How can I change the dimension of a global variable?

I want to define a global variable:

global v
v=[1 2]

but I have this error: Size mismatch (size [1 x 1] ~= size [2 x 1]). The size to the left is the size of the left-hand side of the assignment. How can I change the dimension of v? In the data store memory?

[James Tursa]

Is this in Simulink?

[alessandro]

Yes, in Simulink

[alessandro]

Do you know how can I solve it?

[José-Luis]

Duplicate question.

Alessandro, if you want better answers, I would suggest you provide better feedback to the people that are trying to help you, instead of basically asking the same question again.

[alessandro]

Sorry but I have to complete this work today and I'm looking for any help

[José-Luis]

Why your question is not urgent.

Also, you would make it easier for people to help you if you:

1. Provide more details
2. Give a minimum working example reproducing the problem you face. Often, by doing that, you will find the answer yourself.
3. Provide feedback to the people that try to help you.

What is the data store memory? Have you tried the debugger?

[alessandro]

ok, I try to explain with more details. I have to simulate an inverter modulation in simulink. In the image I show which blocks I've used. Inside the Matlab function there is the code. In this code I've to define a global variable, so I used a Data Store Memory(Help Matlab) like in the second image. In the code I just define a funcion like:

   global v
    v=[1 2]

but didn't work. I have this error: Size mismatch (size [1 x 1] ~= size [2 x 1]). The size to the left is the size of the left-hand side of the assignment. So I want to change the dimension of the global variable.

Answer 1

[Star Strider]

I cannot reproduce the error in R2014a. It works even if I assign v before I declare it as a global. However this:

v = pi

global v

v = [1 2]

throws this warning:

Warning: The value of local variables may have been changed to match the globals.  Future versions of MATLAB will
require that you declare a variable to be global before you use that variable.

What version are you using?

[alessandro]

Ah, I'm using the R2012a