StrictMath log1p() Method in Java
Last Updated :
08 Sep, 2021
The java.lang.StrictMath.log1p() is an in-built method in Java which is used to accept a double value as argument and returns the natural logarithm of the sum of the argument and 1.
Syntax:
public static double log1p(double x)
Parameters: The function accepts a double value x as parameter and calculates the natural algorithm of (1+x).
Return Values: This method returns the value ln(1+x). The result of log1p(x) is almost as close as the actual result of ln(1 + x) for small values x than the floating-point evaluation of log(1.0+x).
Following cases are considered :
- The function returns positive infinity if the argument is positive infinity.
- The function returns negative infinity for negative infinity.
- The function returns NaN if the argument is NaN or less than -1.
- The function returns zero with the sign same as that of the argument if the argument is zero.
Examples:
Input : 2018.0
Output : 7.610357618312838
Input : -4743.0
Output : NaN
Below programs illustrate the working of java.lang.StrictMath.log1p() function:
Program 1: In this program, finite and non-zero argument is passed.
Java
import java.io.*;
import java.lang.*;
class GFG {
public static void main(String[] args)
{
double val1 = 2018.00567 , val2 = 99999.0 ;
System.out.println( "Natural Logarithm of " +
(val1 + 1 ) + " is " + StrictMath.log1p(val1));
System.out.println( "Natural Logarithm of " +
(val2 + 1 ) + " is " + StrictMath.log1p(val2));
}
}
|
Output:
Natural Logarithm of 2019.00567 is 7.610360426629845
Natural Logarithm of 100000.0 is 11.512925464970229
Program 2: In this program, infinite and negative arguments are passed.
Java
import java.io.*;
import java.lang.*;
class GFG {
public static void main(String[] args)
{
double val1 = 201800 / ( 0.0 ), val2 = - 4743.0 ;
System.out.println( "Natural Logarithm of " +
(val1 + 1 ) + " is " + StrictMath.log1p(val1));
System.out.println( "Natural Logarithm of " +
(val2 + 1 ) + " is " + StrictMath.log1p(val2));
}
}
|
Output:
Natural Logarithm of Infinity is Infinity
Natural Logarithm of -4742.0 is NaN
Reference: https://docs.oracle.com/javase/8/docs/api/java/lang/StrictMath.html#log1p()
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