/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.lang;
/**
* Class Math provides basic math constants and operations such as trigonometric
* functions, hyperbolic functions, exponential, logarithms, etc.
*
* @since Android 1.0
*/
public final class Math {
/**
* The double value closest to e, the base of the natural logarithm.
*
* @since Android 1.0
*/
public static final double E = 2.718281828459045;
/**
* The double value closest to pi, the ratio of a circle's circumference to
* its diameter.
*
* @since Android 1.0
*/
public static final double PI = 3.141592653589793;
private static java.util.Random random;
/**
* Prevents this class from being instantiated.
*/
private Math() {
}
/**
* Returns the absolute value of the argument.
* <p>
* Special cases:
* <ul>
* <li>{@code abs(-0.0) = +0.0}</li>
* <li>{@code abs(+infinity) = +infinity}</li>
* <li>{@code abs(-infinity) = +infinity}</li>
* <li>{@code abs(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose absolute value has to be computed.
* @return the absolute value of the argument.
* @since Android 1.0
*/
public static double abs(double d) {
long bits = Double.doubleToLongBits(d);
bits &= 0x7fffffffffffffffL;
return Double.longBitsToDouble(bits);
}
/**
* Returns the absolute value of the argument.
* <p>
* Special cases:
* <ul>
* <li>{@code abs(-0.0) = +0.0}</li>
* <li>{@code abs(+infinity) = +infinity}</li>
* <li>{@code abs(-infinity) = +infinity}</li>
* <li>{@code abs(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param f
* the value whose absolute value has to be computed.
* @return the argument if it is positive, otherwise the negation of the
* argument.
* @since Android 1.0
*/
public static float abs(float f) {
int bits = Float.floatToIntBits(f);
bits &= 0x7fffffff;
return Float.intBitsToFloat(bits);
}
/**
* Returns the absolute value of the argument.
* <p>
* If the argument is {@code Integer.MIN_VALUE}, {@code Integer.MIN_VALUE}
* is returned.
* </p>
*
* @param i
* the value whose absolute value has to be computed.
* @return the argument if it is positive, otherwise the negation of the
* argument.
* @since Android 1.0
*/
public static int abs(int i) {
return i >= 0 ? i : -i;
}
/**
* Returns the absolute value of the argument. If the argument is {@code
* Long.MIN_VALUE}, {@code Long.MIN_VALUE} is returned.
*
* @param l
* the value whose absolute value has to be computed.
* @return the argument if it is positive, otherwise the negation of the
* argument.
* @since Android 1.0
*/
public static long abs(long l) {
return l >= 0 ? l : -l;
}
/**
* Returns the closest double approximation of the arc cosine of the
* argument within the range {@code [0..pi]}. The returned result is within
* 1 ulp (unit in the last place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code acos((anything > 1) = NaN}</li>
* <li>{@code acos((anything < -1) = NaN}</li>
* <li>{@code acos(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value to compute arc cosine of.
* @return the arc cosine of the argument.
* @since Android 1.0
*/
public static native double acos(double d);
/**
* Returns the closest double approximation of the arc sine of the argument
* within the range {@code [-pi/2..pi/2]}. The returned result is within 1
* ulp (unit in the last place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code asin((anything > 1)) = NaN}</li>
* <li>{@code asin((anything < -1)) = NaN}</li>
* <li>{@code asin(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose arc sine has to be computed.
* @return the arc sine of the argument.
* @since Android 1.0
*/
public static native double asin(double d);
/**
* Returns the closest double approximation of the arc tangent of the
* argument within the range {@code [-pi/2..pi/2]}. The returned result is
* within 1 ulp (unit in the last place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code atan(+0.0) = +0.0}</li>
* <li>{@code atan(-0.0) = -0.0}</li>
* <li>{@code atan(+infinity) = +pi/2}</li>
* <li>{@code atan(-infinity) = -pi/2}</li>
* <li>{@code atan(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose arc tangent has to be computed.
* @return the arc tangent of the argument.
