matlab function in simulink

Hi everyone

In the Simulink environment, I encountered a problem that I want to create a discrete viewer using the MATLAB function and I did this with the for-loop. The problem is that function inputs, which are discrete signals, are not arrays and will be 1 by 1. Someone can help me?

function wr = fcn(ia,ib,va,vb)

I=[1 0;0 1];

J=[0 -1;1 0];

i_a=1;

i_b=0;

psi_a=1;

psi_b=0;

wr0=0;

for i=1:length(ia)

wr=wr0+0.2*(i_a - ia(i))*psi_a;

[i_a;i_b;psi_a;psi_b] == [I+0.1 0.5*I+0.9*wr;J+1*I J*wr+0.2*I]*[i_a;i_b;psi_a;psi_b] ...

+[I*800;0*I]*[va(i);vb(i)] - [2*I-1*J;wr*I-0.2*J]*[ia(i);ib(i)];

wr0 = wr;

end

[Walter Roberson]

What is that == doing there? You cannot do multiple assignments using that approach.

Also it looks like after the == you have a 2x2 array * a 4x1 array, which would be a dimension mismatch.

[Mirzakhani]

I have a 4*4 array.let me explain on paper.I'm implementing a Leuenberger observer in Simulink using matlab function.

[Mirzakhani]

How can we do multiple assignments in simulink ?

Answer 1

[Walter Roberson]

You are in a MATLAB Function Block, so you need to follow MATLAB syntax.

MATLAB does not have multiple assignment in the form

[list] Operator [list]

In order to do multiple assignment in MATLAB you need one of these forms:

1)

[list] = deal(expression, expression,...)

deal is really just a function that returns multiple outputs, copying each input to its corresponding output. Example

[a, b] = deal(3,5)

2) cell expansion

[list] = somecell{:}

example

t = {3,5} 
[a, b] = t{:}

3) structure expansion

[list] = Some_struct.fieldname

example

t(1).x=3;
t(2).x=5;
[a, b] =  t.x

When you have a list of values of fixed size, in my opinion you should just use straight forward individual assignments: the alternatives just make the code less clear and less efficient.