Class DoubleDouble
- java.lang.Object
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- gov.nih.mipav.util.DoubleDouble
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Cloneable
,java.lang.Comparable
public class DoubleDouble extends java.lang.Object implements java.io.Serializable, java.lang.Comparable, java.lang.Cloneable
Immutable, extended-precision floating-point numbers which maintain 106 bits (approximately 30 decimal digits) of precision.A DoubleDouble uses a representation containing two double-precision values. A number x is represented as a pair of doubles, x.hi and x.lo, such that the number represented by x is x.hi + x.lo, where
|x.lo| <= 0.5*ulp(x.hi)
and ulp(y) means "unit in the last place of y". The basic arithmetic operations are implemented using convenient properties of IEEE-754 floating-point arithmetic.The range of values which can be represented is the same as in IEEE-754. The precision of the representable numbers is twice as great as IEEE-754 double precision.
The correctness of the arithmetic algorithms relies on operations being performed with standard IEEE-754 double precision and rounding. This is the Java standard arithmetic model, but for performance reasons Java implementations are not constrained to using this standard by default. Some processors (notably the Intel Pentium architecure) perform floating point operations in (non-IEEE-754-standard) extended-precision. A JVM implementation may choose to use the non-standard extended-precision as its default arithmetic mode. To prevent this from happening, this code uses the Java strictfp modifier, which forces all operations to take place in the standard IEEE-754 rounding model.
The API provides a value-oriented interface. DoubleDouble values are immutable; operations on them return new objects carrying the result of the operation. This provides a much simpler semantics for writing DoubleDouble expressions, and Java memory management is efficient enough that this imposes very little performance penalty.
This implementation uses algorithms originally designed variously by Knuth, Kahan, Dekker, and Linnainmaa. Douglas Priest developed the first C implementation of these techniques. Other more recent C++ implementation are due to Keith M. Briggs and David Bailey et al.
References
- Priest, D., Algorithms for Arbitrary Precision Floating Point Arithmetic, in P. Kornerup and D. Matula, Eds., Proc. 10th Symposium on Computer Arithmetic, IEEE Computer Society Press, Los Alamitos, Calif., 1991.
- Yozo Hida, Xiaoye S. Li and David H. Bailey, Quad-Double Arithmetic: Algorithms, Implementation, and Application, manuscript, Oct 2000; Lawrence Berkeley National Laboratory Report BNL-46996.
- David Bailey, High Precision Software Directory; http://crd.lbl.gov/~dhbailey/mpdist/index.html
This class is based on the DoubleDouble created by Martin Davis and distributed under the following license:Copyright (c) 2008-2012 Martin Davis. All Rights Reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY Martin Davis "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- Author:
- Martin Davis
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description static DoubleDouble
E
The value nearest to the constant e (the natural logarithm base).static double
EPS
The smallest representable relative difference between two {link @ DoubleDouble} valuesdouble
hi
The high-order component of the double-double precision value.double
lo
The low-order component of the double-double precision value.private static int
MAX_PRINT_DIGITS
static DoubleDouble
NaN
A value representing the result of an operation which does not return a valid number.static DoubleDouble
NEGATIVE_INFINITY
private static DoubleDouble
ONE
static DoubleDouble
PI
The value nearest to the constant Pi.static DoubleDouble
PI_2
The value nearest to the constant Pi / 2.static DoubleDouble
POSITIVE_INFINITY
private static java.lang.String
SCI_NOT_EXPONENT_CHAR
private static java.lang.String
SCI_NOT_ZERO
private static double
SPLIT
The value to split a double-precision value on during multiplicationprivate static DoubleDouble
TEN
static DoubleDouble
TWO_PI
The value nearest to the constant 2 * Pi.
