From 2a4eb25fefeabb2d615694a32064a6e4b85749f4 Mon Sep 17 00:00:00 2001
From: Marshall Lochbaum <mwlochbaum@gmail.com>
Date: Thu, 20 May 2021 13:20:01 -0400
Subject: =?UTF-8?q?Lower-level=20implementation=20for=20/=E2=81=BC=20check?=
 =?UTF-8?q?ing?=
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---
 src/r1.bqn | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/r1.bqn b/src/r1.bqn
index 58f40c5d..f925b06d 100644
--- a/src/r1.bqn
+++ b/src/r1.bqn
@@ -207,6 +207,12 @@ Indices←{
   "/𝕩: 𝕩 must consist of natural numbers" ! 1×´Nat⌜𝕩
   Ind 𝕩
 }
+IndicesInv←{
+  IA 1==𝕩
+  IA 1×´Nat⌜𝕩
+  IX (0⊸≤)◶⟨1,1×´(⊢≤○(⊑⟜𝕩)1⊸+)⌜∘↕⟩-˜≠𝕩
+  GroupLen 𝕩
+}
 SelfClas ← (PermInv∘⍋∘Rep˜⊏˜¯1+`⊢) _self
 OccurrenceCount ← ↕∘≠⊸(⊣-¨·⌈`ר) _self
 
@@ -823,7 +829,7 @@ PrimInverse ← INF _lookup_ ⟨
   '↕', ≢_invChk_↕ ⊘ (IA∘0)  # Should trace edge and invChk
   '⌽', ⌽ ⊘ (-⊸⌽)
   '⍉', TransposeInv ⊘ ReorderAxesInv
-  '/', {IA 1==𝕩⋄IA 1∧´Nat⌜𝕩⋄IX(1∧´¯1⊸↓≤1⊸↓)𝕩⋄GroupLen𝕩}⊘(IA∘0)
+  '/', IndicesInv ⊘ (IA∘0)
   '⊔', GroupIndsInv ⊘ GroupInv
 ⟩
 SwapInverse ← INF _lookup_ ⟨
-- 
cgit v1.2.3