This *really* seems like a good use case for WASM + SIMD (and a small static heap), given the number-heavy nature of it.
On Mon, Jun 5, 2017, 10:47 kdex <[email protected]> wrote: > Thanks for the pointers! > > > `array.reduce( (a,b)=>a+b )` (Although I wouldn't object to `Math.sum()`) > Yes; no objections here. > > > `Math.hypot(...array)` > I'm aware of `Math.hypot`, but it only covers `p = 2`. The important thing > about `Math.hypot` is that it doesn't demolish numbers with high > magnitudes in > the process of raising them to the power of two. > > It would be great to have the same safety for other cases (i.e. `p = 3`) as > well. The idea was to generalize the concept for every `p`. > > > Will DOMPoint solve your use cases? (Personal annoyance: you can't index > > DOMPoint numerically.) > > Unfortunately, `DOMPoint` would be a Web API, which might (and probably > will) > not be available in other environments. > > Essentially, what I'm suggesting is an environment-indepdendent `Vector` > class, though I'm reluctant to go into more detail, as I feel that hardly > anyone would want a `Vector` without proper operator overloading. > > On Monday, June 5, 2017 1:09:21 PM CEST peter miller wrote: > > Hi, > > > > > In mathematics, the p-norm of a vector is defined as in [1]. > > > > > > For p = 1, we get the taxicab norm, > > > > `array.reduce( (a,b)=>a+b )` (Although I wouldn't object to `Math.sum()`) > > > > > for p = 2 we get the Euclidean norm, > > > > `Math.hypot(...array)` > > > > > and > > > for the limit as p → ±∞ we get the maximum/minimum norm. > > > > `Math.max(...array)` > > > > > Particularly the Euclidean norm is pretty common in graphics-related > > > code. > > > > > > This could be implemented as an addition to`TypedArray.prototype`. > > > > > > A rough sketch might look like so: > > > > > > ```js > > > TypedArray.prototype.norm = function(p) { > > > > > > if (Number.isNaN(p)) { > > > > > > return p; > > > > > > } > > > const { abs, min, max, sign } = Math; > > > if (Number.isFinite(p)) { > > > > > > return this.map(x => abs(x) ** p).reduce((a, b) => a + b, > 0) ** (1 / > > > > > > p); > > > > > > } > > > return abs((sign(p) === 1 ? max : min)(...this)); > > > > > > }; > > > ``` > > > > > > Since norms are a little too specific for `Array` (as they don't > > > necessarily > > > contain numerical values), it might be worth pondering about a > > > native`Vector` > > > implementation. > > > > Will DOMPoint solve your use cases? (Personal annoyance: you can't index > > DOMPoint numerically.) > > > > > > Peter_______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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