Prefer arrow functions (#2344)

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Lipis 2020-11-06 22:06:39 +02:00 committed by GitHub
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19 changed files with 304 additions and 336 deletions

277
src/ga.ts
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@ -22,22 +22,25 @@ export type Direction = NVector;
export type Line = NVector;
export type Transform = NVector;
export function point(x: number, y: number): Point {
return [0, 0, 0, 0, y, x, 1, 0];
}
export const point = (x: number, y: number): Point => [0, 0, 0, 0, y, x, 1, 0];
export function origin(): Point {
return [0, 0, 0, 0, 0, 0, 1, 0];
}
export const origin = (): Point => [0, 0, 0, 0, 0, 0, 1, 0];
export function direction(x: number, y: number): Direction {
export const direction = (x: number, y: number): Direction => {
const norm = Math.hypot(x, y); // same as `inorm(direction(x, y))`
return [0, 0, 0, 0, y / norm, x / norm, 0, 0];
}
};
export function offset(x: number, y: number): Direction {
return [0, 0, 0, 0, y, x, 0, 0];
}
export const offset = (x: number, y: number): Direction => [
0,
0,
0,
0,
y,
x,
0,
0,
];
/// This is the "implementation" part of the library
@ -56,7 +59,7 @@ type NVector = readonly [
const NVECTOR_BASE = ["1", "e0", "e1", "e2", "e01", "e20", "e12", "e012"];
// Used to represent points, lines and transformations
export function nvector(value: number = 0, index: number = 0): NVector {
export const nvector = (value: number = 0, index: number = 0): NVector => {
const result = [0, 0, 0, 0, 0, 0, 0, 0];
if (index < 0 || index > 7) {
throw new Error(`Expected \`index\` betwen 0 and 7, got \`${index}\``);
@ -65,10 +68,10 @@ export function nvector(value: number = 0, index: number = 0): NVector {
result[index] = value;
}
return (result as unknown) as NVector;
}
};
const STRING_EPSILON = 0.000001;
export function toString(nvector: NVector): string {
export const toString = (nvector: NVector): string => {
const result = nvector
.map((value, index) =>
Math.abs(value) > STRING_EPSILON
@ -79,66 +82,58 @@ export function toString(nvector: NVector): string {
.filter((representation) => representation != null)
.join(" + ");
return result === "" ? "0" : result;
}
};
// Reverse the order of the basis blades.
export function reverse(nvector: NVector): NVector {
return [
nvector[0],
nvector[1],
nvector[2],
nvector[3],
-nvector[4],
-nvector[5],
-nvector[6],
-nvector[7],
];
}
export const reverse = (nvector: NVector): NVector => [
nvector[0],
nvector[1],
nvector[2],
nvector[3],
-nvector[4],
-nvector[5],
-nvector[6],
-nvector[7],
];
// Poincare duality operator.
export function dual(nvector: NVector): NVector {
return [
nvector[7],
nvector[6],
nvector[5],
nvector[4],
nvector[3],
nvector[2],
nvector[1],
nvector[0],
];
}
export const dual = (nvector: NVector): NVector => [
nvector[7],
nvector[6],
nvector[5],
nvector[4],
nvector[3],
nvector[2],
nvector[1],
nvector[0],
];
// Clifford Conjugation
export function conjugate(nvector: NVector): NVector {
return [
nvector[0],
-nvector[1],
-nvector[2],
-nvector[3],
-nvector[4],
-nvector[5],
-nvector[6],
nvector[7],
];
}
export const conjugate = (nvector: NVector): NVector => [
nvector[0],
-nvector[1],
-nvector[2],
-nvector[3],
-nvector[4],
-nvector[5],
-nvector[6],
nvector[7],
];
// Main involution
export function involute(nvector: NVector): NVector {
return [
nvector[0],
-nvector[1],
-nvector[2],
-nvector[3],
nvector[4],
nvector[5],
nvector[6],
-nvector[7],
];
}
export const involute = (nvector: NVector): NVector => [
nvector[0],
-nvector[1],
-nvector[2],
-nvector[3],
nvector[4],
nvector[5],
nvector[6],
-nvector[7],
];
// Multivector addition
export function add(a: NVector, b: NVector | number): NVector {
export const add = (a: NVector, b: NVector | number): NVector => {
if (isNumber(b)) {
return [a[0] + b, a[1], a[2], a[3], a[4], a[5], a[6], a[7]];
}
@ -152,10 +147,10 @@ export function add(a: NVector, b: NVector | number): NVector {
a[6] + b[6],
a[7] + b[7],
];
}
};
// Multivector subtraction
export function sub(a: NVector, b: NVector | number): NVector {
export const sub = (a: NVector, b: NVector | number): NVector => {
if (isNumber(b)) {
return [a[0] - b, a[1], a[2], a[3], a[4], a[5], a[6], a[7]];
}
@ -169,10 +164,10 @@ export function sub(a: NVector, b: NVector | number): NVector {
a[6] - b[6],
a[7] - b[7],
];
}
};
// The geometric product.
