Masked Subsystem: How to pass a double vector to a constant?

This is a slightly long-winded problem, but should be easy to follow along.

End goal : Input a 'double' vector into a C++ S Function by assigning it to a Constant.

Starting point: A function within the Dialog Callback of my masked subsystem returns the double vector that I need.

Steps in the middle: So I have a double vector as an input, I need a double vector as an output, but I cannot pass the vector directly, because set_param requires that I pass the value as a string.

Problem: What I tried is this:

set_param(gcb,'refNameArray',num2str(refName));

where,

• gcb (correctly) returns the block from within which I am doing everything.
• refNameArray is the parameter which needs to be assigned the double vector
• refName is the vector, in 'double' form, that I have available within the dialog callback of the mask.

I use num2str because I cannot directly assign a vector, I must input it as a string. But, even using num2str, I get an error saying

Invalid Setting in Block <blockName> for parameter 'Value'.

Any suggestions?

Answer 1

[Yao Li]

I'm not quite sure about your issue. In general, if you want to assign a value to a parameter in a masked subsystem, add it as a parameter in the Mask Editor as shown in the following link

http://www.mathworks.com/help/simulink/gui/parameters-pane.html

and then assign the value by

refNameArray=refName;

In case you do need to convert the value to a string first, try converting the array to a cell and converting it back to a double type array by the command sprintf()

[Kaustubha Govind]

I agree. You may to test what num2str(refName) returns to see why that may be resulting an error.

Answer 2

[Fangjun Jiang]

I don't know why this old question suddenly appears at the top.

I believe the answer to this question is a trick. Use mat2str(), instead of num2str(). So when evaluated, the string will return an array.

a=1:3

a = 1×3

1 2 3

b=num2str(a)

b = '1  2  3'

c=mat2str(a)

c = '[1 2 3]'

eval(c) 

ans = 1×3

1 2 3

eval(b)

Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.