how to use syms variables in function?

i wrote a function for matrix:

%=============================

function [A] = Test(a,b)

A(1,1)=a+1;

A(1,2)=b;

end

%=======================

the function is nothing special. when i input in Command Window area of Matlab:

>> syms a b

>> Test(0,b)

but Matlab shows:

The following error occurred converting from sym to double: DOUBLE cannot convert the input expression into a double array. Error in Test (line 3) A(1,2)=b;

Matlab tell me there is a mistake(my Expect to return: A=[1,b])

how to fix this problem,thank you very much!

Answer 1

[Star Strider]

In order to do that, you will have to convert ‘A’ to a symbolic object as well:

function [A] = Test(a,b)
    A = sym('A',[1 2])
    A(1,1)=a+1;
    A(1,2)=b;
end

then:

Q = Test(0,b)
Q =
[ 1, b]