Simulink: How can I find the where the signal dimensions of a signal are defined?

Hello,

I would like to know if there is a way to find the block/port/... that defines the signal dimensions of other signals 'downstream' (with the -1 setting). I have quite a big model with some large feedback loops and I'm unable to find, in one of these loops, where the signal dimension is set.

Ultimatelly, what I want to do is to convert a vector from a two-dimensional (2-D) signal -[3x1] as specified by simulink- into a one-dimensional (1-D) signal -(3) as specified by simulink-.

I know I can introduce a reshape block, but I would like to trace the origin of the issue if possible.

Thank you.

Answer 1

[Fangjun Jiang]

Select your signal, find its source block where the dimension of this signal is specified as -1. There might be multiple input signals or parameters that could have impact on the dimension of your signal. For example, a 1x1 signal goes through the Gain of [1 2 3] would become a 1x3 signal. You have to trace each of those signals or parameters to find the critical one.

In general, in Simulink, the signal dimenstion of 1x3 and 3x1 are inter-changable but it would be better to define it as [3], instead of [1,3] or[ 3,1], if it is specifically specified somewhere.

[Ernesto Barbazán]

Thank you Fangjun for your answer,

I'm not entirely sure if I explained my self clearly since you say: "find its source block where the dimension of this signal is specified as -1." I mean so because thats how I would prefer to have all blocks defined, with the -1. However, the problem that I have is that somewhere in the model there is a block stating [3x1] that I can not find.

I've been using the 'Highligh signal to source/destination options' and temporarily placing some reshapes to narrow down the search. That way I've found some of these block/ports enforcing the [3x1], yet I have not found all of them. It's worth mentioning that the problem may not be with the 'upstream' blocks/ports but also 'downstream' as shown in the next image:

I was hoping there was some kind of way to find the 'parent' for the signal dimensioning, like maybe looking to some property of a block with those dimesions using the 'get_param' function, or maybe searching for all block/ports in the model with a [3x1] signal (also programatically)

[Fangjun Jiang]

Dimension 3x1 and 3 are not the same in Simulink. Whereever in your model it is specified as 3x1, change it to be 3.