| java.lang.Object
 org.apache.commons.math.util.MathUtils
| MathUtils | | final public class MathUtils (Code) | | Some useful additions to the built-in functions in
Math .
version:
$Revision: 321510 $ $Date: 2005-10-15 15:33:14 -0700 (Sat, 15 Oct 2005) $ |
| Method Summary | |
| public static int | addAndCheck(int x, int y)
Add two integers, checking for overflow. | | public static long | binomialCoefficient(int n, int k)
Returns an exact representation of the Binomial
Coefficient, "n choose k", the number of
k-element subsets that can be selected from an
n-element set.
Preconditions:
-
0 <= k <= n (otherwise
IllegalArgumentException is thrown)
- The result is small enough to fit into a
long. | | public static double | binomialCoefficientDouble(int n, int k)
Returns a double representation of the Binomial
Coefficient, "n choose k", the number of
k-element subsets that can be selected from an
n-element set.
Preconditions:
-
0 <= k <= n (otherwise
IllegalArgumentException is thrown)
- The result is small enough to fit into a
double. | | public static double | binomialCoefficientLog(int n, int k)
Returns the natural log of the Binomial
Coefficient, "n choose k", the number of
k-element subsets that can be selected from an
n-element set. | | public static double | cosh(double x)
Returns the
hyperbolic cosine of x. | | public static boolean | equals(double x, double y)
| | public static long | factorial(int n)
Returns n!. | | public static double | factorialDouble(int n)
Returns n!. | | public static double | factorialLog(int n)
Returns the natural logarithm of n!. | | public static int | gcd(int u, int v)
Gets the greatest common divisor of the absolute value of two numbers,
using the "binary gcd" method which avoids division and modulo
operations. | | public static int | hash(double value)
Returns an integer hash code representing the given double value. | | public static byte | indicator(byte x)
For a byte value x, this method returns (byte)(+1) if x >= 0 and
(byte)(-1) if x < 0. | | public static double | indicator(double x)
For a double precision value x, this method returns +1.0 if x >= 0 and
-1.0 if x < 0. | | public static float | indicator(float x)
For a float value x, this method returns +1.0F if x >= 0 and -1.0F if x <
0. | | public static int | indicator(int x)
For an int value x, this method returns +1 if x >= 0 and -1 if x < 0. | | public static long | indicator(long x)
For a long value x, this method returns +1L if x >= 0 and -1L if x < 0. | | public static short | indicator(short x)
For a short value x, this method returns (short)(+1) if x >= 0 and
(short)(-1) if x < 0. | | public static int | lcm(int a, int b)
Returns the least common multiple between two integer values.
Parameters:
a - the first integer value.
Parameters:
b - the second integer value. | | public static int | mulAndCheck(int x, int y)
Multiply two integers, checking for overflow. | | public static double | round(double x, int scale)
Round the given value to the specified number of decimal places. | | public static double | round(double x, int scale, int roundingMethod)
Round the given value to the specified number of decimal places. | | public static float | round(float x, int scale)
Round the given value to the specified number of decimal places. | | public static float | round(float x, int scale, int roundingMethod)
Round the given value to the specified number of decimal places. | | public static byte | sign(byte x)
Returns the sign
for byte value x. | | public static double | sign(double x)
Returns the sign
for double precision x. | | public static float | sign(float x)
Returns the sign
for float value x.
For a float value x, this method returns +1.0F if x > 0, 0.0F if x =
0.0F, and -1.0F if x < 0. | | public static int | sign(int x)
Returns the sign
for int value x. | | public static long | sign(long x)
Returns the sign
for long value x. | | public static short | sign(short x)
Returns the sign
for short value x. | | public static double | sinh(double x)
Returns the
hyperbolic sine of x. | | public static int | subAndCheck(int x, int y)
Subtract two integers, checking for overflow. |
| addAndCheck | | public static int addAndCheck(int x, int y)(Code) | | Add two integers, checking for overflow.
Parameters:
x - an addend
Parameters:
y - an addend the sum x+y
throws:
ArithmeticException - if the result can not be represented as anint
since:
1.1 |
| binomialCoefficient | | public static long binomialCoefficient(int n, int k)(Code) | | Returns an exact representation of the Binomial
Coefficient, "n choose k", the number of
k-element subsets that can be selected from an
n-element set.
Preconditions:
-
0 <= k <= n (otherwise
IllegalArgumentException is thrown)
- The result is small enough to fit into a
long. The
largest value of n for which all coefficients are
< Long.MAX_VALUE is 66. If the computed value exceeds
Long.MAX_VALUE an ArithMeticException
is
thrown.
