please help! how can i solve the error 'Assignment has more non-singleton rhs dimensions than non-singleton subscripts"

I replaced the original code with the data input of the problem as below:( i will attach the file) and i get the problem and i dont know what to do because this is my first time in using matlab to solve problem. i think the problem is when i replace the the "m(i,j)=randint(1,1,9);" with the data input(30x30 matrix).please help me, thank you!

clc;
clear all;
disp('DIJKISTRA ALGORITHM');
n=input('Enter the no. of nodes: ');

for i=1:n
    %initialize
    for j=i:n       
        if(i==j)
    m(i,j)=0;
        else
            m(1,j)=[0  39  22  59  54  33  57  32  89  73  29  46  16  83  120  45  24  32  36  25  38  16  43  21  50  57  46  72  121  73;
                    39  0  20  20  81  8  49  64  63  84  10  61  25  49  81  81  58  16  72  60  78  24  69  18  75  88  68  44  83  52;
                    22  20  0  39  74  18  60  44  71  73  11  46  6  61  99  61  37  10  51  40  59  5  62  7  57  78  51  51  100  56;
                    59  20  39  0  93  27  51  81  48  80  30  69  45  32  61  97  75  31  89  78  97  44  83  38  84  100  77  31  63  42;
                    54  81  74  93  0  73  43  56  104  76  76  77  69  111  72  46  56  84  49  53  33  69  12  69  64  7  69  122  73  114;
                    33  8  18  27  73  0  45  61  71  88  8  63  22  57  87  77  54  18  68  56  71  20  61  13  75  80  68  52  90  60;
                    57  49  60  51  43  45  0  85  88  115  52  103  60  75  64  85  79  63  83  78  70  58  38  52  103  49  102  81  69  92;
                    32  64  44  81  56  61  85  0  74  43  55  23  40  81  97  17  8  50  8  7  23  41  53  48  19  53  17  70  92  63;
                    89  63  71  48  104  71  88  74  0  38  69  51  75  16  35  75  77  61  77  80  90  76  116  76  58  98  57  19  33  16;
                    73  84  73  80  76  88  115  43  38  0  81  28  72  53  55  38  49  70  42  50  53  75  83  80  24  69  27  49  51  39;
                    29  10  11  30  76  8  52  55  69  81  0  55  16  57  91  71  48  11  62  50  68  14  64  9  67  81  61  49  93  56;
                    46  61  46  69  77  63  103  23  51  28  55  0  44  59  81  32  26  46  29  29  45  47  76  53  15  73  9  49  77  40;
                    16  25  6  45  69  22  60  40  75  72  16  44  0  67  105  56  33  16  46  35  53  2  57  9  54  72  48  57  106  60;
                    83  49  61  32  111  57  75  81  16  53  57  59  67  0  39  88  82  51  87  85  103  67  113  65  70  109  67  12  39  19;
                    120  81  99  61  72  87  64  97  35  55  91  81  105  39  0  84  104  90  93  104  90  104  82  99  79  70  82  50  4  51;
                    45  81  61  97  46  77  85  17  75  38  71  32  56  88  84  0  23  67  9  21  15  57  48  64  19  41  23  80  81  70;
                    24  58  37  75  56  54  79  8  77  49  48  26  33  82  104  23  0  44  14  3  25  34  51  41  25  54  23  70  100  65;
                    32  16  10  31  84  18  63  50  61  70  11  46  16  51  90  57  44  0  58  47  67  16  72  15  59  88  52  42  90  47;
                    36  72  51  89  49  68  83  8  77  42  62  29  46  87  93  9  14  58  0  12  16  48  48  55  19  45  21  77  89  69;
                    25  60  40  78  53  56  78  7  80  50  50  29  35  85  104  21  3  47  12  0  22  36  48  43  26  51  24  73  100  68;
                    38  78  59  97  33  71  70  23  90  53  68  45  53  103  90  15  25  67  16  22  0  54  33  59  33  31  37  93  88  84;
                    16  24  5  44  69  20  58  41  76  75  14  47  2  67  104  57  34  16  48  36  54  0  57  7  56  72  50  57  105  61;
                    43  69  62  83  12  61  38  53  116  83  64  76  57  113  82  48  51  72  48  48  33  57  0  57  66  18  69  113  84  115;
                    21  18  7  38  69  13  52  48  76  80  9  53  9  65  99  64  41  15  55  43  59  7  57  0  63  74  57  57  101  61;
                    50  75  57  84  64  75  103  19  58  24  67  15  54  70  79  19  25  59  19  26  33  56  66  63  0  59  7  61  74  52;
                    57  88  78  100  7  80  49  53  98  69  81  73  72  109  70  41  54  88  45  51  31  72  18  74  59  0  64  117  71  107;
                    46  68  51  77  69  68  102  17  57  27  61  9  48  67  82  23  23  52  21  24  37  50  69  57  7  64  0  57  77  48;
                    72  44  51  31  122  52  81  70  19  49  49  49  57  12  50  80  70  42  77  73  93  57  113  57  61  117  57  0  49  11;
                    121  83  100  63  73  90  69  92  33  51  93  77  106  39  4  81  100  90  89  100  88  105  84  101  74  71  77  49  0  48;
                    73  52  56  42  114  60  92  63  16  39  56  40  60  19  51  70  65  47  69  68  84  61  115  61  52  107  48  11  48  0];
        m(j,i)=m(i,j);% equal upper and lower triangular matrix
        end
    end
end
disp(m);
 i=1;
 x=1;
 temp=triu(m); %for coloring of the lines after computing path
 for i=1:n
     for j=1:n
         if(temp(i,j)~=0)
             lc(i,j)=x;      %just numbering in sequence for line count
             lc(j,i)=lc(i,j);
             x=x+1;      
         end
     end
 end
bg=biograph(triu(m),[],'showarrows','off','ShowWeights','on','EdgeTextColor',[0 0 1]);
view(bg);

