From 49448aea8f5b4aa0dbc3e9effc856fa04ab4de26 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sergio=20S=C3=A1nchez=20Ram=C3=ADrez?=
 <sergio.sanchez.ramirez+git@bsc.es>
Date: Thu, 28 Dec 2023 16:19:30 +0100
Subject: [PATCH] Refactor `selectdim` and slicing methods for `SizedEinExpr`

---
 src/Slicing.jl       | 56 +++++++++++++++++++++-----------------------
 test/Slicing_test.jl |  5 ++--
 2 files changed, 30 insertions(+), 31 deletions(-)

diff --git a/src/Slicing.jl b/src/Slicing.jl
index 82e6b07..281ecf3 100644
--- a/src/Slicing.jl
+++ b/src/Slicing.jl
@@ -13,34 +13,33 @@ Project `index` to dimension `i` in a EinExpr. This is equivalent to tensor cutt
 
 See also: [`view`](@ref).
 """
-function Base.selectdim(path::EinExpr, index::Symbol, i)
+Base.selectdim(path::EinExpr, ::Symbol, i) = path
+
+function Base.selectdim(path::EinExpr, index::Symbol, i::Integer)
     path = deepcopy(path)
 
-    for leave in Iterators.filter(∋(index) ∘ head, Leaves(path))
-        leave.size[index] = length(i)
+    for expr in PreOrderDFS(path)
+        filter!(!=(index), expr.head)
     end
 
     return path
 end
 
-function Base.selectdim(path::EinExpr, index::Symbol, _::Integer)
-    path = deepcopy(path)
+function Base.selectdim(sexpr::SizedEinExpr, index::Symbol, i)
+    path = selectdim(sexpr.path, index, i)
 
-    index ∈ head(path) && (path = EinExpr(filter(!=(index), path.head), path.args))
-
-    for branch in Branches(path)
-        for arg in Iterators.filter(∋(index) ∘ head, branch.args)
-            replace!(
-                branch.args,
-                arg => EinExpr(
-                    filter(!=(index), arg.head),
-                    isempty(arg.args) ? filter(p -> p.first != index, arg.size) : arg.args,
-                ),
-            )
-        end
-    end
+    size = copy(sexpr.size)
+    size[index] = length(i)
 
-    return path
+    return SizedEinExpr(path, size)
+end
+
+function Base.selectdim(sexpr::SizedEinExpr, index::Symbol, i::Integer)
+    path = selectdim(sexpr.path, index, i)
+
+    size = filter(!=(index) ∘ first, sexpr.size)
+
+    return SizedEinExpr(path, size)
 end
 
 """
@@ -88,8 +87,7 @@ Reimplementation based on [`contengra`](https://github.com/jcmgray/cotengra)'s `
 """
 function findslices(
     scorer,
-    path::EinExpr,
-    sizedict;
+    path;
     size = nothing,
     overhead = nothing,
     slices = nothing,
@@ -101,8 +99,8 @@ function findslices(
 
     candidates = Set(setdiff(mapreduce(head, ∪, PostOrderDFS(path)), skip))
     solution = Set{Symbol}()
-    current = (; slices = 1, size = maximum(Base.Fix2(length, sizedict), PostOrderDFS(path)), overhead = 1.0)
-    original_flops = mapreduce(flops(sizedict), +, Branches(path; inverse = true))
+    current = (; slices = 1, size = maximum(length, PostOrderDFS(path)), overhead = 1.0)
+    original_flops = mapreduce(flops, +, Branches(path; inverse = true))
 
     sliced_path = path
     while !isempty(candidates)
@@ -114,15 +112,15 @@ function findslices(
 
         sliced_path = selectdim(sliced_path, winner, 1)
         cur_overhead =
-            prod(i -> sizedict[i], [solution..., winner]) *
-            mapreduce(flops(sizedict), +, Branches(sliced_path; inverse = true)) / original_flops
+            prod(i -> Base.size(path, i), [solution..., winner]) *
+            mapreduce(flops, +, Branches(sliced_path; inverse = true)) / original_flops
 
         !isnothing(overhead) && cur_overhead > overhead && break
         push!(solution, winner)
 
         current = (;
-            slices = current.slices * Base.Fix2(length, sizedict)(path, winner),
-            size = maximum(Base.Fix2(length, sizedict), PostOrderDFS(sliced_path)),
+            slices = current.slices * Base.size(path, winner),
+            size = maximum(length, PostOrderDFS(sliced_path)),
             overhead = cur_overhead,
         )
 
@@ -150,7 +148,7 @@ function (cb::FlopsScorer)(path, index)
     slice = selectdim(path, index, 1)
 
     flops_reduction = mapreduce(flops, +, PostOrderDFS(path)) - mapreduce(flops, +, PostOrderDFS(slice))
-    write_reduction = mapreduce(prod ∘ size, +, PostOrderDFS(path)) - mapreduce(prod ∘ size, +, PostOrderDFS(slice))
+    write_reduction = mapreduce(length, +, PostOrderDFS(path)) - mapreduce(length, +, PostOrderDFS(slice))
 
     log(flops_reduction + write_reduction * cb.weight + 1)
 end
@@ -170,7 +168,7 @@ function (cb::SizeScorer)(path, index)
     slice = selectdim(path, index, 1)
 
     flops_reduction = mapreduce(flops, +, PostOrderDFS(path)) - mapreduce(flops, +, PostOrderDFS(slice))
-    write_reduction = mapreduce(prod ∘ size, +, PostOrderDFS(path)) - mapreduce(prod ∘ size, +, PostOrderDFS(slice))
+    write_reduction = mapreduce(length, +, PostOrderDFS(path)) - mapreduce(length, +, PostOrderDFS(slice))
 
     log(write_reduction + flops_reduction * cb.weight + 1)
 end
diff --git a/test/Slicing_test.jl b/test/Slicing_test.jl
index 6e9f6ef..5980863 100644
--- a/test/Slicing_test.jl
+++ b/test/Slicing_test.jl
@@ -65,8 +65,9 @@
             EinExpr((:p, :k)),
         ],
     )
+    sexpr = SizedEinExpr(expr, sizes)
 
-    cuttings = findslices(FlopsScorer(), expr, slices = 1000)
+    cuttings = findslices(FlopsScorer(), sexpr, slices = 1000)
 
-    @test prod(i -> sizedict[i], cuttings) >= 1000
+    @test prod(i -> sizes[i], cuttings) >= 1000
 end