[AlgorithmSelection] Rename BackendSelection, introduce Backend type (#…

…1407)

NDTensors/src/blocksparse/contract.jl

@@ -1,4 +1,4 @@
-using .AlgorithmSelection: Algorithm, @Algorithm_str
+using .BackendSelection: Algorithm, @Algorithm_str
 
 function contract(
   tensor1::BlockSparseTensor,

NDTensors/src/imports.jl

@@ -22,8 +22,8 @@ using TimerOutputs
 using TupleTools
 
 for lib in [
-  :AlgorithmSelection,
   :AllocateData,
+  :BackendSelection,
   :BaseExtensions,
   :UnspecifiedTypes,
   :TypeParameterAccessors,
@@ -51,6 +51,10 @@ for lib in [
   include("lib/$(lib)/src/$(lib).jl")
   @eval using .$lib: $lib
 end
+# TODO: This is defined for backwards compatibility,
+# delete this alias once downstream packages change over
+# to using `BackendSelection`.
+const AlgorithmSelection = BackendSelection
 
 using Base: @propagate_inbounds, ReshapedArray, DimOrInd, OneTo
 

NDTensors/src/lib/BackendSelection/src/BackendSelection.jl

@@ -0,0 +1,9 @@
+module BackendSelection
+include("abstractbackend.jl")
+include("backend_types.jl")
+
+# TODO: This is defined for backwards compatibility,
+# delete this alias once downstream packages change over
+# to using `BackendSelection`.
+const AlgorithmSelection = BackendSelection
+end

NDTensors/src/lib/BackendSelection/src/abstractbackend.jl

@@ -0,0 +1,4 @@
+abstract type AbstractBackend end
+
+backend_string(::AbstractBackend) = error("Not implemented")
+parameters(::AbstractBackend) = error("Not implemented")

NDTensors/src/lib/BackendSelection/src/backend_types.jl

@@ -0,0 +1,57 @@
+for type in (:Algorithm, :Backend)
+  @eval begin
+    """
+        $($type)
+
+    A type representing a backend for a function.
+
+    For example, a function might have multiple backends
+    implementations, which internally are selected with a `$($type)` type.
+
+    This allows users to extend functionality with a new implementation but
+    use the same interface.
+    """
+    struct $type{Back,Kwargs<:NamedTuple} <: AbstractBackend
+      kwargs::Kwargs
+    end
+
+    $type{Back}(kwargs::NamedTuple) where {Back} = $type{Back,typeof(kwargs)}(kwargs)
+    $type{Back}(; kwargs...) where {Back} = $type{Back}(NamedTuple(kwargs))
+    $type(s; kwargs...) = $type{Symbol(s)}(NamedTuple(kwargs))
+
+    $type(backend::$type) = backend
+
+    # TODO: Use `SetParameters`.
+    backend_string(::$type{Back}) where {Back} = string(Back)
+    parameters(backend::$type) = getfield(backend, :kwargs)
+
+    function Base.show(io::IO, backend::$type)
+      return print(io, "$type type ", backend_string(backend), ", ", parameters(backend))
+    end
+    Base.print(io::IO, backend::$type) =
+      print(io, backend_string(backend), ", ", parameters(backend))
+  end
+end
+
+# TODO: See if these can be moved inside of `@eval`.
+"""
+    @Algorithm_str
+
+A convenience macro for writing [`Algorithm`](@ref) types, typically used when
+adding methods to a function that supports multiple algorithm
+backends.
+"""
+macro Algorithm_str(s)
+  return :(Algorithm{$(Expr(:quote, Symbol(s)))})
+end
+
+"""
+    @Backend_str
+
+A convenience macro for writing [`Backend`](@ref) types, typically used when
+adding methods to a function that supports multiple
+backends.
+"""
+macro Backend_str(s)
+  return :(Backend{$(Expr(:quote, Symbol(s)))})
+end