Parameters:
n - the size of the set
Parameters:
k - the size of the subsets to be counted n choose k
throws:
IllegalArgumentException - if preconditions are not met.
throws:
ArithmeticException - if the result is too large to be representedby a long integer. |
| binomialCoefficientDouble | | public static double binomialCoefficientDouble(int n, int k)(Code) | | Returns a double representation of the Binomial
Coefficient, "n choose k", the number of
k-element subsets that can be selected from an
n-element set.
Preconditions:
-
0 <= k <= n (otherwise
IllegalArgumentException is thrown)
- The result is small enough to fit into a
double. The
largest value of n for which all coefficients are <
Double.MAX_VALUE is 1029. If the computed value exceeds Double.MAX_VALUE,
Double.POSITIVE_INFINITY is returned
Parameters:
n - the size of the set
Parameters:
k - the size of the subsets to be counted n choose k
throws:
IllegalArgumentException - if preconditions are not met. |
| binomialCoefficientLog | | public static double binomialCoefficientLog(int n, int k)(Code) | | Returns the natural log of the Binomial
Coefficient, "n choose k", the number of
k-element subsets that can be selected from an
n-element set.
Preconditions:
-
0 <= k <= n (otherwise
IllegalArgumentException is thrown)
Parameters:
n - the size of the set
Parameters:
k - the size of the subsets to be counted n choose k
throws:
IllegalArgumentException - if preconditions are not met. |
| cosh | | public static double cosh(double x)(Code) | | Returns the
hyperbolic cosine of x.
Parameters:
x - double value for which to find the hyperbolic cosine hyperbolic cosine of x |
| equals | | public static boolean equals(double x, double y)(Code) | | Returns true iff both arguments are NaN or neither is NaN and they are
equal
Parameters:
x - first value
Parameters:
y - second value true if the values are equal or both are NaN |
| factorial | | public static long factorial(int n)(Code) | | Returns n!. Shorthand for n Factorial, the
product of the numbers 1,...,n.
Preconditions:
-
n >= 0 (otherwise
IllegalArgumentException is thrown)
- The result is small enough to fit into a
long. The
largest value of n for which n! <
Long.MAX_VALUE is 20. If the computed value exceeds Long.MAX_VALUE
an ArithMeticException is thrown.
Parameters:
n - argument n!
throws:
ArithmeticException - if the result is too large to be representedby a long integer.
throws:
IllegalArgumentException - if n < 0 |
| factorialDouble | | public static double factorialDouble(int n)(Code) | | Returns n!. Shorthand for n Factorial, the
product of the numbers 1,...,n as a double.
Preconditions:
-
n >= 0 (otherwise
IllegalArgumentException is thrown)
- The result is small enough to fit into a
double. The
largest value of n for which n! <
Double.MAX_VALUE is 170. If the computed value exceeds
Double.MAX_VALUE, Double.POSITIVE_INFINITY is returned
Parameters:
n - argument n!
throws:
IllegalArgumentException - if n < 0 |
| factorialLog | | public static double factorialLog(int n)(Code) | | Returns the natural logarithm of n!.
Preconditions:
-
n >= 0 (otherwise
IllegalArgumentException is thrown)
Parameters:
n - argument n!
throws:
IllegalArgumentException - if preconditions are not met. |
| gcd | | public static int gcd(int u, int v)(Code) | |
Gets the greatest common divisor of the absolute value of two numbers,
using the "binary gcd" method which avoids division and modulo
operations. See Knuth 4.5.2 algorithm B. This algorithm is due to Josef
Stein (1961).
Parameters:
u - a non-zero number
Parameters:
v - a non-zero number the greatest common divisor, never zero
since:
1.1 |
| hash | | public static int hash(double value)(Code) | | Returns an integer hash code representing the given double value.
Parameters:
value - the value to be hashed the hash code |
| indicator | | public static byte indicator(byte x)(Code) | | For a byte value x, this method returns (byte)(+1) if x >= 0 and
(byte)(-1) if x < 0.
Parameters:
x - the value, a byte (byte)(+1) or (byte)(-1), depending on the sign of x |
| indicator | | public static double indicator(double x)(Code) | | For a double precision value x, this method returns +1.0 if x >= 0 and
-1.0 if x < 0. Returns NaN if x is
NaN.
Parameters:
x - the value, a double +1.0 or -1.0, depending on the sign of x |
| indicator | | public static float indicator(float x)(Code) | | For a float value x, this method returns +1.0F if x >= 0 and -1.0F if x <
0. Returns NaN if x is NaN.
Parameters:
x - the value, a float +1.0F or -1.0F, depending on the sign of x |
| indicator | | public static int indicator(int x)(Code) | | For an int value x, this method returns +1 if x >= 0 and -1 if x < 0.
Parameters:
x - the value, an int +1 or -1, depending on the sign of x |
| indicator | | public static long indicator(long x)(Code) | | For a long value x, this method returns +1L if x >= 0 and -1L if x < 0.
