Simulink Subsystem False Results

The script isnt the project but rather a simple code for the sake of the doubt. This Script should be used to design a Mask that changes the number of blocks (Gain blocks) depending on the input value given from the user. The script should only construct an Input port (R) and multiple of Gain blocks which will all be connected automatically together. This script is inserted under "Mask Editor -> Code" as Gain(gcb)

Problem:

1- The Gain blocks are not generated, rather series of lines named Gain. (see picture)

2- How to assign gain value for all the Gain blocks (should be entered by the user in the Mask)

The Code:

function Gain(sys)

    N = max([1 round(str2double(get_param(sys,'N')))]);
    
    % clear out any old, unneeded circuitry
    lines = find_system(sys,'SearchDepth','1','LookUnderMasks','On','FindAll','On','Type','Line');
    delete(lines);
    blks = find_system(sys,'SearchDepth','1','LookUnderMasks','On','BlockType','Gain');
    delete_block(blks);
    
    % change in position between blocks
    blockIncrement = [40 0];
    
    % calculate all of the required block positions
    blockPosition = zeros(N,4);
    blockPosition(1,1:2) = [305 23];
    blockPosition(1,3:4) = blockPosition(1,1:2);
    loopIncr = 1;
    
    for ii = 2:loopIncr:size(blockPosition,1)
         blockPosition(ii,1:2) = blockPosition(ii-1,[3 2])+blockIncrement;
         blockPosition(ii,3:4) = blockPosition(ii,1:2);
    end
    
    % add the blocks
    cblk = 1;
    for ii = 1:loopIncr:size(blockPosition,1)
        h = add_block('simulink/Math Operations/Gain',[sys '/Gain' num2str(cblk)],'Position',blockPosition(ii,:));
        set(h,'NamePlacement','Alternate');
        set_param(h,'K','N');
        cblk = cblk+1;
    end
    
    % connect Connectors to Cable
    add_line(sys,'R/1','Gain1/1','autorouting','on');
    
    % connect Cable segments together
    for ii = 2:loopIncr:size(blockPosition,1)
            add_line(sys,['Gain' num2str(ii-1) '/1'],['Gain' num2str(ii) '/1'],'autorouting','on'); 
    end
end

Answer 1

[Daniel]

It's creating gain blocks for you. But they all have a size of 0 wide/0 tall, so they're invisible. See how Position is defined in https://www.mathworks.com/help/releases/R2023a/simulink/slref/common-block-parameters.html.

You should be able to pass the gain in as a name/value pair, same as position. So when you call add_block, add a parameter pair 'Gain',gainValue. Note that gainValue should not be a number: it has to be a string which evaluates to a number. In the mask definition, you might want to disable evaluation on the value the user provides for gain. That should preserve it as a string, I think.

[Ahmed Ellithy]

Took a while to implement what you said, but at the end you were right! The blocks were there but, as said, so small to be visible. It was solved by adding an extra argument to blockPosition(ii,3:4).