NDTensors/src/lib/BackendSelection/test/runtests.jl

@@ -0,0 +1,28 @@
+@eval module $(gensym())
+using Test: @test, @testset
+using NDTensors: NDTensors
+using NDTensors.BackendSelection:
+  BackendSelection, Algorithm, Backend, @Algorithm_str, @Backend_str
+# TODO: This is defined for backwards compatibility,
+# delete this alias once downstream packages change over
+# to using `BackendSelection`.
+using NDTensors.AlgorithmSelection: AlgorithmSelection
+@testset "BackendSelection" begin
+  # TODO: This is defined for backwards compatibility,
+  # delete this alias once downstream packages change over
+  # to using `BackendSelection`.
+  @test AlgorithmSelection === BackendSelection
+  for type in (Algorithm, Backend)
+    @testset "$type" begin
+      @test type("backend") isa type{:backend}
+      @test type(:backend) isa type{:backend}
+      backend = type("backend"; x=2, y=3)
+      @test backend isa type{:backend}
+      @test BackendSelection.parameters(backend) === (; x=2, y=3)
+    end
+  end
+  # Macro syntax.
+  @test Algorithm"backend"(; x=2, y=3) === Algorithm("backend"; x=2, y=3)
+  @test Backend"backend"(; x=2, y=3) === Backend("backend"; x=2, y=3)
+end
+end

NDTensors/src/lib/BlockSparseArrays/src/backup/BlockSparseArrays.jl

@@ -1,5 +1,5 @@
 module BlockSparseArrays
-using ..AlgorithmSelection: Algorithm, @Algorithm_str
+using ..BackendSelection: Algorithm, @Algorithm_str
 using BlockArrays:
   AbstractBlockArray,
   BlockArrays,

NDTensors/src/lib/BlockSparseArrays/src/backup/LinearAlgebraExt/LinearAlgebraExt.jl

@@ -1,5 +1,5 @@
 module LinearAlgebraExt
-using ...AlgorithmSelection: Algorithm, @Algorithm_str
+using ...BackendSelection: Algorithm, @Algorithm_str
 using BlockArrays: BlockArrays, blockedrange, blocks
 using ..BlockSparseArrays: nonzero_keys # TODO: Move to `SparseArraysExtensions` module, rename `SparseArrayDOK`.
 using ..BlockSparseArrays: BlockSparseArrays, BlockSparseArray, nonzero_blockkeys

NDTensors/src/lib/TensorAlgebra/src/contract/blockedperms.jl

@@ -1,4 +1,4 @@
-using ..AlgorithmSelection: Algorithm
+using ..BackendSelection: Algorithm
 using .BaseExtensions: BaseExtensions
 
 function blockedperms(

NDTensors/src/lib/TensorAlgebra/src/contract/contract.jl

@@ -1,4 +1,4 @@
-using ..AlgorithmSelection: Algorithm, @Algorithm_str
+using ..BackendSelection: Algorithm, @Algorithm_str
 
 # TODO: Add `contract!!` definitions as pass-throughs to `contract!`.
 

NDTensors/src/lib/TensorAlgebra/src/contract/contract_matricize/contract.jl

@@ -1,4 +1,4 @@
-using ..AlgorithmSelection: @Algorithm_str
+using ..BackendSelection: @Algorithm_str
 using LinearAlgebra: mul!
 
 function contract!(

NDTensors/src/lib/TensorAlgebra/src/contract/output_labels.jl

@@ -1,4 +1,4 @@
-using ..AlgorithmSelection: Algorithm
+using ..BackendSelection: Algorithm
 
 function output_labels(
   f::typeof(contract),

NDTensors/test/lib/runtests.jl

@@ -2,9 +2,9 @@
 using NDTensors: NDTensors
 using Test: @testset
 @testset "Test NDTensors lib $lib" for lib in [
-  "AlgorithmSelection",
   "AllocateData",
   "AMDGPUExtensions",
+  "BackendSelection",
   "BaseExtensions",
   "BlockSparseArrays",
   "BroadcastMapConversion",