Built in Functions¶

There are a number of built-in functions, that usually just map with the corresponding java.util.Math methods (so all of the same restrictions apply), this functions are:

Trigonometric Functions:¶

• sin(x): Sine of an angle expressed in radians
• cos(x): Cosine of an angle expressed in radians
• tan(x): Tangent of an angle expressed in radians

Inverse Trigonometric:¶

• asin(x): Arc sine in the range [-π/2, π/2)
• acos(x): Arc cosine in the range [0, π)
• atan(x): Arc tangent in the range [-π/2, π/2)

Hyperbolic Functions:¶

• sinh(x): Hyperbolic sine (e^x - e^(-x)) / 2
• cosh(x): Hyperbolic cosine (e^x + e^(-x)) / 2
• tanh(x): Hyperbolic tangent (e^x - e^(-x)) / (e^x + e^(-x))

Logarithms¶

• log(x): Base 10 logarithm of x
• log1p(x): Base 10 logarithm of (x + 1)
• log10(x): Base 10 logarithm of x
• log2(x): Base 2 logarithm of x

Misc¶

• pow(b, e): b to the power of e
• sqrt(x): Square root of x
• cbrt(x): Cube root of x
• exp(x): e to the power of x
• expm1(x): e to the power of x minus 1 (e^x - 1)
• signum(x)¹: Signum of x (-1, 0, 1 for < 0, = 0 and > 0 respectively)
• abs(x): Absolute value of x
• ceil(x): First integer closest to negative infinity greater than or equal x
• floor(x): First integer closest to positive infinity less than or equal x

Constants¶

• pi(): Ratio of the circumference of a circle to its diameter 3.14159265358979323846
• e(): Base of the natural logarithm 2.7182818284590452354

Disabling built-in functions¶

Since version 0.6-riddler (commit) you can disable all built-in functions like this:

    Expression e = new ExpressionBuilder("x + 3")
                      .disableBuiltInFunctions() //<--
                      .variable("x")
                      .build();

Remember that since constants are also defined as functions this will also disable them.

Code¶

The code for the functions is here.

¹ This is the only method not implemented using it's corresponding java.util.Math method.