本文整理汇总了Java中sun.misc.FpUtils.nextDown方法的典型用法代码示例。如果您正苦于以下问题：Java FpUtils.nextDown方法的具体用法？Java FpUtils.nextDown怎么用？Java FpUtils.nextDown使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类sun.misc.FpUtils的用法示例。
在下文中一共展示了FpUtils.nextDown方法的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: main
import sun.misc.FpUtils; //导入方法依赖的package包/类
public static void main(String args[]) {
int failures = 0;
double twoToThe52 = FpUtils.scalb(1.0, 52); // 2^52
double [][] testCases = {
{0.0, 0.0},
{Double.MIN_VALUE, 0.0},
{FpUtils.nextDown(DoubleConsts.MIN_NORMAL), 0.0},
{DoubleConsts.MIN_NORMAL, 0.0},
{0.2, 0.0},
{FpUtils.nextDown(0.5), 0.0},
{ 0.5, 0.0},
{ FpUtils.nextUp(0.5), 1.0},
{0.7, 1.0},
{FpUtils.nextDown(1.0), 1.0},
{ 1.0, 1.0},
{ FpUtils.nextUp(1.0), 1.0},
{FpUtils.nextDown(1.5), 1.0},
{ 1.5, 2.0},
{ FpUtils.nextUp(1.5), 2.0},
{4.2, 4.0},
{4.5, 4.0},
{4.7, 5.0},
{7.5, 8.0},
{7.2, 7.0},
{7.7, 8.0},
{150000.75, 150001.0},
{300000.5, 300000.0},
{FpUtils.nextUp(300000.5), 300001.0},
{FpUtils.nextDown(300000.75), 300001.0},
{300000.75, 300001.0},
{FpUtils.nextUp(300000.75), 300001.0},
{300000.99, 300001.0},
{262144.75, 262145.0}, //(2^18 ) + 0.75
{499998.75, 499999.0},
{524287.75, 524288.0}, //(2^19 -1) + 0.75
{524288.75, 524289.0},
{FpUtils.nextDown(twoToThe52), twoToThe52},
{twoToThe52, twoToThe52},
{FpUtils.nextUp(twoToThe52), FpUtils.nextUp(twoToThe52)},
{Double.MAX_VALUE, Double.MAX_VALUE},
{Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY},
{Double.NaN, Double.NaN}
};
for(int i = 0; i < testCases.length; i++) {
failures += testRintCase(testCases[i][0], testCases[i][1]);
}
// Test values throughout exponent range
for(double d = Double.MIN_VALUE;
d < Double.POSITIVE_INFINITY; d *= 2) {
failures += testRintCase(d, ((d<=0.5)?0.0:d));
}
if (failures > 0) {
System.err.println("Testing {Math, StrictMath}.rint incurred "
+ failures + " failures.");
throw new RuntimeException();
}
}
示例2: significandAlignmentTests
import sun.misc.FpUtils; //导入方法依赖的package包/类
static int significandAlignmentTests() {
int failures = 0;
// baseSignif * 2^baseExp = nextDown(2.0)
long [] baseSignifs = {
0x1ffffffffffffe00L,
0x1fffffffffffff00L
};
double [] answers = {
FpUtils.nextDown(FpUtils.nextDown(2.0)),
FpUtils.nextDown(2.0),
2.0
};
int baseExp = -60;
int count = 0;
for(int i = 0; i < 2; i++) {
for(long j = 0; j <= 0xfL; j++) {
for(long k = 0; k <= 8; k+= 4) { // k = {0, 4, 8}
long base = baseSignifs[i];
long testValue = base | (j<<4) | k;
int offset = 0;
// Calculate when significand should be incremented
// see table 4.7 in Koren book
if ((base & 0x100L) == 0L ) { // lsb is 0
if ( (j >= 8L) && // round is 1
((j & 0x7L) != 0 || k != 0 ) ) // sticky is 1
offset = 1;
}
else { // lsb is 1
if (j >= 8L) // round is 1
offset = 1;
}
double expected = answers[i+offset];
for(int m = -2; m <= 3; m++) {
count ++;
// Form equal value string and evaluate it
String s = "0x" +
Long.toHexString((m >=0) ?(testValue<<m):(testValue>>(-m))) +
"p" + (baseExp - m);
failures += testCase(s, expected);
}
}
}
}
return failures;
}