Rules can contain any of the inbuilt mathematical functions listed in the table below:
| Name | Description |
| abs | Returns the absolute value of a number |
| ceil | Returns the smallest integer greater than or equal to the argument |
| floor | Returns the largest integer less than or equal to the argument |
| log | Returns the logarithm of a number |
| log10 | Returns the base 10 logarithm of a number |
| max | Returns the larger of two numbers |
| min | Returns the smaller of two numbers |
| pow | Returns the result of raising one number to the power of another number |
| round | Returns a number rounded to the nearest integer |
| sign | Returns a value indicating the sign of a number |
| sqrt | Returns the square root of a number |
Returns the absolute value of a number.
Signature
double abs(double x)
Parameters
x : The number to return the absolute value of.
Returns
If x is not negative it returns x. If x is negative it returns the negation of x. If x is zero it returns zero.
Examples
abs(1) = 1 abs(0) = 0 abs(-1) = 1
Returns the smallest integer greater than or equal to the argument.
Signature
double ceil(double x)
Parameters
x : The number to round.
Returns
The smallest integer greater than or equal to x. This is sometimes called rounding towards positive infinity.
Examples
ceil(1.6) = 2 ceil(1.5) = 2 ceil(1.4) = 2 ceil(1) = 1 ceil(0) = 0 ceil(-1) = -1 ceil(-1.4) = -1 ceil(-1.5) = -1 ceil(-1.6) = -1
Returns the largest integer less than or equal to the argument.
Signature
double floor(double x)
Parameters
x : The number to round.
Returns
The largest integer less than or equal to x. This is sometimes called rounding towards negative infinity.
Examples
floor(1.6) = 1 floor(1.5) = 1 floor(1.4) = 1 floor(1) = 1 floor(0) = 0 floor(-1) = -1 floor(-1.4) = -2 floor(-1.5) = -2 floor(-1.6) = -2
Returns the natural (base e) logarithm of a number.
Signature
double log(double x)
Parameters
x : The number whose logarithm is to be returned.
Returns
The natural (base e) logarithm of x. If x is zero or negative then zero is returned.
Examples
log(1000) = 6.90775527898214 log(100) = 4.60517018598809 log(10) = 2.30258509299405 log(1) = 0 log(0.1) = -2.30258509299405
Returns the base 10 logarithm of a number.
Signature
double log10(double x)
Parameters
x : The number whose logarithm is to be returned.
Returns
The base 10 logarithm of x. If x is zero or negative then zero is returned.
Examples
log10(1000) = 3 log10(100) = 2 log10(10) = 1 log10(1) = 0 log10(0.1) = -1
Returns the larger of two numbers.
Signature
double max(double x, double y)
Parameters
x : The first of the two numbers to be compared.
y : The second of the two numbers to be compared.
Returns
The larger of the two numbers x and y. If x and y are equal then the same number is returned.
Examples
max(1, 0) = 1 max(0, -1) = 0 max(-1.3, -3.5) = -1.3
Returns the smaller of two numbers.
Signature
double min(double x, double y)
Parameters
x : The first of the two numbers to be compared.
y : The second of the two numbers to be compared.
Returns
The smaller of the two numbers x and y. If x and y are equal then the same number is returned.
Examples
min(1, 0) = 0 min(0, -1) = -1 min(-1.3, -3.5) = -3.5
Returns the result of raising one number to the power of another number.
Signature
double pow(double x, double y)
Parameters
x : A number to be raised to a power.
y : The power to raise x to.
Returns
x raised to the power y. If the result is positive infinity (e.g. x = 0 and y < 0) or not a number (e.g. x < 0 and y is not an integer) then zero is returned.
Examples
pow(2, 3) = 8 pow(100, 2) = 10000
Returns a number rounded to the nearest integer.
Signature
double round(double x)
Parameters
x : The number to round.
Returns
The integer nearest to x. If x is exactly halfway between two integers then it is rounded to the integer that is further from zero.
Examples
round(1.6) = 2 round(1.5) = 2 round(1.4) = 1 round(1) = 1 round(0) = 0 round(-1) = -1 round(-1.4) = -1 round(-1.5) = -2 round(-1.6) = -2
Returns a value indicating the sign of a number.
Signature
double sign(double x)
Parameters
x : The number to determine the sign of.
Returns
-1 if x is less than zero.
0 if x is equal to zero.
1 if x is greater than zero.
Examples
sign(10) = 1 sign(0) = 0 sign(-10) = -1
Returns the square root of a number.
Signature
double sqrt(double x)
Parameters
x : The number to square root.
Returns
The positive square root of x. If x is negative then zero is returned.
Examples
sqrt(64) = 8 sqrt(2) = 1.4142135623731 sqrt(0) = 0