何时在 JavaScript 中使用 Float32Array 而不是 Array [英] When to use Float32Array instead of Array in JavaScript

问题描述

什么时候对浏览器应用程序使用 Float32Array 而不是标准的 JavaScript Array 有意义?

When does it make sense to use a Float32Array instead of a standard JavaScript Array for browser applications?

这个性能测试显示Float32Array在一般，较慢 - 如果我理解正确的话，标准 Array 将数字存储为 64 位 - 所以在精度上没有优势.

This performance test shows Float32Array to be, in general, slower - and if I understand correctly a standard Array stores numbers as 64bit - so there is no advantage in precision.

除了任何可能的性能损失之外，Float32Array 还具有可读性的缺点 - 必须使用构造函数:

Aside from any possible performance hit, Float32Array also has the disadvantage of readability - having to use a constructor:

a = new Float32Array(2);
a[0] = 3.5;
a[1] = 4.5;

改为数组字面量

a = [3.5, 4.5];

我之所以这么问是因为我正在使用默认为 Float32Array 的库 glMatrix - 并且想知道是否有任何理由我不应该强迫它使用 Array相反，这将允许我使用数组文字.

I'm asking this because I'm using the library glMatrix which defaults to Float32Array - and wondering if there's any reason I shouldn't force it to use Array instead which will allow me to use array literals.

推荐答案

我给 glMatrix 的开发人员发了电子邮件，下面的回答包括他的评论(第 2 点和第 3 点):

I emailed the developer of glMatrix and my answer below includes his comments (points 2 & 3):

1. 使用 Array 创建新对象通常比使用 Float32Array 更快.小阵列的增益很显着，但大阵列的增益较小(取决于环境).

1. Creating a new object is generally quicker with Array than Float32Array. The gain is significant for small arrays, but is less (environment dependent) with larger arrays.

从TypedArray(例如Float32Array)访问数据通常比从普通数组更快，这意味着大多数使用 TypedArrays 的数组操作(除了创建新对象)更快.

Accessing data from a TypedArray (eg. Float32Array) is often faster than from a normal array, which means that most array operations (aside from creating a new object) are faster with TypedArrays.

正如@emidander 所述，glMatrix 主要是为 WebGL 开发的，它要求向量和矩阵作为 Float32Array 传递.因此，对于 WebGL 应用程序，任何性能测量都需要包含从 Array 到 Float32Array 的潜在成本高昂的转换.

As also stated by @emidander, glMatrix was developed primarily for WebGL, which requires that vectors and matrices be passed as Float32Array. So, for a WebGL application, the potentially costly conversion from Array to Float32Array would need to be included in any performance measurement.

因此，毫不奇怪，最佳选择取决于应用程序:

So, not surprisingly, the best choice is application dependent:

• 如果数组通常很小，和/或对它们的操作次数很少，以至于构造函数时间占数组生命周期的很大一部分，请使用Array.

如果代码可读性和性能一样重要，那么使用 Array(即使用 []，而不是构造函数).

If code readability is as important as performance, then use Array (i.e. use [], instead of a constructor).

如果数组非常大和/或用于许多操作，则使用 TypedArray.

If arrays are very large and/or are used for many operations, then use a TypedArray.

对于 WebGL 应用程序(或其他需要类型转换的应用程序)，使用 Float32Array(或其他 TypedArray).

For WebGL applications (or other applications that would otherwise require a type conversion), use Float32Array (or other TypedArray).

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