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Constructor Summary
Constructors Constructor Description DoubleDouble()
Creates a new DoubleDouble with value 0.0.DoubleDouble(double x)
Creates a new DoubleDouble with value x.DoubleDouble(double hi, double lo)
Creates a new DoubleDouble with value (hi, lo).DoubleDouble(DoubleDouble dd)
Creates a new DoubleDouble with value equal to the argument.DoubleDouble(java.lang.String str)
Creates a new DoubleDouble with value equal to the argument.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description DoubleDouble
abs()
Returns the absolute value of this value.DoubleDouble
acos()
For all -1 < x < 1, arccos(x) = PI/2 - arcsin(x)DoubleDouble
add(DoubleDouble y)
Returns a DoubleDouble whose value is (this + y).DoubleDouble
asin()
For all -1 < x < 1, arcsin(x) = x + x**3/(2*3) + (1 * 3 * x**5)/(2 * 4 * 5) + (1 * 3 * 5 * x**7)/(2 * 4 * 6 * 7) + ...DoubleDouble
atan()
For -1 < x < 1, arctan(x) = x - x**3/3 + x**5/5 - x**7/7 + ...DoubleDouble
atan2(DoubleDouble x)
The atan of this(the imaginary y component) divided by the real component x Value will range from -PI to PI.DoubleDouble
BernoulliA(int n)
DoubleDouble
BernoulliB(int n)
DoubleDouble
ceil()
Returns the smallest (closest to negative infinity) value that is not less than the argument and is equal to a mathematical integer.DoubleDouble
Ci()
void
cisia(DoubleDouble x, DoubleDouble Ci, DoubleDouble Si)
This is a port of subroutine CISIA which computes cosine and sine integrals from Computation of Special Functions by Shanjie Zhang and Jianming Jin.java.lang.Object
clone()
Creates and returns a copy of this value.int
compareTo(java.lang.Object o)
Compares two DoubleDouble objects numerically.DoubleDouble
cos()
For all real x, cos(x) = 1 - x**2/2!DoubleDouble
cosh()
For all real x, cosh(x) = 1 + x**2/2!DoubleDouble
divide(DoubleDouble y)
Returns a DoubleDouble whose value is (this / y).double
doubleValue()
Converts this value to the nearest double-precision number.java.lang.String
dump()
Dumps the components of this number to a string.boolean
equals(DoubleDouble y)
Tests whether this value is equal to another DoubleDouble value.DoubleDouble
erf()
DoubleDouble
exp()
For all real, x exp(x) = 1 + x + x**2/2!private java.lang.String
extractSignificantDigits(boolean insertDecimalPoint, int[] magnitude)
Extracts the significant digits in the decimal representation of the argument.DoubleDouble
factorial(int fac)
DoubleDouble
floor()
Returns the largest (closest to positive infinity) value that is not greater than the argument and is equal to a mathematical integer.boolean
ge(DoubleDouble y)
Tests whether this value is greater than or equals to another DoubleDouble value.private java.lang.String
getSpecialNumberString()
Returns the string for this value if it has a known representation.boolean
gt(DoubleDouble y)
Tests whether this value is greater than another DoubleDouble value.private void
init(double x)
private void
init(double hi, double lo)
private void
init(DoubleDouble dd)
int
intValue()
Converts this value to the nearest integer.boolean
isInfinite()
boolean
isNaN()
Tests whether this value is NaN.boolean
isNegative()
Tests whether this value is less than 0.boolean
isNegativeFinite()
boolean
isNegativeInfinity()
boolean
isPositive()
Tests whether this value is greater than 0.boolean
isPositiveFinite()
boolean
isPositiveInfinity()
boolean
isZero()
Tests whether this value is equal to 0.boolean
le(DoubleDouble y)
Tests whether this value is less than or equal to another DoubleDouble value.DoubleDouble
log()
For x > 0, ratio = (x-1)/(x+1), log(x) = 2(ratio + ratio**3/3 + ratio**5/5 + ...)boolean
lt(DoubleDouble y)
Tests whether this value is less than another DoubleDouble value.private static int
magnitude(double x)
Determines the decimal magnitude of a number.DoubleDouble
max(DoubleDouble x)
DoubleDouble
min(DoubleDouble x)
DoubleDouble
mod(DoubleDouble x)
DoubleDouble
multiply(DoubleDouble y)
Returns a DoubleDouble whose value is (this * y).boolean
ne(DoubleDouble y)
DoubleDouble
negate()
Returns a DoubleDouble whose value is -this.static DoubleDouble
parse(java.lang.String str)
Converts a string representation of a real number into a DoubleDouble value.DoubleDouble
pow(double x)
DoubleDouble
pow(int exp)
