Make prime 13 a little longer in 3D WGP

ref #18

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.
 

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', () => {

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.