How can I make an animation out of contourf plots?

Hi,

I am trying to animate my solutions of a 2D convection heat transfer problem over the different time steps using contourf. I would like to make an animation over the time steps to visualize the solution. I have the data for the different time steps in the format T_1.bin, where the number indicates the particular time step.

At the moment I represent the current function (S) and the temperature field (T) of a time step in the following way:

figure(1)
fid = fopen('T.bin');
nx = fread(fid,1,'int32');
ny = fread(fid,1,'int32');
T = reshape(fread(fid,nx*ny,'double'),nx,ny);
fclose = (fid);
contourf(T')

figure(2)
fid = fopen('S.bin');
nx = fread(fid,1,'int32');
ny = fread(fid,1,'int32');
S = reshape(fread(fid,nx*ny,'double'),nx,ny);
fclose = (fid);
contourf(S')

How is the best way to make an animation out of this?

Thanks a lot already in advance for all your help and time.

[David Kaeser]

I tried now to capture the results in gif by modifying the succested code to this:

h = figure;
filename = 'testnew51.gif';
axis tight manual % this ensures that getframe() returns a consistent size
for t=10:10:100  % t is the percent number in the file name
    subplot(121)
    fn = "T_timestep_"+t+"_precent.bin";
    fid = fopen(fn);       % file for t-th step
    nx = fread(fid,1,'int32');
    ny = fread(fid,1,'int32');
    T = reshape(fread(fid,nx*ny,'double'),nx,ny);
    fclose = (fid);
    contourf(T')
    colorbar;
    
    subplot(122)
    fn = "S_timestep_"+t+"_precent.bin";
    fid = fopen(fn);       % file for t-th stepfid = fopen('S.bin');
    nx = fread(fid,1,'int32');
    ny = fread(fid,1,'int32');
    S = reshape(fread(fid,nx*ny,'double'),nx,ny);
    fclose = (fid);
    contourf(S')
    colorbar;
    
    drawnow
    % Capture the plot as an image 
      frame = getframe(h); 
      im = frame2im(frame); 
      [imind,cm] = rgb2ind(im,256); 
      % Write to the GIF File 
      if t == 1 
          imwrite(imind,cm,filename,'gif', 'Loopcount',inf); 
      else 
          imwrite(imind,cm,filename,'gif','WriteMode','append'); 
      end 
    pause(0.2)
end

However I get now the error:

Error using wgifc
Can only append to GIF89a format GIFs.

Error in writegif (line 306)
wgifc(mat, map, filename,writemode,disposalmethod,delaytime,...

Error in imwrite (line 566)
        feval(fmt_s.write, data, map, filename, paramPairs{:});

Error in matlab_run (line 34)
          imwrite(imind,cm,filename,'gif','WriteMode','append');
          

How can I resulve that? Or is there a better way to generate a gif?

Answer 1

[Chunru]

figure
for t=10:10:100  % t is the percent number in the file name
    subplot(121)
    fn = "T_timestep_"+t"_precent";
    fid = fopen(fn);       % file for t-th step
    nx = fread(fid,1,'int32');
    ny = fread(fid,1,'int32');
    T = reshape(fread(fid,nx*ny,'double'),nx,ny);
    fclose = (fid);
    contourf(T')
    
    subplot(122)
    fn = "S_timestep_"+t"_precent";
    fid = fopen(fn);       % file for t-th stepfid = fopen('S.bin');
    nx = fread(fid,1,'int32');
    ny = fread(fid,1,'int32');
    S = reshape(fread(fid,nx*ny,'double'),nx,ny);
    fclose = (fid);
    contourf(S')
    
    drawnow
    pause(0.1)
end

[David Kaeser]

Thank you very much! However it is not quite clear to me yet where I need to change input files. How can I specify them? And also can I do somthing like:

fopen('T_t.bin'); 

Or how is this done?

[Chunru]

Do you have a file for each time step? How the files are named?

[David Kaeser]

YesI have seperatefile for each timestep, sorry for not clarifying it earlier. Currently they are named as follows:

T_timestep_10_precent, T_timestep_20_precent, T_timestep_30_precent, T_timestep_40_precent, T_timestep_50_precent, T_timestep_60_precent, T_timestep_70_precent, T_timestep_80_precent, T_timestep_90_precent, T_timestep_100_precent

S_timestep_10_precent, S_timestep_20_precent, S_timestep_30_precent, S_timestep_40_precent, S_timestep_50_precent, S_timestep_60_precent, S_timestep_70_precent, S_timestep_80_precent, S_timestep_90_precent, S_timestep_100_precent

But I can of course change time in are more convinient manner.

[Chunru]

See the updated above.

[David Kaeser]

Thank you very much!!