Save giving a mistake "Argument must contain a character vector"

I am trying to use the save command to save the end state of two matrix and a variable of my calculation and here is part of the code that is causing the problem

if(save_state==1)

          fprintf('State being saved!\n');
          base_name=save_base;
          base_name=strcat(base_name,'-',int2str(new_nelectrons),'-end-');
          DOS_file=strcat(base_name,'DOS.mat');
          OCC_file=strcat(base_name,'OCC.mat');
          e_file=strcat(base_name,'e_left.txt');
          fprintf('Saving OCC file to name: %s. \n',OCC_file);
          save(OCC_file,'newOccupCOs');
          fprintf('Done!\n');
          fprintf('Saving DOS file to name: %s. \n',DOS_file);
          save(DOS_file,'DOS_new');
          fprintf('Done!\n');
          fprintf('Saving electrons file to name: %s. \n',e_file);
          fprintf(f2,'%d',new_nelectrons);
          fprintf('Done!\n')
          fprintf('Save successful!\n');
  end

And here is the output together with error message:

Saving OCC file to name: test-1782-end-OCC.mat.

Error using save
Argument must contain a character vector.

Error in raMOmovie_forGordon>reconstruct_targets (line 2245)
  save(OCC_file,'newOccupCOs');

Error in raMOmovie_forGordon>raMOmovie_run (line 976)
          [OccupCOs raMOs_H1s DOS_so_far
          nelectrons_left]=reconstruct_targets(filename,templatefile,orblistW,H,
          DOS_so_far, OccupCOs, COs, psi_target,video_file,movie_on,
          nelectrons_left,
          frame_stepsize,E_COlist,DOSparameters,scalefactor,Eshift,save_state,save_base);

Error in raMOmovie_forGordon (line 738)
        raMOmovie_run(filename, templatefile, videofile, nions,
        orblist_bytype, electron_counts, E_Fermi,
        DOSparameters,scriptcodes,scriptfiles,scalefactor,state_loaded,loaded_OccupCOs,loaded_DOS_so_far,loaded_e_left,run_save_state,save_base);

I get that this error message usually means OCC_file is not a string but I think it apparently is in this case? Could anybody help?

[Walter Roberson]

What is class(save_base) ?

[Erdong Lu]

save_base is a string and as shown in the output the OCC_file have content 'test-1782-end-OCC.mat' when using fprintf with %s. So I think this means that the strcat function works properly.

[Walter Roberson]

Is save_base a string() object or is it a character vector? Because if it is a string object then you might just be using a release between the time that strings were introduced (R2016b) and when it became possible to pass a string to save() (which I seem to recall was R2017b, but I would need to cross-check that.)

[Erdong Lu]

Okay. I think that is the problem! Yes, I am using Matlab 2016 and that is really the latest version available to me. save_base is a string object. Emmmmm, is there anyway to deal with it? I tried convertStringsToChars which I found by googling but apparently my version of matlab does not support it.

Answer 1

[Walter Roberson]

base_name = char(save_base);

or

base_name = save_base{1};

[Erdong Lu]

Thank you so much!