export function mul(a: NVector, b: NVector | number): NVector {
export const mul = (a: NVector, b: NVector | number): NVector => {
if (isNumber(b)) {
return [
a[0] * b,
@ -223,112 +218,94 @@ export function mul(a: NVector, b: NVector | number): NVector {
b[1] * a[6] +
b[0] * a[7],
];
}
};
export function mulScalar(a: NVector, b: NVector): number {
return b[0] * a[0] + b[2] * a[2] + b[3] * a[3] - b[6] * a[6];
}
export const mulScalar = (a: NVector, b: NVector): number =>
b[0] * a[0] + b[2] * a[2] + b[3] * a[3] - b[6] * a[6];
// The outer/exterior/wedge product.
export function meet(a: NVector, b: NVector): NVector {
return [
b[0] * a[0],
b[1] * a[0] + b[0] * a[1],
b[2] * a[0] + b[0] * a[2],
b[3] * a[0] + b[0] * a[3],
b[4] * a[0] + b[2] * a[1] - b[1] * a[2] + b[0] * a[4],
b[5] * a[0] - b[3] * a[1] + b[1] * a[3] + b[0] * a[5],
b[6] * a[0] + b[3] * a[2] - b[2] * a[3] + b[0] * a[6],
b[7] * a[0] +
b[6] * a[1] +
b[5] * a[2] +
b[4] * a[3] +
b[3] * a[4] +
b[2] * a[5] +
b[1] * a[6],
];
}
export const meet = (a: NVector, b: NVector): NVector => [
b[0] * a[0],
b[1] * a[0] + b[0] * a[1],
b[2] * a[0] + b[0] * a[2],
b[3] * a[0] + b[0] * a[3],
b[4] * a[0] + b[2] * a[1] - b[1] * a[2] + b[0] * a[4],
b[5] * a[0] - b[3] * a[1] + b[1] * a[3] + b[0] * a[5],
b[6] * a[0] + b[3] * a[2] - b[2] * a[3] + b[0] * a[6],
b[7] * a[0] +
b[6] * a[1] +
b[5] * a[2] +
b[4] * a[3] +
b[3] * a[4] +
b[2] * a[5] +
b[1] * a[6],
];
// The regressive product.
export function join(a: NVector, b: NVector): NVector {
return [
joinScalar(a, b),
a[1] * b[7] + a[4] * b[5] - a[5] * b[4] + a[7] * b[1],
a[2] * b[7] - a[4] * b[6] + a[6] * b[4] + a[7] * b[2],
a[3] * b[7] + a[5] * b[6] - a[6] * b[5] + a[7] * b[3],
a[4] * b[7] + a[7] * b[4],
a[5] * b[7] + a[7] * b[5],
a[6] * b[7] + a[7] * b[6],
a[7] * b[7],
];
}
export const join = (a: NVector, b: NVector): NVector => [
joinScalar(a, b),
a[1] * b[7] + a[4] * b[5] - a[5] * b[4] + a[7] * b[1],
a[2] * b[7] - a[4] * b[6] + a[6] * b[4] + a[7] * b[2],
a[3] * b[7] + a[5] * b[6] - a[6] * b[5] + a[7] * b[3],
a[4] * b[7] + a[7] * b[4],
a[5] * b[7] + a[7] * b[5],
a[6] * b[7] + a[7] * b[6],
a[7] * b[7],
];
export function joinScalar(a: NVector, b: NVector): number {
return (
a[0] * b[7] +
a[1] * b[6] +
a[2] * b[5] +
a[3] * b[4] +
a[4] * b[3] +
a[5] * b[2] +
a[6] * b[1] +
a[7] * b[0]
);
}
export const joinScalar = (a: NVector, b: NVector): number =>
a[0] * b[7] +
a[1] * b[6] +
a[2] * b[5] +
a[3] * b[4] +
a[4] * b[3] +
a[5] * b[2] +
a[6] * b[1] +
a[7] * b[0];
// The inner product.
