Java Code Examples for sun.misc.FloatConsts#MAX_EXPONENT
The following examples show how to use
sun.misc.FloatConsts#MAX_EXPONENT .
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Example 1
| Source File: FpUtils.java From java-n-IDE-for-Android with Apache License 2.0 | 4 votes |
|
/**
* Return <code>f </code>×
* 2<sup><code>scale_factor</code></sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See <a
* href="http://java.sun.com/docs/books/jls/second_edition/html/typesValues.doc.html#9208">§4.2.3</a>
* of the <a href="http://java.sun.com/docs/books/jls/html/">Java
* Language Specification</a> for a discussion of floating-point
* value set. If the exponent of the result is between the
* <code>float</code>'s minimum exponent and maximum exponent, the
* answer is calculated exactly. If the exponent of the result
* would be larger than <code>float</code>'s maximum exponent, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when <code>scalb(x, n)</code>
* is subnormal, <code>scalb(scalb(x, n), -n)</code> may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as <code>f</code>.
*
*<p>
* Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scale_factor power of 2 used to scale <code>f</code>
* @return <code>f * </code>2<sup><code>scale_factor</code></sup>
* @author Joseph D. Darcy
*/
public static float scalb(float f, int scale_factor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scale_factor = Math.max(Math.min(scale_factor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scale_factor));
}
Example 2
| Source File: FpUtils.java From openjdk-8 with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 3
| Source File: FpUtils.java From hottub with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 4
| Source File: Math.java From jdk8u-jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 5
| Source File: FpUtils.java From javaide with GNU General Public License v3.0 | 4 votes |
|
/**
* Return <code>f </code>×
* 2<sup><code>scale_factor</code></sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See <a
* href="http://java.sun.com/docs/books/jls/second_edition/html/typesValues.doc.html#9208">§4.2.3</a>
* of the <a href="http://java.sun.com/docs/books/jls/html/">Java
* Language Specification</a> for a discussion of floating-point
* value set. If the exponent of the result is between the
* <code>float</code>'s minimum exponent and maximum exponent, the
* answer is calculated exactly. If the exponent of the result
* would be larger than <code>float</code>'s maximum exponent, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when <code>scalb(x, n)</code>
* is subnormal, <code>scalb(scalb(x, n), -n)</code> may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as <code>f</code>.
*
*<p>
* Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scale_factor power of 2 used to scale <code>f</code>
* @return <code>f * </code>2<sup><code>scale_factor</code></sup>
* @author Joseph D. Darcy
*/
public static float scalb(float f, int scale_factor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scale_factor = Math.max(Math.min(scale_factor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scale_factor));
}
Example 6
| Source File: FpUtils.java From javaide with GNU General Public License v3.0 | 4 votes |
|
/**
* Returns unbiased exponent of a <code>float</code>; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
// break;
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
// break;
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
// break;
}
}
Example 7
| Source File: Math.java From openjdk-8 with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 8
| Source File: Math.java From openjdk-jdk8u-backup with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 9
| Source File: FpUtils.java From openjdk-jdk8u with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 10
| Source File: Math.java From openjdk-jdk8u with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 11
| Source File: Math.java From jdk1.8-source-analysis with Apache License 2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 12
| Source File: FpUtils.java From java-n-IDE-for-Android with Apache License 2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a <code>float</code>; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
// break;
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
// break;
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
// break;
}
}
Example 13
| Source File: FpUtils.java From jdk8u_jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 14
| Source File: Math.java From hottub with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 15
| Source File: Math.java From jdk8u60 with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 16
| Source File: Math.java From openjdk-8-source with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 17
| Source File: FpUtils.java From jdk8u-dev-jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 18
| Source File: FpUtils.java From dragonwell8_jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 19
| Source File: Math.java From jdk8u-dev-jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
Example 20
| Source File: Math.java From j2objc with Apache License 2.0 | 4 votes |
|
/**
* Returns {@code f} ×
* 2<sup>{@code scaleFactor}</sup> rounded as if performed
* by a single correctly rounded floating-point multiply to a
* member of the float value set. See the Java
* Language Specification for a discussion of floating-point
* value sets. If the exponent of the result is between {@link
* Float#MIN_EXPONENT} and {@link Float#MAX_EXPONENT}, the
* answer is calculated exactly. If the exponent of the result
* would be larger than {@code Float.MAX_EXPONENT}, an
* infinity is returned. Note that if the result is subnormal,
* precision may be lost; that is, when {@code scalb(x, n)}
* is subnormal, {@code scalb(scalb(x, n), -n)} may not equal
* <i>x</i>. When the result is non-NaN, the result has the same
* sign as {@code f}.
*
* <p>Special cases:
* <ul>
* <li> If the first argument is NaN, NaN is returned.
* <li> If the first argument is infinite, then an infinity of the
* same sign is returned.
* <li> If the first argument is zero, then a zero of the same
* sign is returned.
* </ul>
*
* @param f number to be scaled by a power of two.
* @param scaleFactor power of 2 used to scale {@code f}
* @return {@code f} × 2<sup>{@code scaleFactor}</sup>
* @since 1.6
*/
public static float scalb(float f, int scaleFactor) {
// magnitude of a power of two so large that scaling a finite
// nonzero value by it would be guaranteed to over or
// underflow; due to rounding, scaling down takes takes an
// additional power of two which is reflected here
final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
FloatConsts.SIGNIFICAND_WIDTH + 1;
// Make sure scaling factor is in a reasonable range
scaleFactor = Math.max(Math.min(scaleFactor, MAX_SCALE), -MAX_SCALE);
/*
* Since + MAX_SCALE for float fits well within the double
* exponent range and + float -> double conversion is exact
* the multiplication below will be exact. Therefore, the
* rounding that occurs when the double product is cast to
* float will be the correctly rounded float result. Since
* all operations other than the final multiply will be exact,
* it is not necessary to declare this method strictfp.
*/
return (float)((double)f*powerOfTwoD(scaleFactor));
}
