4x1 vector to 2x1 vector with S function

Hi,

I have written an Level-2 S-function which creates a 2x1 vector from a 4x1 vector, that it, taking out the first 2 elements.

The function “Output()” is:

function Output(block)
block.OutputPort(1).Data = block.InputPort(1).Data(1:2);

 Error: Attempt to assign a matrix of dimentions [2x1] to a matrix of
 dimensions [4x1].

So I added the following code to the function “Setup()”:

function Setup(block) 
block.OutputPort(1).Dimensions = [2,1];

This time the error is:

 Invalid dimentsion has been specified for input port 1 of …

Now I am helpless with this problem. Who can help me with this problem?

Thanks Senmeis

Answer 1

[Shashank]

Hi,

The reason the error is cropping up is because, while the Output Port Dimensions have been explicitly specified, the S-function is relying on implicit inheritance to determine the dimensions of the Input Port. Due to the differing sizes, there's a conflict. By specifying the InputPort dimensions in this way in the setup method:

block.InputPort(1).Dimensions = 4;

you would be explicitly specifying the Input Port dimensions and the S-function should run fine.