over=0;
while(over==0)
from=input('Enter the source node no.: ');   %get inputs
to=input('Enter the destination node no.: ');
v=zeros(1,n);%visited matrix
d=randint(1,n,100);%distance to node matrix
p=zeros(1,n);%previous node matrix
s=from;
v(s)=1;%mark from as visited and initialixe d and p with 0
d(s)=0;
p(s)=0;
stop=0;

while(stop~=n)
stop=0;
for i=1:n
    if(v(i)~=1&&m(s,i)~=0)
        if(d(s)+m(s,i)<d(i))%if smaller than previous value replace
            d(i)=m(s,i)+d(s);
            p(i)=s;
        end
    else
        stop=stop+1;
    end
end
tempmat=d;
for i=1:n
    if(v(i)==1)
        tempmat(i)=100;%to find the next minimum
    end
end
[k z]=min(tempmat);
s=z;% next minimum node as source node
v(s)=1; % mark as visited
end
%%%%%%%%%%%%%%%%%%%%%%%%%computation over%%%%%%%%%%%%%%%%%
no=1:n;
fprintf('\nNodes:   ');
disp(no);
fprintf('Visited: ');
disp(v);
fprintf('Previous:');
disp(p);

i=1;
out=2;
dest(1)=to;
while(i==1)     %backtrace from destination to source
     to=p(to);
     dest(out)=to;
     out=out+1;
     if(to==from)
         i=0;
     end
end
bg=biograph(triu(m),[],'showarrows','off','ShowWeights','on','EdgeTextColor',[0 0 1]);
for i=1:out-1
set(bg.nodes(dest(i)), 'color', [1 0 0]);
set(bg.nodes(dest(1)),'color',[0 1 0]);
if(i<out-1)
set(bg.edges(lc(dest(i+1),dest(i))),'linecolor',[1 0 0]);
end
end
view(bg);
sample=input('Check Minimum distance for next instance y/n: ','s');
if(sample=='n')
    over=1;  
end
end

[dpb]

    m(1,j)=[0  39  ...

as you've surmised won't work; you're trying to put a whole array into a single array element.

