From 52f8a6655c65584cf0740021dcd6fed428fc9b6c Mon Sep 17 00:00:00 2001
From: Marshall Lochbaum <mwlochbaum@gmail.com>
Date: Tue, 8 Sep 2020 23:44:03 -0400
Subject: Faster high-rank Join implementation

---
 dzref | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

(limited to 'dzref')

diff --git a/dzref b/dzref
index 0d070602..6fcc5f5f 100755
--- a/dzref
+++ b/dzref
@@ -38,17 +38,22 @@ Windows←{
 # LAYER 6: Everything else
 
 
-Join←{
-  C←(<⟨⟩)⥊⊸∾⌜´⊢  # Cartesian array product
+Join←(1≠=)◶⟨∨´1≠=⌜,1⟩◶{
+  # List of lists
+  i←j←¯1 ⋄ e←⟨⟩ ⋄ a←𝕩
+  {{e↩a⊑˜i↩𝕩⋄j↩¯1}⍟(i⊸≠)𝕩⋄(j↩j+1)⊑e}⌜/≠⌜𝕩
+}‿{
+  # Multidimensional
   ! IsArray 𝕩
-  s←≢¨𝕩
-  d←≠⊑s
-  ! ∧´⥊d=≠¨s
+  n←≠z←⥊𝕩 ⋄ s←≢⌜z ⋄ d←≠0⊑s
+  ! ∧´d=≠⌜s
   ! d≥=𝕩
-  l←(≢𝕩){(𝕩⊑⟜≢a⊑˜(j=𝕩)⊸×)¨↕𝕨}¨j←↕r←=a←𝕩
-  ! (r↑¨s)≡C l
-  i←C{p←+´¨↑𝕩⋄(↕⊑⌽p)-𝕩/¯1↓p}¨l
-  >i<¨⊸⊏¨l/𝕩
+  q←1 ⋄ l←(≢𝕩){m←𝕩⊸⊑⌜s ⋄ r←⊑⟜m⌜q×↕𝕨 ⋄ !m≡n⥊r⊣⌜↕q ⋄ q×↩𝕨 ⋄ r}¨○⌽↕=𝕩
+  t←(=𝕩)↓0⊑s
+  ! ∧´(t≡(=𝕩)⊸↓)⌜s
+  i←<0 ⋄ q↩<1
+  {s←0⋄p←{o←s⋄s+↩𝕩⋄o}⌜𝕩 ⋄ j←↕s ⋄ i↩(j⊢⌜i)+(j-𝕩/p)×⌜q ⋄ q×⌜˜↩𝕩/𝕩}⌜l
+  i(0<≠t)◶⟨⊑⟜⥊¨,{ti←t⥊↕tp←×´t⋄((tp×𝕨)+⌜ti)⊑⟜⥊¨𝕩⊣⌜ti}⟩(⌽l)/𝕩
 }⍟(0<≠∘⥊)
 
 ∾ ↩ Join           ⊘ ∾
-- 
cgit v1.2.3