IsPowerOfTwo {wavethresh} | R Documentation

## Decides whether vector elements are integral powers of two (returns NA if not).

### Description

This function checks to see whether its input is a power of two. If it is then it returns that power otherwise it returns NA.

### Usage

    IsPowerOfTwo(n)

### Arguments

`n` | Vector of numbers that are to be checked whether it is a power of two.

### Details

Function takes the log of the input, divides this by log(2) and if the result is integral then it knows the input is true power of two.

### Value

If `n` is a power of two, then the power is returned otherwise `NA` is returned.

### RELEASE

Version 3.6.0 Copyright Guy Nason 1995

### See Also

`nlevels.default`.

### Examples

    #
    # Try and see whether 1,2,3 or 4 are powers of two!
    #
    #IsPowerOfTwo(1:4)
    # [1]  0  1 NA  2
    #
    # Yes, 1,2 and 4 are the 0, 1 and 2nd power of 2. However, 3 is not an
    # integral power of two.

[Package wavethresh version 4.0-2 Index]