Computes the value of this number raised to an integral power.DoubleDouble
pow(DoubleDouble x)
DoubleDouble
reciprocal()
Returns a DoubleDouble whose value is 1 / this.DoubleDouble
rint()
Rounds this value to the nearest integer.private DoubleDouble
selfAdd(DoubleDouble y)
Adds the argument to the value of this.private DoubleDouble
selfMultiply(DoubleDouble y)
Multiplies this by the argument, returning this.DoubleDouble
Si()
int
signum()
Returns an integer indicating the sign of this value.DoubleDouble
sin()
For all real x, sin(x) = x - x**3/3!DoubleDouble
sinh()
For all real x, sinh(x) = x + x**3/3!DoubleDouble
sqr()
Computes the square of this value.DoubleDouble
sqrt()
Computes the positive square root of this value.private static java.lang.String
stringOfChar(char ch, int len)
Creates a string of a given length containing the given characterDoubleDouble
subtract(DoubleDouble y)
Returns a DoubleDouble whose value is (this - y).DoubleDouble
tan()
For -PI/2 < x < PI/2, tan(x) = x + (x**3)/3 + 2*(x**5)/15 + 17*(x**7)/315 + 62*(x**9)/2835 + ... + (2**(2*n))*((2**(2*n)) - 1)*Bn*(x**(2*n-1))/((2*n)!)java.lang.String
toSciNotation()
Returns the string representation of this value in scientific notation.java.lang.String
toStandardNotation()
Returns the string representation of this value in standard notation.java.lang.String
toString()
Returns a string representation of this number, in either standard or scientific notation.DoubleDouble
trunc()
Returns the integer which is largest in absolute value and not further from zero than this value.static DoubleDouble
valueOf(double x)
Converts the double argument to a DoubleDouble number.static DoubleDouble
valueOf(java.lang.String str)
Converts the string argument to a DoubleDouble number.
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Field Detail
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PI
public static final DoubleDouble PI
The value nearest to the constant Pi.
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TWO_PI
public static final DoubleDouble TWO_PI
The value nearest to the constant 2 * Pi.
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PI_2
public static final DoubleDouble PI_2
The value nearest to the constant Pi / 2.
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E
public static final DoubleDouble E
The value nearest to the constant e (the natural logarithm base).
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NaN
public static final DoubleDouble NaN
A value representing the result of an operation which does not return a valid number.
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POSITIVE_INFINITY
public static final DoubleDouble POSITIVE_INFINITY
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NEGATIVE_INFINITY
public static final DoubleDouble NEGATIVE_INFINITY
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EPS
public static final double EPS
The smallest representable relative difference between two {link @ DoubleDouble} values- See Also:
- Constant Field Values
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SPLIT
private static final double SPLIT
The value to split a double-precision value on during multiplication- See Also:
- Constant Field Values
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hi
public double hi
The high-order component of the double-double precision value.
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lo
public double lo
The low-order component of the double-double precision value.
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MAX_PRINT_DIGITS
private static final int MAX_PRINT_DIGITS
- See Also:
- Constant Field Values
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TEN
private static final DoubleDouble TEN
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ONE
private static final DoubleDouble ONE
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SCI_NOT_EXPONENT_CHAR
private static final java.lang.String SCI_NOT_EXPONENT_CHAR
- See Also:
- Constant Field Values
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SCI_NOT_ZERO
private static final java.lang.String SCI_NOT_ZERO
- See Also:
- Constant Field Values
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Constructor Detail
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DoubleDouble
public DoubleDouble()
Creates a new DoubleDouble with value 0.0.