export function dot(a: NVector, b: NVector): NVector {
return [
b[0] * a[0] + b[2] * a[2] + b[3] * a[3] - b[6] * a[6],
b[1] * a[0] +
b[0] * a[1] -
b[4] * a[2] +
b[5] * a[3] +
b[2] * a[4] -
b[3] * a[5] -
b[7] * a[6] -
b[6] * a[7],
b[2] * a[0] + b[0] * a[2] - b[6] * a[3] + b[3] * a[6],
b[3] * a[0] + b[6] * a[2] + b[0] * a[3] - b[2] * a[6],
b[4] * a[0] + b[7] * a[3] + b[0] * a[4] + b[3] * a[7],
b[5] * a[0] + b[7] * a[2] + b[0] * a[5] + b[2] * a[7],
b[6] * a[0] + b[0] * a[6],
b[7] * a[0] + b[0] * a[7],
];
}
export const dot = (a: NVector, b: NVector): NVector => [
b[0] * a[0] + b[2] * a[2] + b[3] * a[3] - b[6] * a[6],
b[1] * a[0] +
b[0] * a[1] -
b[4] * a[2] +
b[5] * a[3] +
b[2] * a[4] -
b[3] * a[5] -
b[7] * a[6] -
b[6] * a[7],
b[2] * a[0] + b[0] * a[2] - b[6] * a[3] + b[3] * a[6],
b[3] * a[0] + b[6] * a[2] + b[0] * a[3] - b[2] * a[6],
b[4] * a[0] + b[7] * a[3] + b[0] * a[4] + b[3] * a[7],
b[5] * a[0] + b[7] * a[2] + b[0] * a[5] + b[2] * a[7],
b[6] * a[0] + b[0] * a[6],
b[7] * a[0] + b[0] * a[7],
];
export function norm(a: NVector): number {
return Math.sqrt(
Math.abs(a[0] * a[0] - a[2] * a[2] - a[3] * a[3] + a[6] * a[6]),
);
}
export const norm = (a: NVector): number =>
Math.sqrt(Math.abs(a[0] * a[0] - a[2] * a[2] - a[3] * a[3] + a[6] * a[6]));
export function inorm(a: NVector): number {
return Math.sqrt(
Math.abs(a[7] * a[7] - a[5] * a[5] - a[4] * a[4] + a[1] * a[1]),
);
}
export const inorm = (a: NVector): number =>
Math.sqrt(Math.abs(a[7] * a[7] - a[5] * a[5] - a[4] * a[4] + a[1] * a[1]));
export function normalized(a: NVector): NVector {
export const normalized = (a: NVector): NVector => {
const n = norm(a);
if (n === 0 || n === 1) {
return a;
}
const sign = a[6] < 0 ? -1 : 1;
return mul(a, sign / n);
}
};
export function inormalized(a: NVector): NVector {
export const inormalized = (a: NVector): NVector => {
const n = inorm(a);
if (n === 0 || n === 1) {
return a;
}
return mul(a, 1 / n);
}
};
function isNumber(a: any): a is number {
return typeof a === "number";
}
const isNumber = (a: any): a is number => typeof a === "number";
export const E0: NVector = nvector(1, 1);
export const E1: NVector = nvector(1, 2);