* @since Android 1.0
*/
public static native double atan(double d);
/**
* Returns the closest double approximation of the arc tangent of
* {@code y/x} within the range {@code [-pi..pi]}. This is the angle of the
* polar representation of the rectangular coordinates (x,y). The returned
* result is within 2 ulps (units in the last place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code atan2((anything), NaN ) = NaN;}</li>
* <li>{@code atan2(NaN , (anything) ) = NaN;}</li>
* <li>{@code atan2(+0.0, +(anything but NaN)) = +0.0}</li>
* <li>{@code atan2(-0.0, +(anything but NaN)) = -0.0}</li>
* <li>{@code atan2(+0.0, -(anything but NaN)) = +pi}</li>
* <li>{@code atan2(-0.0, -(anything but NaN)) = -pi}</li>
* <li>{@code atan2(+(anything but 0 and NaN), 0) = +pi/2}</li>
* <li>{@code atan2(-(anything but 0 and NaN), 0) = -pi/2}</li>
* <li>{@code atan2(+(anything but infinity and NaN), +infinity)} {@code =}
* {@code +0.0}</li>
* <li>{@code atan2(-(anything but infinity and NaN), +infinity)} {@code =}
* {@code -0.0}</li>
* <li>{@code atan2(+(anything but infinity and NaN), -infinity) = +pi}</li>
* <li>{@code atan2(-(anything but infinity and NaN), -infinity) = -pi}</li>
* <li>{@code atan2(+infinity, +infinity ) = +pi/4}</li>
* <li>{@code atan2(-infinity, +infinity ) = -pi/4}</li>
* <li>{@code atan2(+infinity, -infinity ) = +3pi/4}</li>
* <li>{@code atan2(-infinity, -infinity ) = -3pi/4}</li>
* <li>{@code atan2(+infinity, (anything but,0, NaN, and infinity))}
* {@code =} {@code +pi/2}</li>
* <li>{@code atan2(-infinity, (anything but,0, NaN, and infinity))}
* {@code =} {@code -pi/2}</li>
* </ul>
* </p>
*
* @param y
* the numerator of the value whose atan has to be computed.
* @param x
* the denominator of the value whose atan has to be computed.
* @return the arc tangent of {@code y/x}.
* @since Android 1.0
*/
public static native double atan2(double y, double x);
// BEGIN android-note
// parameter names changed from d1 / d2 to x / y
// END android-note
/**
* Returns the closest double approximation of the cube root of the
* argument.
* <p>
* Special cases:
* <ul>
* <li>{@code cbrt(+0.0) = +0.0}</li>
* <li>{@code cbrt(-0.0) = -0.0}</li>
* <li>{@code cbrt(+infinity) = +infinity}</li>
* <li>{@code cbrt(-infinity) = -infinity}</li>
* <li>{@code cbrt(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose cube root has to be computed.
* @return the cube root of the argument.
* @since Android 1.0
*/
public static native double cbrt(double d);
/**
* Returns the double conversion of the most negative (closest to
* negative infinity) integer value which is greater than the argument.
* <p>
* Special cases:
* <ul>
* <li>{@code ceil(+0.0) = +0.0}</li>
* <li>{@code ceil(-0.0) = -0.0}</li>
* <li>{@code ceil((anything in range (-1,0)) = -0.0}</li>
* <li>{@code ceil(+infinity) = +infinity}</li>
* <li>{@code ceil(-infinity) = -infinity}</li>
* <li>{@code ceil(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose closest integer value has to be computed.
* @return the ceiling of the argument.
* @since Android 1.0
*/
public static native double ceil(double d);
/**
* Returns the closest double approximation of the cosine of the argument.
* The returned result is within 1 ulp (unit in the last place) of the real
* result.
* <p>
* Special cases:
* <ul>
* <li>{@code cos(+infinity) = NaN}</li>
* <li>{@code cos(-infinity) = NaN}</li>
* <li>{@code cos(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the angle whose cosine has to be computed, in radians.
* @return the cosine of the argument.
* @since Android 1.0
*/
public static native double cos(double d);
/**
* Returns the closest double approximation of the hyperbolic cosine of the
* argument. The returned result is within 2.5 ulps (units in the last
* place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code cosh(+infinity) = +infinity}</li>
* <li>{@code cosh(-infinity) = +infinity}</li>
* <li>{@code cosh(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose hyperbolic cosine has to be computed.
* @return the hyperbolic cosine of the argument.