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DoubleDouble
public DoubleDouble(double x)
Creates a new DoubleDouble with value x.- Parameters:
x
- the value to initialize
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DoubleDouble
public DoubleDouble(double hi, double lo)
Creates a new DoubleDouble with value (hi, lo).- Parameters:
hi
- the high-order componentlo
- the high-order component
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DoubleDouble
public DoubleDouble(DoubleDouble dd)
Creates a new DoubleDouble with value equal to the argument.- Parameters:
dd
- the value to initialize
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DoubleDouble
public DoubleDouble(java.lang.String str) throws java.lang.NumberFormatException
Creates a new DoubleDouble with value equal to the argument.- Parameters:
str
- the value to initialize by- Throws:
java.lang.NumberFormatException
- if str is not a valid representation of a number
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Method Detail
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valueOf
public static DoubleDouble valueOf(java.lang.String str) throws java.lang.NumberFormatException
Converts the string argument to a DoubleDouble number.- Parameters:
str
- a string containing a representation of a numeric value- Returns:
- the extended precision version of the value
- Throws:
java.lang.NumberFormatException
- if s is not a valid representation of a number
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valueOf
public static DoubleDouble valueOf(double x)
Converts the double argument to a DoubleDouble number.- Parameters:
x
- a numeric value- Returns:
- the extended precision version of the value
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clone
public java.lang.Object clone()
Creates and returns a copy of this value.- Overrides:
clone
in classjava.lang.Object
- Returns:
- a copy of this value
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init
private void init(double x)
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init
private void init(double hi, double lo)
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init
private void init(DoubleDouble dd)
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add
public DoubleDouble add(DoubleDouble y)
Returns a DoubleDouble whose value is (this + y).- Parameters:
y
- the addend- Returns:
- (this + y)
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selfAdd
private DoubleDouble selfAdd(DoubleDouble y)
Adds the argument to the value of this. To prevent altering constants, this method must only be used on values known to be newly created.- Parameters:
y
- the addend- Returns:
- this, with its value incremented by y
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subtract
public DoubleDouble subtract(DoubleDouble y)
Returns a DoubleDouble whose value is (this - y).- Parameters:
y
- the subtrahend- Returns:
- (this - y)
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negate
public DoubleDouble negate()
Returns a DoubleDouble whose value is -this.- Returns:
- -this
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multiply
public DoubleDouble multiply(DoubleDouble y)
Returns a DoubleDouble whose value is (this * y).- Parameters:
y
- the multiplicand- Returns:
- (this * y)
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selfMultiply
private DoubleDouble selfMultiply(DoubleDouble y)
Multiplies this by the argument, returning this. To prevent altering constants, this method must only be used on values known to be newly created.- Parameters:
y
- a DoubleDouble value to multiply by- Returns:
- this
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divide
public DoubleDouble divide(DoubleDouble y)
Returns a DoubleDouble whose value is (this / y).- Parameters:
y
- the divisor- Returns:
- (this / y)
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reciprocal
public DoubleDouble reciprocal()
Returns a DoubleDouble whose value is 1 / this.- Returns:
- the reciprocal of this value
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floor
public DoubleDouble floor()
Returns the largest (closest to positive infinity) value that is not greater than the argument and is equal to a mathematical integer. Special cases:- If this value is NaN, returns NaN.
- Returns:
- the largest (closest to positive infinity) value that is not greater than the argument and is equal to a mathematical integer.
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ceil
public DoubleDouble ceil()
Returns the smallest (closest to negative infinity) value that is not less than the argument and is equal to a mathematical integer. Special cases:- If this value is NaN, returns NaN.
- Returns:
- the smallest (closest to negative infinity) value that is not less than the argument and is equal to a mathematical integer.
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signum
public int signum()
Returns an integer indicating the sign of this value.- if this value is > 0, returns 1
- if this value is < 0, returns -1
- if this value is = 0, returns 0
- if this value is NaN, returns 0
- Returns:
- an integer indicating the sign of this value
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rint
public DoubleDouble rint()
Rounds this value to the nearest integer. The value is rounded to an integer by adding 1/2 and taking the floor of the result. Special cases:- If this value is NaN, returns NaN.
- Returns:
- this value rounded to the nearest integer
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trunc
public DoubleDouble trunc()
Returns the integer which is largest in absolute value and not further from zero than this value. Special cases:- If this value is NaN, returns NaN.
- Returns:
- the integer which is largest in absolute value and not further from zero than this value
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abs
public DoubleDouble abs()
Returns the absolute value of this value. Special cases:- If this value is NaN, it is returned.
- Returns:
- the absolute value of this value
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sqr
public DoubleDouble sqr()
Computes the square of this value.- Returns:
- the square of this value.
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sqrt
public DoubleDouble sqrt()
Computes the positive square root of this value. If the number is NaN or negative, NaN is returned.- Returns:
- the positive square root of this number. If the argument is NaN or less than zero, the result is NaN.
