[ITensors] Observers.jl package extension (#1381)

.github/workflows/test_itensortdvp_ubuntu.yml

@@ -0,0 +1,53 @@
+name: Run ITensorTDVP tests (Unbuntu)
+
+on:
+  push:
+    branches:
+      - main
+    tags: '*'
+  pull_request:
+
+jobs:
+  test:
+    name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ matrix.threads }} thread(s)
+    runs-on: ${{ matrix.os }}
+    env:
+      JULIA_NUM_THREADS: ${{ matrix.threads }}
+    strategy:
+      matrix:
+        version:
+          - '1.6'
+          - '1'
+        os:
+          - ubuntu-latest
+        threads:
+          - '2'
+        arch:
+          - x64
+        exclude:
+          # MacOS not available on x86
+          - {os: 'macOS-latest', arch: 'x86'}
+    steps:
+      - uses: actions/checkout@v2
+      - uses: julia-actions/setup-julia@latest
+        with:
+          version: ${{ matrix.version }}
+          arch: ${{ matrix.arch }}
+      - name: Install Julia dependencies and run tests
+        shell: julia {0}
+        run: |
+          using Pkg;
+          try
+            Pkg.activate(temp=true);
+            Pkg.develop(path="./NDTensors");
+            Pkg.develop(path=".");
+            Pkg.add("ITensorTDVP");
+            Pkg.test("ITensorTDVP");
+          catch err
+            err isa Pkg.Resolve.ResolverError || rethrow()
+            # If we can't resolve that means this is incompatible by SemVer and this is fine
+            # It means we marked this as a breaking change, so we don't need to worry about
+            # Mistakenly introducing a breaking change, as we have intentionally made one
+            @info "ITensorTDVP not compatible with this release. Skipping this test." exception=err
+            exit(0)  # Exit immediately, as a success
+          end

Project.toml

@@ -34,9 +34,11 @@ Zeros = "bd1ec220-6eb4-527a-9b49-e79c3db6233b"
 ZygoteRules = "700de1a5-db45-46bc-99cf-38207098b444"
 
 [weakdeps]
+Observers = "338f10d5-c7f1-4033-a7d1-f9dec39bcaa0"
 VectorInterface = "409d34a3-91d5-4945-b6ec-7529ddf182d8"
 
 [extensions]
+ITensorsObserversExt = "Observers"
 ITensorsVectorInterfaceExt = "VectorInterface"
 
 [compat]
@@ -72,4 +74,5 @@ ZygoteRules = "0.2.2"
 julia = "1.6"
 
 [extras]
+Observers = "338f10d5-c7f1-4033-a7d1-f9dec39bcaa0"
 VectorInterface = "409d34a3-91d5-4945-b6ec-7529ddf182d8"

ext/ITensorsObserversExt/ITensorsObserversExt.jl

@@ -0,0 +1,11 @@
+module ITensorsObserversExt
+
+using Observers: Observers
+using Observers.DataFrames: AbstractDataFrame
+using ITensors.ITensorMPS: ITensorMPS
+
+function ITensorMPS.update_observer!(observer::AbstractDataFrame; kwargs...)
+  return Observers.update!(observer; kwargs...)
+end
+
+end

src/ITensorMPS/alternating_update.jl

@@ -98,7 +98,7 @@ function alternating_update(
       )
     end
     current_time += time_step
-    update!(step_observer!; psi, sweep, outputlevel, current_time)
+    update_observer!(step_observer!; psi, sweep, outputlevel, current_time)
     if outputlevel >= 1
       print("After sweep ", sweep, ":")
       print(" maxlinkdim=", maxlinkdim(psi))