* @since Android 1.0
*/
public static native double cosh(double d);
/**
* Returns the closest double approximation of the raising "e" to the power
* of the argument. The returned result is within 1 ulp (unit in the last
* place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code exp(+infinity) = +infinity}</li>
* <li>{@code exp(-infinity) = +0.0}</li>
* <li>{@code exp(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose exponential has to be computed.
* @return the exponential of the argument.
* @since Android 1.0
*/
public static native double exp(double d);
/**
* Returns the closest double approximation of <i>{@code e}</i><sup>
* {@code d}</sup>{@code - 1}. If the argument is very close to 0, it is
* much more accurate to use {@code expm1(d)+1} than {@code exp(d)} (due to
* cancellation of significant digits). The returned result is within 1 ulp
* (unit in the last place) of the real result.
* <p>
* For any finite input, the result is not less than -1.0. If the real
* result is within 0.5 ulp of -1, -1.0 is returned.
* <p>
* Special cases:
* <ul>
* <li>{@code expm1(+0.0) = +0.0}</li>
* <li>{@code expm1(-0.0) = -0.0}</li>
* <li>{@code expm1(+infinity) = +infinity}</li>
* <li>{@code expm1(-infinity) = -1.0}</li>
* <li>{@code expm1(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value to compute the <i>{@code e}</i><sup>{@code d}
* </sup>{@code - 1} of.
* @return the <i>{@code e}</i><sup>{@code d}</sup>{@code - 1} value
* of the argument.
* @since Android 1.0
*/
public static native double expm1(double d);
/**
* Returns the double conversion of the most positive (closest to positive
* infinity) integer value which is less than the argument.
* <p>
* Special cases:
* <ul>
* <li>{@code floor(+0.0) = +0.0}</li>
* <li>{@code floor(-0.0) = -0.0}</li>
* <li>{@code floor(+infinity) = +infinity}</li>
* <li>{@code floor(-infinity) = -infinity}</li>
* <li>{@code floor(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose closest integer value has to be computed.
* @return the floor of the argument.
* @since Android 1.0
*/
public static native double floor(double d);
/**
* Returns {@code sqrt(}<i>{@code x}</i><sup>{@code 2}</sup>{@code +}
* <i> {@code y}</i><sup>{@code 2}</sup>{@code )}. The final result is
* without medium underflow or overflow. The returned result is within 1 ulp
* (unit in the last place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code hypot(+infinity, (anything including NaN)) = +infinity}</li>
* <li>{@code hypot(-infinity, (anything including NaN)) = +infinity}</li>
* <li>{@code hypot((anything including NaN), +infinity) = +infinity}</li>
* <li>{@code hypot((anything including NaN), -infinity) = +infinity}</li>
* <li>{@code hypot(NaN, NaN) = NaN}</li>
* </ul>
* </p>
*
* @param x
* a double number.
* @param y
* a double number.
* @return the {@code sqrt(}<i>{@code x}</i><sup>{@code 2}</sup>{@code +}
* <i> {@code y}</i><sup>{@code 2}</sup>{@code )} value of the
* arguments.
* @since Android 1.0
*/
public static native double hypot(double x, double y);
/**
* Returns the remainder of dividing {@code x} by {@code y} using the IEEE
* 754 rules. The result is {@code x-round(x/p)*p} where {@code round(x/p)}
* is the nearest integer (rounded to even), but without numerical
* cancellation problems.
* <p>
* Special cases:
* <ul>
* <li>{@code IEEEremainder((anything), 0) = NaN}</li>
* <li>{@code IEEEremainder(+infinity, (anything)) = NaN}</li>
* <li>{@code IEEEremainder(-infinity, (anything)) = NaN}</li>
* <li>{@code IEEEremainder(NaN, (anything)) = NaN}</li>
* <li>{@code IEEEremainder((anything), NaN) = NaN}</li>
* <li>{@code IEEEremainder(x, +infinity) = x } where x is anything but
* +/-infinity</li>
* <li>{@code IEEEremainder(x, -infinity) = x } where x is anything but
* +/-infinity</li>
* </ul>
* </p>
*
* @param x
* the numerator of the operation.
* @param y
* the denominator of the operation.
* @return the IEEE754 floating point reminder of of {@code x/y}.
