
-include("solvers/solver_utils.jl")
-include("solvers/defaults.jl")
-include("solvers/insert/insert.jl")
-include("solvers/extract/extract.jl")
-include("solvers/alternating_update/alternating_update.jl")
-include("solvers/alternating_update/region_update.jl")
-include("solvers/tdvp.jl")
-include("solvers/dmrg.jl")
-include("solvers/dmrg_x.jl")
-include("solvers/contract.jl")
-include("solvers/linsolve.jl")
-include("solvers/sweep_plans/sweep_plans.jl")
+
+include("solvers/local_solvers/eigsolve.jl")
+include("solvers/local_solvers/exponentiate.jl")
+include("solvers/local_solvers/runge_kutta.jl")
+include("solvers/truncation_parameters.jl")
+include("solvers/iterators.jl")
+include("solvers/adapters.jl")
+include("solvers/sweep_solve.jl")
+include("solvers/region_plans/dfs_plans.jl")
+include("solvers/region_plans/euler_tour.jl")
+include("solvers/region_plans/euler_plans.jl")
+include("solvers/region_plans/tdvp_region_plans.jl")
+include("solvers/extract.jl")
+include("solvers/insert.jl")
+include("solvers/subspace/subspace.jl")
+include("solvers/subspace/densitymatrix.jl")
+include("solvers/align_indices.jl")
+include("solvers/operator_map.jl")
+include("solvers/abstract_problem.jl")
+include("solvers/eigsolve.jl")
+include("solvers/applyexp.jl")
+include("solvers/fitting.jl")
+
 include("apply.jl")
 include("inner.jl")
 include("normalize.jl")

src/itensornetwork.jl

@@ -1,6 +1,6 @@
 using DataGraphs: DataGraphs, DataGraph
 using Dictionaries: Indices, dictionary
-using ITensors: ITensors, ITensor, op, state
+using ITensors: ITensors, ITensor, op
 using .ITensorsExtensions: trivial_space
 using NamedGraphs: NamedGraphs, NamedEdge, NamedGraph, vertextype
 
@@ -180,7 +180,7 @@ function generic_state(x::Op, inds::NamedTuple)
 end
 function generic_state(s::AbstractString, inds::NamedTuple)
   # TODO: Figure out what to do if there is more than one site.
-  site_tensors = [state(s, only(inds.siteinds))]
+  site_tensors = [ITensors.state(s, only(inds.siteinds))]
   link_tensors = [[onehot(i => 1) for i in inds.linkinds[e]] for e in keys(inds.linkinds)]
   return contract(reduce(vcat, link_tensors; init=site_tensors))
 end

src/solvers/abstract_problem.jl

@@ -0,0 +1,4 @@
+
+abstract type AbstractProblem end
+
+set_truncation_info!(P::AbstractProblem, args...; kws...) = P

src/solvers/adapters.jl

@@ -0,0 +1,46 @@
+"""
+  struct PauseAfterIncrement{S<:AbstractNetworkIterator}
+
+Iterator wrapper whos `compute!` function simply returns itself, doing nothing in the 
+process. This allows one to manually call a custom `compute!` or insert their own code it in
+the loop body in place of `compute!`.
+"""
+struct IncrementOnly{S<:AbstractNetworkIterator} <: AbstractNetworkIterator
+  parent::S
+end
+
+islaststep(adapter::IncrementOnly) = islaststep(adapter.parent)
+state(adapter::IncrementOnly) = state(adapter.parent)
+increment!(adapter::IncrementOnly) = increment!(adapter.parent)
+compute!(adapter::IncrementOnly) = adapter
+
+IncrementOnly(adapter::IncrementOnly) = adapter
+
+"""
+  struct EachRegion{SweepIterator} <: AbstractNetworkIterator
+
+Adapter that flattens each region iterator in the parent sweep iterator into a single
+iterator.
+"""
+struct EachRegion{SI<:SweepIterator} <: AbstractNetworkIterator
+  parent::SI
+end
+
+# In keeping with Julia convention.
+eachregion(iter::SweepIterator) = EachRegion(iter)
+
+# Essential definitions
+function islaststep(adapter::EachRegion)
+  region_iter = region_iterator(adapter.parent)
+  return islaststep(adapter.parent) && islaststep(region_iter)
+end
+function increment!(adapter::EachRegion)
+  region_iter = region_iterator(adapter.parent)
+  islaststep(region_iter) ? increment!(adapter.parent) : increment!(region_iter)
+  return adapter
+end
+function compute!(adapter::EachRegion)
+  region_iter = region_iterator(adapter.parent)
+  compute!(region_iter)
+  return adapter
+end

src/solvers/align_indices.jl

@@ -0,0 +1,16 @@
+
+function align_indices(tn)
+  si = siteinds(tn)
+  ptn = copy(tn)
+  for v in vertices(tn)
+    is = inds(tn[v])
+    ls = setdiff(is, si[v])
+    isempty(ls) && continue
+    new_is = [first(ls), si[v]...]
+    if length(ls) >= 2
+      new_is = vcat(new_is, ls[2:end])
+    end
+    ptn[v] = permute(tn[v], new_is)
+  end
+  return ptn
+end