Just assign

   m=[0  39 ...

first outside the loop and then do what you need with the array after.

What is the intent?

[Nsm]

oh i see.i understand now. it works but there's another error "Subscript indices must either be real positive integers or logicals." what is the meaning of that error? btw thank you @dpb :)

[Walter Roberson]

Somewhere you indexed with a fractional number, or with 0, or with a negative number, or with a complex number.

[Nsm]

yes it is,but i cannot find it. this code is to find the shortest distance between the nodes. btw thank you @Walter Roberson.

[Kaushik Lakshminarasimhan]

If you run this code as a script, it should display the exact line number that contains the error.

[Nsm]

yes it did. but still i couldn't solve the error. on my way to find the solution for that error.if anyone may know how to solve this error, please let me know. thank you. btw tq @Kaushik Lakshminarasimhan

[Walter Roberson]

We need your current code

[dpb]

And then the specific error in its entirety in context...

[Nsm]

ok this is my current code.

clc;
clear all;
disp('DIJKSTRA ALGORITHM');
n=input('Enter the no. of nodes: ');

for i=1:n
    %initialize
    for j=i:n       
        if(i==j)
    m(i,j)=0;
        else
            m=[0 39 22 59 54 33 57 32 89 73 29 46 16 83 120 45 24 32 36 25 38 16 43 21 50 57 46 72 121 73;
               39  0  20  20  81  8  49  64  63  84  10  61  25  49  81  81  58  16  72  60  78  24  69  18  75  88  68  44  83  52;
               22  20  0  39  74  18  60  44  71  73  11  46  6  61  99  61  37  10  51  40  59  5  62  7  57  78  51  51  100  56;
               59  20  39  0  93  27  51  81  48  80  30  69  45  32  61  97  75  31  89  78  97  44  83  38  84  100  77  31  63  42;
               54  81  74  93  0  73  43  56  104  76  76  77  69  111  72  46  56  84  49  53  33  69  12  69  64  7  69  122  73  114;
               33  8  18  27  73  0  45  61  71  88  8  63  22  57  87  77  54  18  68  56  71  20  61  13  75  80  68  52  90  60;
               57  49  60  51  43  45  0  85  88  115  52  103  60  75  64  85  79  63  83  78  70  58  38  52  103  49  102  81  69  92;
               32  64  44  81  56  61  85  0  74  43  55  23  40  81  97  17  8  50  8  7  23  41  53  48  19  53  17  70  92  63;
               89  63  71  48  104  71  88  74  0  38  69  51  75  16  35  75  77  61  77  80  90  76  116  76  58  98  57  19  33  16;
               73  84  73  80  76  88  115  43  38  0  81  28  72  53  55  38  49  70  42  50  53  75  83  80  24  69  27  49  51  39;
               29  10  11  30  76  8  52  55  69  81  0  55  16  57  91  71  48  11  62  50  68  14  64  9  67  81  61  49  93  56;
               46  61  46  69  77  63  103  23  51  28  55  0  44  59  81  32  26  46  29  29  45  47  76  53  15  73  9  49  77  40;
               16  25  6  45  69  22  60  40  75  72  16  44  0  67  105  56  33  16  46  35  53  2  57  9  54  72  48  57  106  60;
               83  49  61  32  111  57  75  81  16  53  57  59  67  0  39  88  82  51  87  85  103  67  113  65  70  109  67  12  39  19;
              120  81  99  61  72  87  64  97  35  55  91  81  105  39  0  84  104  90  93  104  90  104  82  99  79  70  82  50  4  51;
               45  81  61  97  46  77  85  17  75  38  71  32  56  88  84  0  23  67  9  21  15  57  48  64  19  41  23  80  81  70;
               24  58  37  75  56  54  79  8  77  49  48  26  33  82  104  23  0  44  14  3  25  34  51  41  25  54  23  70  100  65;
               32  16  10  31  84  18  63  50  61  70  11  46  16  51  90  57  44  0  58  47  67  16  72  15  59  88  52  42  90  47;
               36  72  51  89  49  68  83  8  77  42  62  29  46  87  93  9  14  58  0  12  16  48  48  55  19  45  21  77  89  69;
               25  60  40  78  53  56  78  7  80  50  50  29  35  85  104  21  3  47  12  0  22  36  48  43  26  51  24  73  100  68;
               38  78  59  97  33  71  70  23  90  53  68  45  53  103  90  15  25  67  16  22  0  54  33  59  33  31  37  93  88  84;
               16  24  5  44  69  20  58  41  76  75  14  47  2  67  104  57  34  16  48  36  54  0  57  7  56  72  50  57  105  61;
               43  69  62  83  12  61  38  53  116  83  64  76  57  113  82  48  51  72  48  48  33  57  0  57  66  18  69  113  84  115;
               21  18  7  38  69  13  52  48  76  80  9  53  9  65  99  64  41  15  55  43  59  7  57  0  63  74  57  57  101  61;
               50  75  57  84  64  75  103  19  58  24  67  15  54  70  79  19  25  59  19  26  33  56  66  63  0  59  7  61  74  52;
               57  88  78  100  7  80  49  53  98  69  81  73  72  109  70  41  54  88  45  51  31  72  18  74  59  0  64  117  71  107;
               46  68  51  77  69  68  102  17  57  27  61  9  48  67  82  23  23  52  21  24  37  50  69  57  7  64  0  57  77  48;
               72  44  51  31  122  52  81  70  19  49  49  49  57  12  50  80  70  42  77  73  93  57  113  57  61  117  57  0  49  11;
              121  83  100  63  73  90  69  92  33  51  93  77  106  39  4  81  100  90  89  100  88  105  84  101  74  71  77  49  0  48;
               73  52  56  42  114  60  92  63  16  39  56  40  60  19  51  70  65  47  69  68  84  61  115  61  52  107  48  11  48  0];
           m(j,i)=m(i,j);% equal upper and lower triangular matrix

