Java - Math scalb(float a, int b) method

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Description

The Java Math scalb(float f,int scaleFactor) returns f x 2^scaleFactor rounded as if performed by a single correctly rounded floating-point multiply to a member of the double value set. See the Java Language Specification for a discussion of floating-point value sets. If the exponent of the result is between Float.MIN_EXPONENT and Float.MAX_EXPONENT, the answer is calculated exactly. If the exponent of the result would be larger than Float.MAX_EXPONENT, an infinity is returned. Note that if the result is subnormal, precision may be lost; that is, when scalb(x, n) is subnormal, scalb(scalb(x, n), -n) may not equal x. When the result is non-NaN, the result has the same sign as f.

• If the first argument is NaN, NaN is returned.

• If the first argument is infinite, then an infinity of the same sign is returned.

• If the first argument is zero, then a zero of the same sign is returned.

Declaration

Following is the declaration for java.lang.Math.scalb() method

public static float scalb(float f, int scaleFactor)

Parameters

• f − number to be scaled by a power of two.

• scaleFactor − power of 2 used to scale d

Return Value

This method returns f x 2^scaleFactor

Exception

NA

Example: Getting scalb for Positive Float Value

The following example shows the usage of Math scalb() method for positive values.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get a float number
      float x = 2.0f;
      int y = 5;
   
      // print x raised by y and then y raised by x
      System.out.println("Math.scalb(" + x + "," + y + ")=" + Math.scalb(x, y));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.scalb(2.0,5)=64.0

Example: Getting scalb for Negative Float Value

The following example shows the usage of Math scalb() method for negative value.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get a float number
      float x = -2.0f;
      int y = 5;
   
      // print x raised by y and then y raised by x
      System.out.println("Math.scalb(" + x + "," + y + ")=" + Math.scalb(x, y));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.scalb(-2.0,5)=-64.0

Example: Getting scalb for Negative Float Value

The following example shows the usage of Math scalb() method for negative scale factor.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get a float number
      float x = 2.0f;
      int y = -5;
   
      // print x raised by y and then y raised by x
      System.out.println("Math.scalb(" + x + "," + y + ")=" + Math.scalb(x, y));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.scalb(2.0,-5)=0.0625