Load Variable for Use in Simulink MATLAB Function Block

I have been working on this for a while, but cannot get it to work. Basically, I have a MATLAB function block used in a Simulink model. In this block, I have something along the lines of

persistent a
if isempty(a)
  load a % a is MAT file with 'a' defined in it
end
%use variable a

But that gave an error. So I tried this

persistent a
if isempty(a)
  a = load('a.mat') %a is a structure now
end
%use a.a now

That gave the error: Attempt to extract field 'a' from 'mxArray'.

I'm not sure what to do.

[TAB]

How you are using structure "a" further?

This error will appear probably if you will assign a.a (which is a matlab variable) directly to output.

[Ali]

I use a in numerous MATLAB functions.

sum

mean

bsxfun (I say a = bsxfun(@minus,a,b);)

numel

I also do .^2 on it too.

And in these many functions, i often index into a

i.e. (:,2) or (:,1), etc.

Answer 1

[Kaustubha Govind]

It looks like you are using 'a' like a parameter. Why not declare it as one, so that the value is automatically picked up from the workspace? See Parameter Arguments in MATLAB Function Block Functions. Just remember to not "write" to a. Treat it as read-only.