how to find the nearest smallest power of 2 to an integer?

Hello all,

I would like to write a code that finds the nearest smallest power of 2 to integers. For instance, if my integer is 6, its smallest nearest power of 2 is 4, while if the integer is 12, the smallest nearest integer is 8. I would appreciate if somebody can help me please. Thanks.

Answer 1

[Stephen23]

>> N = 6;
>> pow2(floor(log2(N)))
ans =
   4

And it is even fully vectorized code, so you can check all of your values at once:

>> pow2(floor(log2([6,12])))
ans =
   4     8

[Mnr]

Thanks for your answer. Also, I would appreciate if you could tell if I want to have an if else statement in the form of if (N is a power of 2) .... else ... end.

how I can do it?

[Stephen23]

Option Two (more robust):

[X,~] = log2(N);
if X==0.5
    ... code
else
    ... other code
end

Option Two (one line):

if rem(log2(N),1)==0
    ... code
else
    ... other code
end

[Mnr]

Thanks a lot!