Parameters:
x - the value, a long +1L or -1L, depending on the sign of x |
| indicator | | public static short indicator(short x)(Code) | | For a short value x, this method returns (short)(+1) if x >= 0 and
(short)(-1) if x < 0.
Parameters:
x - the value, a short (short)(+1) or (short)(-1), depending on the sign of x |
| lcm | | public static int lcm(int a, int b)(Code) | | Returns the least common multiple between two integer values.
Parameters:
a - the first integer value.
Parameters:
b - the second integer value. the least common multiple between a and b.
throws:
ArithmeticException - if the lcm is too large to store as an int
since:
1.1 |
| mulAndCheck | | public static int mulAndCheck(int x, int y)(Code) | | Multiply two integers, checking for overflow.
Parameters:
x - a factor
Parameters:
y - a factor the product x*y
throws:
ArithmeticException - if the result can not be represented as anint
since:
1.1 |
| round | | public static double round(double x, int scale)(Code) | | Round the given value to the specified number of decimal places. The
value is rounded using the
BigDecimal.ROUND_HALF_UP method.
Parameters:
x - the value to round.
Parameters:
scale - the number of digits to the right of the decimal point. the rounded value.
since:
1.1 |
| round | | public static double round(double x, int scale, int roundingMethod)(Code) | | Round the given value to the specified number of decimal places. The
value is rounded using the given method which is any method defined in
BigDecimal .
Parameters:
x - the value to round.
Parameters:
scale - the number of digits to the right of the decimal point.
Parameters:
roundingMethod - the rounding method as defined inBigDecimal. the rounded value.
since:
1.1 |
| round | | public static float round(float x, int scale)(Code) | | Round the given value to the specified number of decimal places. The
value is rounding using the
BigDecimal.ROUND_HALF_UP method.
Parameters:
x - the value to round.
Parameters:
scale - the number of digits to the right of the decimal point. the rounded value.
since:
1.1 |
| round | | public static float round(float x, int scale, int roundingMethod)(Code) | | Round the given value to the specified number of decimal places. The
value is rounded using the given method which is any method defined in
BigDecimal .
Parameters:
x - the value to round.
Parameters:
scale - the number of digits to the right of the decimal point.
Parameters:
roundingMethod - the rounding method as defined inBigDecimal. the rounded value.
since:
1.1 |
| sign | | public static byte sign(byte x)(Code) | | Returns the sign
for byte value x.
For a byte value x, this method returns (byte)(+1) if x > 0, (byte)(0) if
x = 0, and (byte)(-1) if x < 0.
Parameters:
x - the value, a byte (byte)(+1), (byte)(0), or (byte)(-1), depending on the sign of x |
| sign | | public static double sign(double x)(Code) | | Returns the sign
for double precision x.
For a double value x, this method returns
+1.0 if x > 0, 0.0 if
x = 0.0, and -1.0 if x < 0.
Returns NaN if x is NaN.
Parameters:
x - the value, a double +1.0, 0.0, or -1.0, depending on the sign of x |
| sign | | public static float sign(float x)(Code) | | Returns the sign
for float value x.
For a float value x, this method returns +1.0F if x > 0, 0.0F if x =
0.0F, and -1.0F if x < 0. Returns NaN if x
is NaN.
Parameters:
x - the value, a float +1.0F, 0.0F, or -1.0F, depending on the sign of x |
| sign | | public static int sign(int x)(Code) | | Returns the sign
for int value x.
For an int value x, this method returns +1 if x > 0, 0 if x = 0, and -1
if x < 0.
Parameters:
x - the value, an int +1, 0, or -1, depending on the sign of x |
| sign | | public static long sign(long x)(Code) | | Returns the sign
for long value x.
For a long value x, this method returns +1L if x > 0, 0L if x = 0, and
-1L if x < 0.
Parameters:
x - the value, a long +1L, 0L, or -1L, depending on the sign of x |
| sign | | public static short sign(short x)(Code) | | Returns the sign
for short value x.
For a short value x, this method returns (short)(+1) if x > 0, (short)(0)
if x = 0, and (short)(-1) if x < 0.
Parameters:
x - the value, a short (short)(+1), (short)(0), or (short)(-1), depending on the sign ofx |
| sinh | | public static double sinh(double x)(Code) | | Returns the
hyperbolic sine of x.
Parameters:
x - double value for which to find the hyperbolic sine hyperbolic sine of x |
| subAndCheck | | public static int subAndCheck(int x, int y)(Code) | | Subtract two integers, checking for overflow.
Parameters:
x - the minuend
Parameters:
y - the subtrahend the difference x-y
throws:
ArithmeticException - if the result can not be represented as anint
since:
1.1 |
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