* @since Android 1.0
*/
public static native double IEEEremainder(double x, double y);
// BEGIN android-note
// parameter names changed from d1 / d2 to x / y
// END android-note
/**
* Returns the closest double approximation of the natural logarithm of the
* argument. The returned result is within 1 ulp (unit in the last place) of
* the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code log(+0.0) = -infinity}</li>
* <li>{@code log(-0.0) = -infinity}</li>
* <li>{@code log((anything < 0) = NaN}</li>
* <li>{@code log(+infinity) = +infinity}</li>
* <li>{@code log(-infinity) = NaN}</li>
* <li>{@code log(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose log has to be computed.
* @return the natural logarithm of the argument.
* @since Android 1.0
*/
public static native double log(double d);
/**
* Returns the closest double approximation of the base 10 logarithm of the
* argument. The returned result is within 1 ulp (unit in the last place) of
* the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code log10(+0.0) = -infinity}</li>
* <li>{@code log10(-0.0) = -infinity}</li>
* <li>{@code log10((anything < 0) = NaN}</li>
* <li>{@code log10(+infinity) = +infinity}</li>
* <li>{@code log10(-infinity) = NaN}</li>
* <li>{@code log10(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose base 10 log has to be computed.
* @return the natural logarithm of the argument.
* @since Android 1.0
*/
public static native double log10(double d);
/**
* Returns the closest double approximation of the natural logarithm of the
* sum of the argument and 1. If the argument is very close to 0, it is much
* more accurate to use {@code log1p(d)} than {@code log(1.0+d)} (due to
* numerical cancellation). The returned result is within 1 ulp (unit in the
* last place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code log1p(+0.0) = +0.0}</li>
* <li>{@code log1p(-0.0) = -0.0}</li>
* <li>{@code log1p((anything < 1)) = NaN}</li>
* <li>{@code log1p(-1.0) = -infinity}</li>
* <li>{@code log1p(+infinity) = +infinity}</li>
* <li>{@code log1p(-infinity) = NaN}</li>
* <li>{@code log1p(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value to compute the {@code ln(1+d)} of.
* @return the natural logarithm of the sum of the argument and 1.
* @since Android 1.0
*/
public static native double log1p(double d);
/**
* Returns the most positive (closest to positive infinity) of the two
* arguments.
* <p>
* Special cases:
* <ul>
* <li>{@code max(NaN, (anything)) = NaN}</li>
* <li>{@code max((anything), NaN) = NaN}</li>
* <li>{@code max(+0.0, -0.0) = +0.0}</li>
* <li>{@code max(-0.0, +0.0) = +0.0}</li>
* </ul>
* </p>
*
* @param d1
* the first argument.
* @param d2
* the second argument.
* @return the larger of {@code d1} and {@code d2}.
* @since Android 1.0
*/
public static double max(double d1, double d2) {
if (d1 > d2)
return d1;
if (d1 < d2)
return d2;
/* if either arg is NaN, return NaN */
if (d1 != d2)
return Double.NaN;
/* max( +0.0,-0.0) == +0.0 */
if (d1 == 0.0
&& ((Double.doubleToLongBits(d1) & Double.doubleToLongBits(d2)) & 0x8000000000000000L) == 0)
return 0.0;
return d1;
}
/**
* Returns the most positive (closest to positive infinity) of the two
* arguments.
* <p>
* Special cases:
* <ul>
* <li>{@code max(NaN, (anything)) = NaN}</li>
* <li>{@code max((anything), NaN) = NaN}</li>
* <li>{@code max(+0.0, -0.0) = +0.0}</li>
* <li>{@code max(-0.0, +0.0) = +0.0}</li>
* </ul>
* </p>
*
* @param f1
* the first argument.
* @param f2
* the second argument.
* @return the larger of {@code f1} and {@code f2}.
* @since Android 1.0
*/
public static float max(float f1, float f2) {
if (f1 > f2)
return f1;
if (f1 < f2)
return f2;
/* if either arg is NaN, return NaN */
if (f1 != f2)
return Float.NaN;
/* max( +0.0,-0.0) == +0.0 */
if (f1 == 0.0f
&& ((Float.floatToIntBits(f1) & Float.floatToIntBits(f2)) & 0x80000000) == 0)
return 0.0f;
return f1;
}
/**
* Returns the most positive (closest to positive infinity) of the two
* arguments.
