SpeedUpTheCodeSin.java

import java.util.Arrays;

public class SpeedUpTheCodeSin {

    public static void main(String[] args) {
        int N = 5;
        int terms = 5;
        float[] x = {0.5f, 1.0f, 1.5f, 2.0f, 2.5f};
        float[] result = new float[N];

        var denomCache = new int[terms + 1];
        denomCache[0] = 6;
        for (int j = 1; j <= terms; j++) {
            denomCache[j] = denomCache[j - 1] * (2 * j + 2) * (2 * j + 3);
        }

        var denoms = new float[terms + 1];
        for (int j = 0; j <= terms; j++) {
            denoms[j] = (float) 1 / denomCache[j];
        }

        sinxFast(N, terms, denoms, x, result);
        System.out.println(Arrays.toString(result));
    }

    static void sinxFast2(int N, int terms, float[] denoms, float[] x, float[] result) {
        float v, n1, n2;
        for (int i = 0; i < N; i++) {
            v = x[i];
            n1 = v * v;
            n2 = v * n1;
            for (int j = 1; j <= terms; j++) {
                n2 = -n2;
                v += n2 * denoms[j - 1];
                n2 *= n1;
            }
            result[i] = v;
        }
    }
}