epsilon.java~1~

来自「一个一元曲线多项式数值演示例子」· JAVA~1~ 代码 · 共 37 行

package numbercruncher.mathutils;

/**
 * Compute the machine epsilon for the float and double types,
 * the largest positive floating-point value that, when added to 1,
 * results in a value equal to 1 due to roundoff.
 */
public final class Epsilon
{
    private static final float  floatEpsilon;
    private static final double doubleEpsilon;

    static {

        // Loop to compute the float epsilon value.
        float fTemp = 0.5f;
        while (1 + fTemp > 1) fTemp /= 2;
        floatEpsilon = fTemp;

        // Loop to compute the double epsilon value.
        double dTemp = 0.5;
        while (1 + dTemp > 1) dTemp /= 2;
        doubleEpsilon = dTemp;
    };

    /**
     * Return the float epsilon value.
     * @returns the value
     */
    public static float floatValue() { return floatEpsilon; }

    /**
     * Return the double epsilon value.
     * @returns the value
     */
    public static double doubleValue() { return doubleEpsilon; }
}