*
* @param i1
* the first argument.
* @param i2
* the second argument.
* @return the larger of {@code i1} and {@code i2}.
* @since Android 1.0
*/
public static int max(int i1, int i2) {
return i1 > i2 ? i1 : i2;
}
/**
* Returns the most positive (closest to positive infinity) of the two
* arguments.
*
* @param l1
* the first argument.
* @param l2
* the second argument.
* @return the larger of {@code l1} and {@code l2}.
* @since Android 1.0
*/
public static long max(long l1, long l2) {
return l1 > l2 ? l1 : l2;
}
/**
* Returns the most negative (closest to negative infinity) of the two
* arguments.
* <p>
* Special cases:
* <ul>
* <li>{@code min(NaN, (anything)) = NaN}</li>
* <li>{@code min((anything), NaN) = NaN}</li>
* <li>{@code min(+0.0, -0.0) = -0.0}</li>
* <li>{@code min(-0.0, +0.0) = -0.0}</li>
* </ul>
* </p>
*
* @param d1
* the first argument.
* @param d2
* the second argument.
* @return the smaller of {@code d1} and {@code d2}.
* @since Android 1.0
*/
public static double min(double d1, double d2) {
if (d1 > d2)
return d2;
if (d1 < d2)
return d1;
/* if either arg is NaN, return NaN */
if (d1 != d2)
return Double.NaN;
/* min( +0.0,-0.0) == -0.0 */
if (d1 == 0.0
&& ((Double.doubleToLongBits(d1) | Double.doubleToLongBits(d2)) & 0x8000000000000000l) != 0)
return 0.0 * (-1.0);
return d1;
}
/**
* Returns the most negative (closest to negative infinity) of the two
* arguments.
* <p>
* Special cases:
* <ul>
* <li>{@code min(NaN, (anything)) = NaN}</li>
* <li>{@code min((anything), NaN) = NaN}</li>
* <li>{@code min(+0.0, -0.0) = -0.0}</li>
* <li>{@code min(-0.0, +0.0) = -0.0}</li>
* </ul>
* </p>
*
* @param f1
* the first argument.
* @param f2
* the second argument.
* @return the smaller of {@code f1} and {@code f2}.
* @since Android 1.0
*/
public static float min(float f1, float f2) {
if (f1 > f2)
return f2;
if (f1 < f2)
return f1;
/* if either arg is NaN, return NaN */
if (f1 != f2)
return Float.NaN;
/* min( +0.0,-0.0) == -0.0 */
if (f1 == 0.0f
&& ((Float.floatToIntBits(f1) | Float.floatToIntBits(f2)) & 0x80000000) != 0)
return 0.0f * (-1.0f);
return f1;
}
/**
* Returns the most negative (closest to negative infinity) of the two
* arguments.
*
* @param i1
* the first argument.
* @param i2
* the second argument.
* @return the smaller of {@code i1} and {@code i2}.
* @since Android 1.0
*/
public static int min(int i1, int i2) {
return i1 < i2 ? i1 : i2;
}
/**
* Returns the most negative (closest to negative infinity) of the two
* arguments.
*
* @param l1
* the first argument.
* @param l2
* the second argument.
* @return the smaller of {@code l1} and {@code l2}.
* @since Android 1.0
*/
public static long min(long l1, long l2) {
return l1 < l2 ? l1 : l2;
}
/**
* Returns the closest double approximation of the result of raising
* {@code x} to the power of {@code y}.
