rework default scheduler settings

Author: lkdvos

Project.toml

@@ -9,6 +9,7 @@ LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 OhMyThreads = "67456a42-1dca-4109-a031-0a68de7e3ad5"
 PackageExtensionCompat = "65ce6f38-6b18-4e1d-a461-8949797d7930"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+ScopedValues = "7e506255-f358-4e82-b7e4-beb19740aa63"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 Strided = "5e0ebb24-38b0-5f93-81fe-25c709ecae67"
 TensorKitSectors = "13a9c161-d5da-41f0-bcbd-e1a08ae0647f"
@@ -35,6 +36,7 @@ LinearAlgebra = "1"
 OhMyThreads = "0.7.0"
 PackageExtensionCompat = "1"
 Random = "1"
+ScopedValues = "1.3.0"
 SparseArrays = "1"
 Strided = "2"
 TensorKitSectors = "0.1"

src/TensorKit.jl

@@ -102,6 +102,7 @@ const TO = TensorOperations
 
 using LRUCache
 using OhMyThreads
+using ScopedValues
 
 using TensorKitSectors
 import TensorKitSectors: dim, BraidingStyle, FusionStyle, ⊠, ⊗
@@ -185,6 +186,7 @@ include("spaces/vectorspaces.jl")
 #-------------------------------------
 # general definitions
 include("tensors/abstracttensor.jl")
+include("tensors/backends.jl")
 include("tensors/blockiterator.jl")
 include("tensors/tensor.jl")
 include("tensors/adjoint.jl")

src/tensors/backends.jl

@@ -0,0 +1,27 @@
+# Scheduler implementation
+# ------------------------
+const blockscheduler = ScopedValue{Scheduler}(SerialScheduler())
+const subblockscheduler = ScopedValue{Scheduler}(SerialScheduler())
+
+# Backend implementation
+# ----------------------
+# TODO: figure out a name
+# TODO: what should be the default scheduler?
+@kwdef struct TensorKitBackend{B<:AbstractBackend,BS,SBS} <: AbstractBackend
+    arraybackend::B = TO.DefaultBackend()
+    blockscheduler::BS = blockscheduler[]
+    subblockscheduler::SBS = subblockscheduler[]
+end
+
+function TO.select_backend(::typeof(TO.tensoradd!), C::AbstractTensorMap,
+                           A::AbstractTensorMap)
+    return TensorKitBackend()
+end
+function TO.select_backend(::typeof(TO.tensortrace!), C::AbstractTensorMap,
+                           A::AbstractTensorMap)
+    return TensorKitBackend()
+end
+function TO.select_backend(::typeof(TO.tensorcontract!), C::AbstractTensorMap,
+                           A::AbstractTensorMap, B::AbstractTensorMap)
+    return TensorKitBackend()
+end

src/tensors/tensoroperations.jl

@@ -144,30 +144,6 @@ TO.tensorcost(t::AbstractTensorMap, i::Int) = dim(space(t, i))
 # IMPLEMENTATONS
 #----------------
 
-# Backend implementation
-# ----------------------
-# TODO: figure out a name
-# TODO: what should be the default scheduler?
-# TODO: should we allow a separate scheduler for "blocks" and "subblocks"
-@kwdef struct TensorKitBackend{B<:AbstractBackend,BS,SBS} <: AbstractBackend
-    arraybackend::B = TO.DefaultBackend()
-    blockscheduler::BS = SerialScheduler()
-    subblockscheduler::SBS = SerialScheduler()
-end
-
-function TO.select_backend(::typeof(TO.tensoradd!), C::AbstractTensorMap,
-                           A::AbstractTensorMap)
-    return TensorKitBackend()
-end
-function TO.select_backend(::typeof(TO.tensortrace!), C::AbstractTensorMap,
-                           A::AbstractTensorMap)
-    return TensorKitBackend()
-end
-function TO.select_backend(::typeof(TO.tensorcontract!), C::AbstractTensorMap,
-                           A::AbstractTensorMap, B::AbstractTensorMap)
-    return TensorKitBackend()
-end
-
 # Trace implementation
 #----------------------
 """