Need help figuring out why this nested function is not working

function [imgstruct,xyzuvwcrm] = IMGHandle(inputArg1)
%UNTITLED2 Summary of this function goes here
%   Detailed explanation goes here
files = inputArg1;
count = 1;
for k = 1:length(files) 
    %[h,d]=svecread(files(k).name)
    varargout = svec2(files(k).name); %Pass files into function to get img struc
%     for i = 1:8
%         table(:,i) = varargout(:,:,i);
%     end 

     %Adds name of file to struct
     xyzuvwcrm(k).name = files(k).name;
     for i = 1:8
         for x = 1:54
             for y = 1:73
                 
                 xyzuvwcrm(k).data(count,i) = varargout(x,y,i); %Read matrix val to table
                 count = count +1; %Counting pixels in the image
             end
         end
         count = 1;
     end 
     
     %Compute the magnitude of u,v,w and insert into column 9 of xyzuvwcrm
     for l = 1:size(xyzuvwcrm(k).data,1)
         
         xyzuvwcrm(k).data(l,9) = sqrt(sum((xyzuvwcrm(k).data(l,4:6)).^2));
     end 
     
     %Creates the Image pixel structure
     xyzuvwcrm(k).data = array2table(xyzuvwcrm(k).data,...
         'VariableNames',["x mm","y mm","z mm","u m/s","v m/s","w m/s",...
         "CHC","R Err","Magnitude"]);
     imgstruct(k).name = files(k).name; 
     imgstruct(k).data = varargout ;%(:,:,i)
end
    function varargout = svec2(varargin)

        msg = nargchk(1,3,nargin); if ~isempty(msg), error(msg), end;
        % Defaults:
        if nargin < 3
            varargin{3} = 8;		% default columns value   (13/08/01)
            if nargin < 2
                varargin{2} = 1;	% default number of header lins
            end
        end

        % Assign variables
        name = varargin{1};
        % append an extension if the user neglected to include it

        headerlines = 1;
        columns = 8;
        % this seems like it would cause as many problems as it might fix.
        if isempty(strfind(lower(name),'.v3d'))
            name = strcat(name,'.v3D');
        end
        % Read the header
        fid = fopen(name,'r');
        if fid<0
            error('File not found');
        end
        hdr = fgetl(fid);
        fclose(fid);
        % Parse the header
        % i'm terrible at using regex safely,
        % so take this with a grain of salt
        hdr = lower(hdr);
        i = regexp(hdr,'i=(\d+)','tokens');
        i = str2double(i{1}{1});
        j = regexp(hdr,'j=(\d+)','tokens');
        j = str2double(j{1}{1});
        k = regexp(hdr,'k=(\d+)','tokens');
        k = str2double(k{1}{1});
        % read everything using a convenience tool
        data = readmatrix(name,'filetype','text', ...
            'expectednumvariables',columns, ...
            'numheaderlines',headerlines);
        badind = find(data>9e9);
        if ~isempty(badind), data(badind) = 0; warning(sprintf('Bad %d points',length(badind))); end;
        % then reshape
        % i don't know which way this is supposed to be oriented
        data = reshape(data,i,j,[]);
        data = permute(data,[2 1 3]);
        if nargout == 1
            varargout{1} = data;
        elseif nargout == 2
            varargout{1} = hdr;
            varargout{2} = data;
        elseif nargout == 4
            varargout{1} = hdr;
            varargout{2} = data;
            varargout{3} = str2num(i);
            varargout{4} = str2num(j);
            varargout{5} = str2num(k);
        else
            warning('Wrong number of outputs') ;
        end
    end
    
end

As you can see from the function above IMGHandle is the main function which uses the function svec2 defined within it. I have made sure that all files are within the same folder and this is the current folder. Have restarted matlab to try to update cache etc.

Currently the output I am getting when trying to pass a struct into IMGHandle is the following:

Error using pivdatareadertest>IMGHandle/svec2

File not found

Error in pivdatareadertest>IMGHandle (line 254)

varargout = svec2(files(k).name); %Pass files into function to get img struc

Error in pivdatareadertest (line 55)

[imgstruct,xyzuvwcrm] = IMGHandle(Class4FS20HZ);

Thank you.

Answer 1

[Stephen23]

"File not found"

You are not providing FOPEN and READMATRIX with the filepath, so they cannot find the file on your computer. Presuming that INPUTARG1 is actually the structure returned from DIR, then you should replace

svec2(files(k).name);

with

svec2(fullfile(files(k).folder,files(k).name));

Note that your use of VARARGOUT when calling SVEC2 is not a cell array of function output arrays (of the function IMGHANDLE). To avoid confusion (e.g. your own) you should rename it to e.g. DATA.

As far as I can tell you are not accessing any variables directly from the parent workspace, so nesting the function SVEC2 serves no purpose. It might as well be a simple local function.

[Jensen Lam]

Thank you. This seemed to have work.

You are also correct. varargout is actually a 54x73x8 double. It is used within IMGHandle to create imgstruct (struct) and xyzuvwcrm (also a struct). When I am now calling this however it tells me that

"Right hand side of an assignment into a table must be another table or a cell array."

Any idea why this is occuring? The function IMGHandle should return 2 structs and I also tried swapping the "[ ]" for curly brackets.

For example I would call it like this: [imgstruct,xyzuvwcrm] = IMGHandle(Class4FS20HZ);

where Class4FS20HZ is an input struct

[Stephen23]

"Any idea why this is occuring?"

Please show the complete error message. This means all of the red text.

Removing useful information from the error message makes it harder for people to help you debug your code.

[Jensen Lam]

pivdatareadertest is a simple script that just feeds 100x1 sized structs into the function.

Here is the full error shown:

Error using pivdatareadertest>IMGHandle

Right hand side of an assignment into a table must be another table or a cell array.

Error in pivdatareadertest (line 55)

[imgstruct,xyzuvwcrm] = IMGHandle(Class4FS20HZ);

[Stephen23]

"Here is the full error shown"

Odd, it seems to be missing the actual line throwing the error. In lieu of that, you should set a breakpoint on that line where the error occurs (or use DBSTOP IF ERROR), then check the classes of the array being assigned & indexed.

[Jensen Lam]

I tried to make it simpler by just combining the two structs into one where xyzuvwcrm is now just imgstruct.vel (velocity data). And so it outputs only imgstruct. Set a breakpoint and the result of imgstruct is a name field with the name of each file within the input struct, the velocity (vel) data as a table, and the 54x73x8 double.

However, using break points, it seems like the error really happens at this line:

xyzuvwcrm(k).data(count,i) = varargout(x,y,i); %Read matrix val to table

Edit: it seems to be only throwing the error only when its completing constructing the table as well

it seems that :

svec2(fullfile(files(k).folder,files(k).name));

somehow is keeping the incrementing k value stuck at 1 somehow.

[Jensen Lam]

I changed k within IMGHandle to n since svec2 has an k value already. That worked. Thanks