Scala - Math log1p() Method

The Scala Math log1p() method returns the natural logarithm of (1 + number), i.e., log(1+number). In special cases it returns the following:

• If the argument is NaN or less than -1, then the result is NaN.
• If the argument is positive infinity, then the result is positive infinity.
• If the argument is negative one, then the result is negative infinity.

Syntax

def log1p(x: Double): Double = java.lang.Math.log1p(x)

Parameters

Return Value

Returns the natural logarithm of (1 + number), i.e., log(1+number).

Exception

NA.

Example:

In the example below, log1p() method is used to calculate the log(1+number).

import scala.math._

object MainObject {
  def main(args: Array[String]) {
    println(s"log1p(E) = ${log1p(E)}");  
    println(s"log1p(E - 1) = ${log1p(E - 1)}"); 
    println(s"log1p(50) = ${log1p(50)}"); 
    println(s"log1p(-1) = ${log1p(-1)}");
    println(s"log1p(Double.NaN) = ${log1p(Double.NaN)}"); 
    println("log1p(Double.PositiveInfinity) = "
            + log1p(Double.PositiveInfinity));
    println("log1p(Double.NegativeInfinity) = "
            + log1p(Double.NegativeInfinity));            
  }
}

The output of the above code will be:

log1p(E) = 1.3132616875182228
log1p(E - 1) = 1.0
log1p(50) = 3.9318256327243257
log1p(-1) = -Infinity
log1p(Double.NaN) = NaN
log1p(Double.PositiveInfinity) = Infinity
log1p(Double.NegativeInfinity) = NaN