Checking if input is square using vectors

Hello, I'm an extreme newbie to MatLab. I'm trying to write a function that checks whether an input is square, and returns 1 for true, 0 for false. I figured that the best way to do this would be to run sqrt on each variable, then use mod to determine whether the remainder is 0. Here's the code I'm trying:

function y = issquare(n) 
x = sqrt(n)
if mod (x,1)==0
    y=true
else
    y=false
end

The problem arises when a vector is input. Instead of returning the answers for individual vectors, it is returning a single answer. The x variable calculates correctly and returns the individual square roots of each value in the vector. The issue seems to arise when the program determines the y variable. I tried changing the mod input to

      mod(x.,1)

but received an error.

Error: File: issquare.m Line: 3 Column: 11
Expression or statement is incorrect--possibly unbalanced (, {, or [.

Answer 1

[Jan]

Appending a dot behind a variable is not valid Matlab syntax. Please look in the documentation for valid commands, because guessing will not be successful.

The problem is, that the if command requires a scalar expression. This can be solved by a vectorized expression:

function y = issquare(n) 
y = (mod(sqrt(n), 1) == 0);

Now the output has the same size as the input.

[thefaded]

I was only trying this because it seems to be the operator for array multiplication, division and exponentiation. I'm really new to programming. I didn't even think about nesting the expression that way. Thank you!

[Jan]

You are welcome to the world of vectorized programming in Matlab!

The dot in ".*", "./" and ".^" means, that the operation should not affect the complete matrix, but the elements. In consequence, there is e.g. no ".+", because the addition concerns the elements in every case.