Dynamically change the number of ports of a block

Hello everyone,

I'm looking for a way to build a Simulink block, where the number of port is defined by the user, e.g. a mask allows the user to define by using a popup the number of input port of the block.

Is there any way to do that ? I know I can define inside a s-function the number of ports

%%Register number of input and output ports
block.NumInputPorts  = 1;
block.NumOutputPorts = 1;

but is that the only solution available?

thanks a lot

[grapevine]

because an image is worth thousand words

take a look at that

http://blogs.mathworks.com/seth/2008/08/13/dynamic-mask-dialogs/#comment-1732

how do they dynamically update the number of input?

do They pass a parameter to a sfunction or not?

[grapevine]

I guess they use this instruction

replace_block(gcs,'Inport','Ground','noprompt' );

right guess?

Answer 1

[Kaustubha Govind]

Have you tried setting the number of input ports based on the parameter value? For example, try something like:

 block.NumInputPorts = block.DialogPrm(3).Data;

[grapevine]

Thanks for the advice, I'll try but actually I have to write a L2 S-function with C I'm wondering if I can use the same instructions, same structure like Block, or I have to replace the structure Block with SimStruct *S.

[grapevine]

I made it, here is the code :

"

% Register number of parameters

block.NumDialogPrms = 1;

% Register number of input and output ports

block.NumInputPorts = block.DialogPrm(1).Data;

block.NumOutputPorts = 1;

"

but this solution involves a L2 mfile sfucntion and I need to write a L2 C file sfunction

Any suggestion to do that, will be very appreciated

[Kaustubha Govind]

Not sure, but you could try extending the same logic to C S-functions by using similar code in mdlInitializeSizes.

const mxArray* prm1 = ssGetSFcnParam(S, 0);

int_T nInputPorts = (int_T)(mxGetPr(prm1)[0]); //assuming param is a double value

if (!ssSetNumInputPorts(S,nInputPorts)) return;