Struct contents reference from a non-struct array object. error in a code

%%clmap.m
clear all
close
load('config.mat')
%number of classes
clmax
%number of trees
mmax
%number of population per class
nmax
%max depth
depthmax
markers=['x','o','.','s','*','d','^','v','>','<'];
colors=[    hex2dec('1f')/255 hex2dec('77')/255 hex2dec('b4')/255;
          hex2dec('ff')/255 hex2dec('7f')/255 hex2dec('0e')/255;
          hex2dec('2c')/255 hex2dec('a0')/255 hex2dec('2c')/255;
          hex2dec('d6')/255 hex2dec('27')/255 hex2dec('28')/255;
          hex2dec('94')/255 hex2dec('67')/255 hex2dec('bd')/255;
          hex2dec('8c')/255 hex2dec('56')/255 hex2dec('4b')/255;
          hex2dec('e3')/255 hex2dec('77')/255 hex2dec('c2')/255;
          hex2dec('7f')/255 hex2dec('7f')/255 hex2dec('7f')/255;
          hex2dec('bc')/255 hex2dec('bd')/255 hex2dec('22')/255;
          hex2dec('17')/255 hex2dec('be')/255 hex2dec('cf')/255];
PQ=zeros(mmax,clmax);
xmax=40;
ymax=40;
%img=ones(ymax,xmax);
img=ones(ymax,xmax,3);
trees=[];
for m=1:mmax
  load(strcat('tree',sprintf('%02d.mat',m)));
  trees= [trees sroot];
end
for i=1:xmax
  for j=1:ymax
      theta=[i/xmax,j/ymax];
      for m=1:mmax
          parent=trees(m);
          %display(strcat('tree',sprintf('%02d ',m)));
          while 1
              if theta(parent.theta)< parent.tau
                  next_parent=parent.BL;
                  %display(sprintf('L '));
              else
                  next_parent=parent.BR;
                  %display(sprintf('R '));
              end
              if isempty(next_parent)
                  PQ(m,:)=parent.PQ;
                  break;
              else
                  parent=next_parent;
              end
          end
      end
      Pout=sum(PQ,1)/mmax;
      %[v index]=max(parent.PQ);
      %img(j,i)=index;
      img(j,i,:)=Pout*colors(1:clmax,:);
  end    
end
%imshow(img,colors,'Border','tight');
imshow(img,'Border','tight');
hold on
load('data.mat');
for i=1:size(data,1)
  plot(data(i,1)*xmax,data(i,2)*ymax, strcat(markers(data(i,3)),'k'));
end
axis xy
..
..
*error is* 
In show (line 26) 
Struct contents reference from a non-struct array object.
Error in show (line 36)
          if theta(parent.theta) < parent.tau

Answer 1

[Guillaume]

Your code is expecting that the sroot variable, which presumably gets popped into existence by your load(strcat('tree',sprintf('%02d.mat',m)));, to be a structure.

As the error message tells you, it is not.

The fix is to either change your code to reflect whatever that sroot is, or change the content of the mat file so that sroot is a structure.

PS: I bet that was a lot of fun copy-pasting these repeated hex2dec()/255. A much easier way to obtain the same thing:

colorshex = ['1f77b4'
             'ff7f0e'
             '2ca02c'
             'd62728'
             '9467bd'
             '8c564b'
             'e377c2'
             '7f7f7f'
             'bcbd22'
             '17becf'];
colors = floor(mod(hex2dec(colorshex) ./ [2^16 2^8 1], 256)) / 255;

[Stephen23]

Another approach:

H = ['1f77b4';'ff7f0e';'2ca02c';'d62728';'9467bd';'8c564b';'e377c2';'7f7f7f';'bcbd22';'17becf'];
M = sscanf(H.','%2x',[3,Inf]).'./255

M = 10×3

0.1216 0.4667 0.7059 1.0000 0.4980 0.0549 0.1725 0.6275 0.1725 0.8392 0.1529 0.1569 0.5804 0.4039 0.7412 0.5490 0.3373 0.2941 0.8902 0.4667 0.7608 0.4980 0.4980 0.4980 0.7373 0.7412 0.1333 0.0902 0.7451 0.8118