code works as part of main script but not as a function?

I want to make the parameter script of my simulation more orginsed und desided to some of its part as function. But the same code as function is not working.

the function, which I written is:

function y_fast=FAST_Power_Value(y_FAST)

if exist ('y_FAST.mat','file')
    % function to load y_FAST.mat and create y_fast.mat with specified varaibles.  
    load('y_FAST.mat');
    
    c = {'Time','GenPwr','GenTq','U','Upu','GenPwrpu'};
    
    row = length(y_FAST{1,1}.OutData);
    col = length(c);
    j=1;
    y_fast = struct([]);
    
    for i = 1:length(y_FAST)
        y_fast{i,1} = y_FAST{i,1};
        
        for index = 1:length(y_FAST{i}.OutList)
            
            if ~ismember(y_fast{i}.OutList(index),c)==1                                      % to replace cell's contain in the OutList with NaN if they are not member of c vector
                
                y_fast{i,1}.OutList{index}='NaN';
            end
            
            if  strcmp(y_fast{i,1}.OutList{index},'NaN')==0
                y_fast{i,1}.Outdata(:,j) = y_fast{i,1}.OutData(:,index);                     % to copy the data of the nan cells in OutList to a new variable Outdata
                j=j+1;
            end
        end
        
        y_fast{i,1}.OutList = y_fast{i,1}.OutList(~strcmp(y_fast{i,1}.OutList,'NaN'));       % To remove 'NaN' from OutList
        y_fast{i,1}.OutData = y_fast{i,1}.Outdata;
        j=1;
    end
    y_fast=cellfun(@(x)rmfield(x,'Outdata'),y_fast,'UniformOutput',0);                       % To remove Outdata field from structure
    clear y_FAST row col c j index i;
end
end

and I called it in the main script using the command:

y_fast=FAST_Power_Value(y_FAST);

but gives the following errors

Unrecognized function or variable

'y_FAST'.

Error in para_sim_fl_par_com_update

(line 13)

y_fast=FAST_Power_Value(y_FAST);

althogh the y_FAST.mat exist in current folder.

Answer 1

[KSSV]

y_FAST = 'myfile.mat' ;    % give your file name here 
y_fast=FAST_Power_Value(y_FAST) ; 

And use this function:

function y_fast=FAST_Power_Value(y_FAST)

if exist (y_FAST,'file')
    % function to load y_FAST.mat and create y_fast.mat with specified varaibles.  
    load(y_FAST);
    
    c = {'Time','GenPwr','GenTq','U','Upu','GenPwrpu'};
    
    row = length(y_FAST{1,1}.OutData);
    col = length(c);
    j=1;
    y_fast = struct([]);
    
    for i = 1:length(y_FAST)
        y_fast{i,1} = y_FAST{i,1};
        
        for index = 1:length(y_FAST{i}.OutList)
            
            if ~ismember(y_fast{i}.OutList(index),c)==1                                      % to replace cell's contain in the OutList with NaN if they are not member of c vector
                
                y_fast{i,1}.OutList{index}='NaN';
            end
            
            if  strcmp(y_fast{i,1}.OutList{index},'NaN')==0
                y_fast{i,1}.Outdata(:,j) = y_fast{i,1}.OutData(:,index);                     % to copy the data of the nan cells in OutList to a new variable Outdata
                j=j+1;
            end
        end
        
        y_fast{i,1}.OutList = y_fast{i,1}.OutList(~strcmp(y_fast{i,1}.OutList,'NaN'));       % To remove 'NaN' from OutList
        y_fast{i,1}.OutData = y_fast{i,1}.Outdata;
        j=1;
    end
    y_fast=cellfun(@(x)rmfield(x,'Outdata'),y_fast,'UniformOutput',0);                       % To remove Outdata field from structure
    clear y_FAST row col c j index i;
end
end

[Laila Rezai]

Thank you very much KSSV. It works now :)