Why am I getting invalid file identifier error?

This section of code that I am running keeps giving me the error "Invalid file identifier. Use fopen to generate a valid file identifier" when it gets to the parfor loop. I cannot figure out what would be causing the issue. Where is my file identifier invalid?

if loc1(1)>loc2(1)
    disp('start from flood tide')
    name = {'/home/kward/model/particles/flood/particles_','/home/kward/model/particles/ebb/particles_'};
else
    disp('start from ebb tide')
    name = {'/home/kward/model/particles/ebb/particles_','/home/kward/model/particles/flood/particles_'};
end

loc= unique([loc1,loc2]);
t_r = (t(loc(1:end-1))+t(loc(2:end)))/2;

name1 = name{1};
name2 = name{2};

parfor i=1:length(t_r)
    if mod(i,2) == 1 
        OF = [name1,num2str((i+1)/2,'%02d'),'.dat'];
    else
        OF = [name2,num2str(i/2,'%02d'),'.dat'];
    end
    fprintf('Saving %s\n',OF)
    if (exist(OF, 'file')==2)
        delete(OF);
    end
    fid = fopen(OF,'wt');
    fprintf(fid, [num2str(length(lon)*num),' 2\n']);
    fprintf(fid, 'testing\n');
    fprintf(fid, 'vertical coordinate = zx     y     z    t_release\n');
    fclose(fid);

    tsi = [lon,lat,lat,lat]; % longtitude&latitude
    tsi(:,3) = 0; % depth
    tsi(:,4)=t_r(i);%time
    tsi = repmat(tsi,num,1);
    disp('Writing data...');
    dlmwrite(OF, tsi, 'delimiter', ' ', '-append','precision','%.4f');     
end    

Answer 1

[Sulaymon Eshkabilov]

Hi,

I would check the directory address is correct. And if it is correct, then if MATLAB is reading it correctly.

name = {'/home/kward/model/particles/flood/particles_','/home/kward/model/particles/ebb/particles_'};

Answer 2

[Raymond Norris]

fopen will return two output arguments: the file id and an error message if it failed (i.e., the file id is <0). Add the following for additional diagnostics

[fid, emsg] = fopen(OF,'wt');
if fid<0
    error(emsg)
end