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exp
public DoubleDouble exp()
For all real, x exp(x) = 1 + x + x**2/2! + x**3/3! + x**4/4! + ...- Returns:
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log
public DoubleDouble log()
For x > 0, ratio = (x-1)/(x+1), log(x) = 2(ratio + ratio**3/3 + ratio**5/5 + ...)- Returns:
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sinh
public DoubleDouble sinh()
For all real x, sinh(x) = x + x**3/3! + x**5/5! + x**7/7! + ... + x**(2n+1)/(2n+1)! + ...- Returns:
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cosh
public DoubleDouble cosh()
For all real x, cosh(x) = 1 + x**2/2! + x**4/4! + x**6/6! + ... + x**(2*n)/((2*n)!) + ...- Returns:
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sin
public DoubleDouble sin()
For all real x, sin(x) = x - x**3/3! + x**5/5! - x**7/7! + ...- Returns:
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erf
public DoubleDouble erf()
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cos
public DoubleDouble cos()
For all real x, cos(x) = 1 - x**2/2! + x**4/4! - x**6/6! + ...- Returns:
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tan
public DoubleDouble tan()
For -PI/2 < x < PI/2, tan(x) = x + (x**3)/3 + 2*(x**5)/15 + 17*(x**7)/315 + 62*(x**9)/2835 + ... + (2**(2*n))*((2**(2*n)) - 1)*Bn*(x**(2*n-1))/((2*n)!) + ...- Returns:
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asin
public DoubleDouble asin()
For all -1 < x < 1, arcsin(x) = x + x**3/(2*3) + (1 * 3 * x**5)/(2 * 4 * 5) + (1 * 3 * 5 * x**7)/(2 * 4 * 6 * 7) + ...- Returns:
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acos
public DoubleDouble acos()
For all -1 < x < 1, arccos(x) = PI/2 - arcsin(x)- Returns:
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atan2
public DoubleDouble atan2(DoubleDouble x)
The atan of this(the imaginary y component) divided by the real component x Value will range from -PI to PI. Strays a bit from actual atan2 definition which recognizes positive zero and negative zero. Here both positive zero and negative zero are combined as zero.- Parameters:
x
-- Returns:
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atan
public DoubleDouble atan()
For -1 < x < 1, arctan(x) = x - x**3/3 + x**5/5 - x**7/7 + ... For x > 1, arctan(x) = PI/2 - 1/x + 1/(3*x**3) - 1/(5*x**5) +1/(7*x**7) - ... * For x < -1, arctan(x) = -PI/2 - 1/x + 1/(3*x**3) - 1/(5*x**5) +1/(7*x**7) - ...- Returns:
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BernoulliA
public DoubleDouble BernoulliA(int n)
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BernoulliB
public DoubleDouble BernoulliB(int n)
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Ci
public DoubleDouble Ci()
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Si
public DoubleDouble Si()
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cisia
public void cisia(DoubleDouble x, DoubleDouble Ci, DoubleDouble Si)
This is a port of subroutine CISIA which computes cosine and sine integrals from Computation of Special Functions by Shanjie Zhang and Jianming Jin. Waiting for Professor Jin's reply. Dear Professor Jianming Jin: There is an error in subroutine CISIA in Computation of Special Functions. Under ELSE IF (x .LE. 32.0D0) THEN in the DO 25 K =M,1,-1 loop the values of BJ(1) thru BJ(M) are set. You then have the loop DO 30 K=2,M,2 30 XS=XS+2.0D0*BJ(K+1) so for M even the value of BJ(M+1) will be used, but the value of BJ(M+1) has not been set. Sincerely, William Gandler
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factorial
public DoubleDouble factorial(int fac)
- Parameters:
fac
-- Returns:
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pow
public DoubleDouble pow(int exp)
Computes the value of this number raised to an integral power. Follows semantics of Java Math.pow as closely as possible.- Parameters:
exp
- the integer exponent- Returns:
- x raised to the integral power exp
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pow
public DoubleDouble pow(double x)
- Parameters:
x
- the double exponent- Returns:
- a raised to the double power x For a > 0, base = x * log(a), a**x = 1 + base + base**2/2! + base**3/3! + ...
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mod
public DoubleDouble mod(DoubleDouble x)
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pow
public DoubleDouble pow(DoubleDouble x)
- Parameters:
x
- the DoubleDouble exponent- Returns:
- a raised to the DoubleDouble power x For a > 0, base = x * log(a), a**x = 1 + base + base**2/2! + base**3/3! + ...
