From 1f1e51917a392feba759efb1b7227da148f332e4 Mon Sep 17 00:00:00 2001
From: Marek Kaluba <kalmar@amu.edu.pl>
Date: Wed, 22 Mar 2023 21:41:37 +0100
Subject: [PATCH] remove threaded wlmetric_ball

* the threaded version was hardly faster
* there was a memory leak (?) that was gone with -t 1
* simplifies the whole thing
---
 Project.toml     |  5 ++--
 src/Groups.jl    |  5 +---
 src/iteration.jl |  2 ++
 src/wl_ball.jl   | 72 ++++++++++++++----------------------------------
 4 files changed, 26 insertions(+), 58 deletions(-)

diff --git a/Project.toml b/Project.toml
index 6b177eb..6e57613 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,20 +1,19 @@
 name = "Groups"
 uuid = "5d8bd718-bd84-11e8-3b40-ad14f4a32557"
 authors = ["Marek Kaluba <kalmar@amu.edu.pl>"]
-version = "0.7.5"
+version = "0.7.6"
 
 [deps]
-Folds = "41a02a25-b8f0-4f67-bc48-60067656b558"
 GroupsCore = "d5909c97-4eac-4ecc-a3dc-fdd0858a4120"
 KnuthBendix = "c2604015-7b3d-4a30-8a26-9074551ec60a"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
 OrderedCollections = "bac558e1-5e72-5ebc-8fee-abe8a469f55d"
 PermutationGroups = "8bc5a954-2dfc-11e9-10e6-cd969bffa420"
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 
 [compat]
-Folds = "0.2.7"
 GroupsCore = "0.4"
 KnuthBendix = "0.4"
 OrderedCollections = "1"
diff --git a/src/Groups.jl b/src/Groups.jl
index 96c7d09..9237429 100644
--- a/src/Groups.jl
+++ b/src/Groups.jl
@@ -1,12 +1,9 @@
 module Groups
 
-import Folds
 import Logging
 
 using GroupsCore
-import GroupsCore.Random
-
-import OrderedCollections: OrderedSet
+import Random
 
 import KnuthBendix
 import KnuthBendix: AbstractWord, Alphabet, Word
diff --git a/src/iteration.jl b/src/iteration.jl
index 210289b..e3028fb 100644
--- a/src/iteration.jl
+++ b/src/iteration.jl
@@ -1,3 +1,5 @@
+import OrderedCollections: OrderedSet
+
 mutable struct FPGroupIter{S,T,GEl}
     seen::S
     seen_iter_state::T
diff --git a/src/wl_ball.jl b/src/wl_ball.jl
index ae8db7d..96b5984 100644
--- a/src/wl_ball.jl
+++ b/src/wl_ball.jl
@@ -1,6 +1,6 @@
 """
     wlmetric_ball(S::AbstractVector{<:GroupElem}
-        [, center=one(first(S)); radius=2, op=*, threading=true])
+        [, center=one(first(S)); radius=2, op=*])
 Compute metric ball as a list of elements of non-decreasing length, given the
 word-length metric on the group generated by `S`. The ball is centered at `center`
 (by default: the identity element). `radius` and `op` keywords specify the
@@ -11,57 +11,27 @@ function wlmetric_ball(
     center::T = one(first(S));
     radius = 2,
     op = *,
-    threading = true,
 ) where {T}
-    threading && return wlmetric_ball_thr(S, center; radius = radius, op = op)
-    return wlmetric_ball_serial(S, center; radius = radius, op = op)
-end
-
-function wlmetric_ball_serial(
-    S::AbstractVector{T},
-    center::T = one(first(S));
-    radius = 2,
-    op = *,
-) where {T}
-    @assert radius >= 1
-    old = union!(OrderedSet([center]), [center * s for s in S])
-    sizes = [1, length(old)]
-    for _ in 2:radius
-        new = collect(
-            op(o, s) for o in @view(old.dict.keys[sizes[end-1]:end]) for s in S
-        )
-        union!(old, new)
-        push!(sizes, length(old))
-    end
-    return old.dict.keys, sizes[2:end]
-end
-
-function wlmetric_ball_thr(
-    S::AbstractVector{T},
-    center::T = one(first(S));
-    radius = 2,
-    op = *,
-) where {T}
-    @assert radius >= 1
-    old = union!([center], [center * s for s in S])
-    return _wlmetric_ball(S, old, radius, op, Folds.collect, Folds.unique)
-end
-
-function _wlmetric_ball(S, old, radius, op, collect, unique)
-    sizes = [1, length(old)]
-    for _ in 2:radius
-        old = let old = old, S = S
-            new = collect(
-                (g = op(o, s);
-                normalform!(g);
-                hash(g);
-                g) for o in @view(old[sizes[end-1]:end]) for s in S
-            )
-
-            append!(old, new)
-            unique(old)
+    ball = [center]
+    sizes = [1]
+    if radius ≤ 0
+        return ball, sizes[2:end]
+    else
+        ball = union!(ball, [center * s for s in S])
+        push!(sizes, length(ball))
+        if radius == 1
+            return ball, sizes[2:end]
+        else
+            for _ in 2:radius
+                new = collect(
+                    op(o, s) for o in @view(ball[sizes[end-1]:end]) for s in S
+                )
+                append!(ball, new)
+                unique!(ball)
+                push!(sizes, length(ball))
+            end
         end
-        push!(sizes, length(old))
+        return ball, sizes[2:end]
     end
-    return old, sizes[2:end]
+    # return wlmetric_ball_serial(S, center; radius = radius, op = op)
 end