* <p>
* Special cases:
* <ul>
* <li>{@code pow((anything), +0.0) = 1.0}</li>
* <li>{@code pow((anything), -0.0) = 1.0}</li>
* <li>{@code pow(x, 1.0) = x}</li>
* <li>{@code pow((anything), NaN) = NaN}</li>
* <li>{@code pow(NaN, (anything except 0)) = NaN}</li>
* <li>{@code pow(+/-(|x| > 1), +infinity) = +infinity}</li>
* <li>{@code pow(+/-(|x| > 1), -infinity) = +0.0}</li>
* <li>{@code pow(+/-(|x| < 1), +infinity) = +0.0}</li>
* <li>{@code pow(+/-(|x| < 1), -infinity) = +infinity}</li>
* <li>{@code pow(+/-1.0 , +infinity) = NaN}</li>
* <li>{@code pow(+/-1.0 , -infinity) = NaN}</li>
* <li>{@code pow(+0.0, (+anything except 0, NaN)) = +0.0}</li>
* <li>{@code pow(-0.0, (+anything except 0, NaN, odd integer)) = +0.0}</li>
* <li>{@code pow(+0.0, (-anything except 0, NaN)) = +infinity}</li>
* <li>{@code pow(-0.0, (-anything except 0, NAN, odd integer))} {@code =}
* {@code +infinity}</li>
* <li>{@code pow(-0.0, (odd integer)) = -pow( +0 , (odd integer) )}</li>
* <li>{@code pow(+infinity, (+anything except 0, NaN)) = +infinity}</li>
* <li>{@code pow(+infinity, (-anything except 0, NaN)) = +0.0}</li>
* <li>{@code pow(-infinity, (anything)) = -pow(0, (-anything))}</li>
* <li>{@code pow((-anything), (integer))} {@code =}
* {@code pow(-1,(integer))*pow(+anything,integer) }</li>
* <li>{@code pow((-anything except 0 and inf), (non-integer)) = NAN}</li>
* </ul>
* </p>
*
* @param x
* the base of the operation.
* @param y
* the exponent of the operation.
* @return {@code x} to the power of {@code y}.
* @since Android 1.0
*/
public static native double pow(double x, double y);
// BEGIN android-note
// parameter names changed from d1 / d2 to x / y
// END android-note
/**
* Returns the double conversion of the result of rounding the argument to
* an integer. Tie breaks are rounded towards even.
* <p>
* Special cases:
* <ul>
* <li>{@code rint(+0.0) = +0.0}</li>
* <li>{@code rint(-0.0) = -0.0}</li>
* <li>{@code rint(+infinity) = +infinity}</li>
* <li>{@code rint(-infinity) = -infinity}</li>
* <li>{@code rint(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value to be rounded.
* @return the closest integer to the argument (as a double).
* @since Android 1.0
*/
public static native double rint(double d);
/**
* Returns the result of rounding the argument to an integer. The result is
* equivalent to {@code (long) Math.floor(d+0.5)}.
* <p>
* Special cases:
* <ul>
* <li>{@code round(+0.0) = +0.0}</li>
* <li>{@code round(-0.0) = +0.0}</li>
* <li>{@code round((anything > Long.MAX_VALUE) = Long.MAX_VALUE}</li>
* <li>{@code round((anything < Long.MIN_VALUE) = Long.MIN_VALUE}</li>
* <li>{@code round(+infintiy) = Long.MAX_VALUE}</li>
* <li>{@code round(-infintiy) = Long.MIN_VALUE}</li>
* <li>{@code round(NaN) = +0.0}</li>
* </ul>
* </p>
*
* @param d
* the value to be rounded.
* @return the closest integer to the argument.
* @since Android 1.0
*/
public static long round(double d) {
// check for NaN
if (d != d)
return 0L;
return (long) floor(d + 0.5d);
}
/**
* Returns the result of rounding the argument to an integer. The result is
* equivalent to {@code (int) Math.floor(f+0.5)}.
* <p>
* Special cases:
* <ul>
* <li>{@code round(+0.0) = +0.0}</li>
* <li>{@code round(-0.0) = +0.0}</li>
* <li>{@code round((anything > Integer.MAX_VALUE) = Integer.MAX_VALUE}</li>
* <li>{@code round((anything < Integer.MIN_VALUE) = Integer.MIN_VALUE}</li>
* <li>{@code round(+infintiy) = Integer.MAX_VALUE}</li>
* <li>{@code round(-infintiy) = Integer.MIN_VALUE}</li>
* <li>{@code round(NaN) = +0.0}</li>
* </ul>
* </p>
*
* @param f
* the value to be rounded.
* @return the closest integer to the argument.
* @since Android 1.0
*/
public static int round(float f) {
// check for NaN
if (f != f)
return 0;
return (int) floor(f + 0.5f);
}
/**
* Returns the signum function of the argument. If the argument is less than
* zero, it returns -1.0. If the argument is greater than zero, 1.0 is
* returned. If the argument is either positive or negative zero, the
* argument is returned as result.