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min
public DoubleDouble min(DoubleDouble x)
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max
public DoubleDouble max(DoubleDouble x)
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doubleValue
public double doubleValue()
Converts this value to the nearest double-precision number.- Returns:
- the nearest double-precision number to this value
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intValue
public int intValue()
Converts this value to the nearest integer.- Returns:
- the nearest integer to this value
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isPositiveFinite
public boolean isPositiveFinite()
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isNegativeFinite
public boolean isNegativeFinite()
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isPositiveInfinity
public boolean isPositiveInfinity()
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isNegativeInfinity
public boolean isNegativeInfinity()
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isZero
public boolean isZero()
Tests whether this value is equal to 0.- Returns:
- true if this value is equal to 0
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isNegative
public boolean isNegative()
Tests whether this value is less than 0.- Returns:
- true if this value is less than 0
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isPositive
public boolean isPositive()
Tests whether this value is greater than 0.- Returns:
- true if this value is greater than 0
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isNaN
public boolean isNaN()
Tests whether this value is NaN.- Returns:
- true if this value is NaN
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isInfinite
public boolean isInfinite()
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equals
public boolean equals(DoubleDouble y)
Tests whether this value is equal to another DoubleDouble value.- Parameters:
y
- a DoubleDouble value- Returns:
- true if this value = y
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ne
public boolean ne(DoubleDouble y)
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gt
public boolean gt(DoubleDouble y)
Tests whether this value is greater than another DoubleDouble value.- Parameters:
y
- a DoubleDouble value- Returns:
- true if this value > y
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ge
public boolean ge(DoubleDouble y)
Tests whether this value is greater than or equals to another DoubleDouble value.- Parameters:
y
- a DoubleDouble value- Returns:
- true if this value >= y
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lt
public boolean lt(DoubleDouble y)
Tests whether this value is less than another DoubleDouble value.- Parameters:
y
- a DoubleDouble value- Returns:
- true if this value < y
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le
public boolean le(DoubleDouble y)
Tests whether this value is less than or equal to another DoubleDouble value.- Parameters:
y
- a DoubleDouble value- Returns:
- true if this value <= y
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compareTo
public int compareTo(java.lang.Object o)
Compares two DoubleDouble objects numerically.- Specified by:
compareTo
in interfacejava.lang.Comparable
- Returns:
- -1,0 or 1 depending on whether this value is less than, equal to or greater than the value of o
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dump
public java.lang.String dump()
Dumps the components of this number to a string.- Returns:
- a string showing the components of the number
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toString
public java.lang.String toString()
Returns a string representation of this number, in either standard or scientific notation. If the magnitude of the number is in the range [ 10-3, 108 ] standard notation will be used. Otherwise, scientific notation will be used.- Overrides:
toString
in classjava.lang.Object
- Returns:
- a string representation of this number
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toStandardNotation
public java.lang.String toStandardNotation()
Returns the string representation of this value in standard notation.- Returns:
- the string representation in standard notation
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toSciNotation
public java.lang.String toSciNotation()
Returns the string representation of this value in scientific notation.- Returns:
- the string representation in scientific notation
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extractSignificantDigits
private java.lang.String extractSignificantDigits(boolean insertDecimalPoint, int[] magnitude)
Extracts the significant digits in the decimal representation of the argument. A decimal point may be optionally inserted in the string of digits (as long as its position lies within the extracted digits - if not, the caller must prepend or append the appropriate zeroes and decimal point).- Parameters:
y
- the number to extract ( >= 0)decimalPointPos
- the position in which to insert a decimal point- Returns:
- the string containing the significant digits and possibly a decimal point
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stringOfChar
private static java.lang.String stringOfChar(char ch, int len)
Creates a string of a given length containing the given character- Parameters:
ch
- the character to be repeatedlen
- the len of the desired string- Returns:
- the string
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getSpecialNumberString
private java.lang.String getSpecialNumberString()
Returns the string for this value if it has a known representation. (E.g. NaN or 0.0)- Returns:
- the string for this special number
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magnitude
private static int magnitude(double x)
Determines the decimal magnitude of a number. The magnitude is the exponent of the greatest power of 10 which is less than or equal to the number.- Parameters:
x
- the number to find the magnitude of- Returns:
- the decimal magnitude of x
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parse
public static DoubleDouble parse(java.lang.String str) throws java.lang.NumberFormatException
Converts a string representation of a real number into a DoubleDouble value. The format accepted is similar to the standard Java real number syntax. It is defined by the following regular expression:[+|-] {digit} [ . {digit} ] [ ( e | E ) [+|-] {digit}+
- Parameters:
str
- the string to parse- Returns:
- the value of the parsed number
- Throws:
java.lang.NumberFormatException
- if str is not a valid representation of a number
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