hi i want to calculate nth power for each value of s from 1 to 50 and store the result for each value of s in za varaible

f=imread('lena1.jpg');  
x=rgb2gray(f);
for s=1:50
             za=x.^(s);    
  end

[Guillaume]

Oh! I see the question was edited. s starts as an image, then becomes an iterator. That's confusing! There are 26 letters in the alphabet, you don't have to limit yourself to just 2. Even better, use words for variable names as this makes the intent of the code clearer.

What is the desired output? What size should za be?

Answer 1

[Guillaume]

Sounds like homework to me.

Do you have to use a loop? The normal matlab way is simply:

za = (1:50).^2;

If you do have to use a loop, index your za.

Note that there is a big difference between 2.^x and x.^2. The power operation is not commutative.

[juveria fatima]

i want to power of .^s ,,not .^2 . and s should be ranging from 1 to 50 i.e power

x is our image

like this za = (image).^s;

[Guillaume]

In your question, you wrote "calculate square" which .^2.

What does (image) mean? Perhaps, you should show a numerical example of input and corresponding desired output.

[Guillaume]

Ok, so what do you want as output? Should za be a 3D array of size height(image) x width(image) x 50?

Perhaps, this is what you want:

img = im2double(rgb2gray(imread('lena1.jpg')); 
s = 1:50;
za = img .^ permute(s, [1 3 2]);  %MxNx50 array