* <p>
* Special cases:
* <ul>
* <li>{@code signum(+0.0) = +0.0}</li>
* <li>{@code signum(-0.0) = -0.0}</li>
* <li>{@code signum(+infinity) = +1.0}</li>
* <li>{@code signum(-infinity) = -1.0}</li>
* <li>{@code signum(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose signum has to be computed.
* @return the value of the signum function.
* @since Android 1.0
*/
public static double signum(double d) {
return StrictMath.signum(d);
}
/**
* Returns the signum function of the argument. If the argument is less than
* zero, it returns -1.0. If the argument is greater than zero, 1.0 is
* returned. If the argument is either positive or negative zero, the
* argument is returned as result.
* <p>
* Special cases:
* <ul>
* <li>{@code signum(+0.0) = +0.0}</li>
* <li>{@code signum(-0.0) = -0.0}</li>
* <li>{@code signum(+infinity) = +1.0}</li>
* <li>{@code signum(-infinity) = -1.0}</li>
* <li>{@code signum(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param f
* the value whose signum has to be computed.
* @return the value of the signum function.
* @since Android 1.0
*/
public static float signum(float f) {
return StrictMath.signum(f);
}
/**
* Returns the closest double approximation of the sine of the argument. The
* returned result is within 1 ulp (unit in the last place) of the real
* result.
* <p>
* Special cases:
* <ul>
* <li>{@code sin(+0.0) = +0.0}</li>
* <li>{@code sin(-0.0) = -0.0}</li>
* <li>{@code sin(+infinity) = NaN}</li>
* <li>{@code sin(-infinity) = NaN}</li>
* <li>{@code sin(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the angle whose sin has to be computed, in radians.
* @return the sine of the argument.
* @since Android 1.0
*/
public static native double sin(double d);
/**
* Returns the closest double approximation of the hyperbolic sine of the
* argument. The returned result is within 2.5 ulps (units in the last
* place) of the real result.
* <p>
* Special cases:
* <ul>
* <li>{@code sinh(+0.0) = +0.0}</li>
* <li>{@code sinh(-0.0) = -0.0}</li>
* <li>{@code sinh(+infinity) = +infinity}</li>
* <li>{@code sinh(-infinity) = -infinity}</li>
* <li>{@code sinh(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose hyperbolic sine has to be computed.
* @return the hyperbolic sine of the argument.
* @since Android 1.0
*/
public static native double sinh(double d);
/**
* Returns the closest double approximation of the square root of the
* argument.
* <p>
* Special cases:
* <ul>
* <li>{@code sqrt(+0.0) = +0.0}</li>
* <li>{@code sqrt(-0.0) = -0.0}</li>
* <li>{@code sqrt( (anything < 0) ) = NaN}</li>
* <li>{@code sqrt(+infinity) = +infinity}</li>
* <li>{@code sqrt(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose square root has to be computed.
* @return the square root of the argument.
* @since Android 1.0
*/
public static native double sqrt(double d);
/**
* Returns the closest double approximation of the tangent of the argument.
* The returned result is within 1 ulp (unit in the last place) of the real
* result.
* <p>
* Special cases:
* <ul>
* <li>{@code tan(+0.0) = +0.0}</li>
* <li>{@code tan(-0.0) = -0.0}</li>
* <li>{@code tan(+infinity) = NaN}</li>
* <li>{@code tan(-infinity) = NaN}</li>
* <li>{@code tan(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the angle whose tangens has to be computed, in radians.
* @return the tangent of the argument.
* @since Android 1.0
*/
public static native double tan(double d);
/**
* Returns the closest double approximation of the hyperbolic tangent of the
* argument. The absolute value is always less than 1. The returned result
* is within 2.5 ulps (units in the last place) of the real result. If the
* real result is within 0.5ulp of 1 or -1, it should return exactly +1 or
* -1.
* <p>
* Special cases:
* <ul>
* <li>{@code tanh(+0.0) = +0.0}</li>
* <li>{@code tanh(-0.0) = -0.0}</li>
* <li>{@code tanh(+infinity) = +1.0}</li>
* <li>{@code tanh(-infinity) = -1.0}</li>
* <li>{@code tanh(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the value whose hyperbolic tangent has to be computed.
