How to use inside a Simulink file a user-defined class previously written in matlab?

Question

Stefan 2015-6-16

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/224031-how-to-use-inside-a-simulink-file-a-user-defined-class-previously-written-in-matlab

评论： Stefan 2015-6-17

采纳的回答： Sebastian Castro

在 MATLAB Online 中打开

Dear reader,

I have created a simple class given below:

   classdef dummy3
         properties
             a = 0;
             b;
         end
         methods
             %constructor
             function obj = dummy3(a,b)
             % class constructor
                 if(nargin > 0)
                   obj.a = a;
                   obj.b = b;
                 end
             end
         end
         methods(Static = true)            
             function value = roll(numdays)
                 value = numdays;
             end
         end
     end

and let the object P be defined as:

P = dummy3(1,2)

The question is how can I use the variable P.a and how can I call the method P.roll(rand(1)) inside a Simulink file? For convenience, I'd prefer to use them inside a Matlab function, like this scheme:

where I've tried to place inside the code

y = P.a

which resulted in error "Undefined function or variable 'P'." Furthermore, replacing this line by

y = P.roll(rand(1))

yields the same error. I cannot understand why since I did add into File -> Model Properties -> Callbacks -> InitFcn the line of code

P=dummy3(1,2)

Thank you for your help.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Sebastian Castro 2015-6-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/224031-how-to-use-inside-a-simulink-file-a-user-defined-class-previously-written-in-matlab#answer_182897

在 MATLAB Online 中打开

I found 2 main issues here:

First, methods of a class must have the object itself as the first argument. So, to correctly use the roll method, you may want to redefine it as:

function value = roll(obj,numdays)

Secondly, you need to create the object P in your MATLAB Function block. In other words, prior to calling P.roll(4), you should say:

P = dummy3(a,b);
val = P.roll(4);

- Sebastian

3 个评论
显示 1更早的评论隐藏 1更早的评论

Sebastian Castro 2015-6-16

在 MATLAB Online 中打开

Yes -- sorry, I should have mentioned that. You can make P a persistent variable so it is created only on the first execution of the model.

persistent P;
if isempty(P)
P = dummy3(a,b);
end

- Sebastian

Stefan 2015-6-17

Thank you very much for your time. I confirm this is indeed the functionality that I have been looking for. Additionally I have checked that it can be used for code generation purpose.

请先登录，再进行评论。