From a41bf23bbf5eb45f9880a38d18ab650050ebbad2 Mon Sep 17 00:00:00 2001
From: Lumi Pakkanen <lumi.pakkanen@gmail.com>
Date: Mon, 10 Jun 2024 12:04:51 +0300
Subject: [PATCH] Make prime 13 a little longer in 3D WGP

ref #18
---
 CHANGELOG.md                     | 4 ++++
 src/__tests__/lattice-3d.spec.ts | 6 ++++++
 src/lattice-3d.ts                | 2 +-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5e31cae..63f1ac7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Change log
 
+## 0.2.0
+ * Tweak: The coordinate for prime 13 in 3D `WGP()` is a little longer. [#18](https://github.com/xenharmonic-devs/ji-lattice/issues/18)
+ * Redesign: Presets like `scottDakota24()` now work with default order of prime numbers. [#19](https://github.com/xenharmonic-devs/ji-lattice/issues/19)
+
 ## 0.1.0
  * Feature: 3-dimensional prime lattices.
 
diff --git a/src/__tests__/lattice-3d.spec.ts b/src/__tests__/lattice-3d.spec.ts
index f153cf2..3123791 100644
--- a/src/__tests__/lattice-3d.spec.ts
+++ b/src/__tests__/lattice-3d.spec.ts
@@ -39,6 +39,12 @@ describe('Wilson-Grady-Pakkanen lattice', () => {
       {x1: 80, y1: 0, z1: 0, x2: 80, y2: 0, z2: 40, type: 'primary'}, // 9 -> 63
     ]);
   });
+
+  it('has a short but not too short vector associated with prime 13', () => {
+    const thirteen = toMonzo(13);
+    const {vertices} = spanLattice3D([thirteen], WGP9());
+    expect(vertices).toEqual([{index: 0, x: -8, y: -4, z: 7}]);
+  });
 });
 
 describe('Prime sphere coordinates', () => {
diff --git a/src/lattice-3d.ts b/src/lattice-3d.ts
index 4f9c9f1..8930dfe 100644
--- a/src/lattice-3d.ts
+++ b/src/lattice-3d.ts
@@ -64,7 +64,7 @@ const WGP_X = [23, 40, 0, 0, -14, -8, -5, 0, 20];
 // Y-coordinates for every prime up to 23.
 const WGP_Y = [-45, 0, -40, 0, -18, -4, -32, -25, -3];
 // Z-coordinates for every prime up to 23.
-const WGP_Z = [19, 0, 0, 40, 13, 2, 5, 9, 15];
+const WGP_Z = [19, 0, 0, 40, 13, 7, 5, 9, 15];
 
 /**
  * Combine edges that share an endpoint and slope into longer ones.