* @return the hyperbolic tangent of the argument.
* @since Android 1.0
*/
public static native double tanh(double d);
/**
* Returns a pseudo-random number between 0.0 (inclusive) and 1.0
* (exclusive).
*
* @return a pseudo-random number.
* @since Android 1.0
*/
public static double random() {
if (random == null) {
random = new java.util.Random();
}
return random.nextDouble();
}
/**
* Returns the measure in radians of the supplied degree angle. The result
* is {@code angdeg / 180 * pi}.
* <p>
* Special cases:
* <ul>
* <li>{@code toRadians(+0.0) = +0.0}</li>
* <li>{@code toRadians(-0.0) = -0.0}</li>
* <li>{@code toRadians(+infinity) = +infinity}</li>
* <li>{@code toRadians(-infinity) = -infinity}</li>
* <li>{@code toRadians(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param angdeg
* an angle in degrees.
* @return the radian measure of the angle.
* @since Android 1.0
*/
public static double toRadians(double angdeg) {
return angdeg / 180d * PI;
}
/**
* Returns the measure in degrees of the supplied radian angle. The result
* is {@code angrad * 180 / pi}.
* <p>
* Special cases:
* <ul>
* <li>{@code toDegrees(+0.0) = +0.0}</li>
* <li>{@code toDegrees(-0.0) = -0.0}</li>
* <li>{@code toDegrees(+infinity) = +infinity}</li>
* <li>{@code toDegrees(-infinity) = -infinity}</li>
* <li>{@code toDegrees(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param angrad
* an angle in radians.
* @return the degree measure of the angle.
* @since Android 1.0
*/
public static double toDegrees(double angrad) {
return angrad * 180d / PI;
}
/**
* Returns the argument's ulp (unit in the last place). The size of a ulp of
* a double value is the positive distance between this value and the double
* value next larger in magnitude. For non-NaN {@code x},
* {@code ulp(-x) == ulp(x)}.
* <p>
* Special cases:
* <ul>
* <li>{@code ulp(+0.0) = Double.MIN_VALUE}</li>
* <li>{@code ulp(-0.0) = Double.MIN_VALUE}</li>
* <li>{@code ulp(+infintiy) = infinity}</li>
* <li>{@code ulp(-infintiy) = infinity}</li>
* <li>{@code ulp(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param d
* the floating-point value to compute ulp of.
* @return the size of a ulp of the argument.
* @since Android 1.0
*/
public static double ulp(double d) {
// special cases
if (Double.isInfinite(d)) {
return Double.POSITIVE_INFINITY;
} else if (d == Double.MAX_VALUE || d == -Double.MAX_VALUE) {
return pow(2, 971);
}
d = abs(d);
return nextafter(d, Double.MAX_VALUE) - d;
}
/**
* Returns the argument's ulp (unit in the last place). The size of a ulp of
* a float value is the positive distance between this value and the float
* value next larger in magnitude. For non-NaN {@code x},
* {@code ulp(-x) == ulp(x)}.
* <p>
* Special cases:
* <ul>
* <li>{@code ulp(+0.0) = Float.MIN_VALUE}</li>
* <li>{@code ulp(-0.0) = Float.MIN_VALUE}</li>
* <li>{@code ulp(+infintiy) = infinity}</li>
* <li>{@code ulp(-infintiy) = infinity}</li>
* <li>{@code ulp(NaN) = NaN}</li>
* </ul>
* </p>
*
* @param f
* the floating-point value to compute ulp of.
* @return the size of a ulp of the argument.
* @since Android 1.0
*/
public static float ulp(float f) {
// special cases
if (Float.isNaN(f)) {
return Float.NaN;
} else if (Float.isInfinite(f)) {
return Float.POSITIVE_INFINITY;
} else if (f == Float.MAX_VALUE || f == -Float.MAX_VALUE) {
return (float) pow(2, 104);
}
f = abs(f);
return nextafterf(f, Float.MAX_VALUE) - f;
}
private native static double nextafter(double x, double y);
private native static float nextafterf(float x, float y);
}
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