java中的快速正弦和余弦函数 [英] Fast sine and cosine function in java

问题描述

我知道 Math.sin（）和 Math.cos（）函数，但我是我想知道是否有一种方法可以创建（或使用已经存在的）更快的功能，因为我不关心精确定位。我正在寻求执行基本的sin或cos计算，并使其基本上尽可能快地执行。只需迭代sigma几次比 Math.sin（）？

I know about the Math.sin() and Math.cos() functions, but I'm wondering if there's a way I can create (or use an already-existing) a faster function, given that I don't care about pinpoint accuracy. I'm looking to execute a basic sin or cos calculation, and have it perform essentially as fast as possible. Would simply iterating the sigma a few times be any faster than Math.sin()?

推荐答案

由于你不太关心准确性将它存储在预计算或只计算一次的表中，这就是我想要避免调用 Math 很多时候很贵。

Since you don't care much about accuracy store it in a table that is precomputed or only computed once, this is what I do when I want to avoid calls to Math which can be expensive when done alot.

大致

public class CosSineTable {
double[] cos = new double[361];
double[] sin = new double[361];
private static CosSineTable table = new CosSineTable();

private CosSineTable() {
    for (int i = 0; i <= 360; i++) {
        cos[i] = Math.cos(Math.toRadians(i));
        sin[i] = Math.sin(Math.toRadians(i));
    }
}

public double getSine(int angle) {
    int angleCircle = angle % 360;
    return sin[angleCircle];
}

public double getCos(int angle) {
    int angleCircle = angle % 360;
    return cos[angleCircle];
}

public static CosSineTable getTable() {
    return table;
}
}

我将循环优化和方法留给你。

I leave the optimization of the loop and methods to you.

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