          end
      end
  end
  disp(m);
   i=1;
   x=1;
   temp=triu(m); %for coloring of the lines after computing path
   for i=1:n
       for j=1:n
           if(temp(i,j)~=0)
               lc(1:i,1:j) = NaN;
               lc(i,j)=x;      %just numbering in sequence for line count
               lc(j,i)=lc(i,j);
               x=x+1;      
           end
       end
   end
  bg=biograph(triu(m),[],'showarrows','off','ShowWeights','on','EdgeTextColor',[0 0 1]);
  view(bg);

over=0;
while(over==0)
from=input('Enter the source node no.: ');   %get inputs
to=input('Enter the destination node no.: ');
v=zeros(1,n);%visited matrix
d=m;%distance to node matrix
p=zeros(1,n);%previous node matrix
s=from;
v(s)=1;%mark from as visited and initialixe d and p with 0
d(s)=0;
p(s)=0;
stop=0;

while(stop~=n)
stop=0;
for i=1:n
    if(v(i)~=1&&m(s,i)~=0)
        if(d(s)+m(s,i)<d(i))%if smaller than previous value replace
            d(i)=m(s,i)+d(s);
            p(i)=s;

          end
      else
          stop=stop+1;
      end
  end
  tempmat=d;
  for i=1:n
      if(v(i)==1)
          tempmat(i)=150;%to find the next minimum
      end
  end
  [k, z]=min(tempmat);
  s=z;% next minimum node as source node
  v(s)=1; % mark as visited
  end
  %%%%%%%%%%%%%%%%%%%%%%%%%computation over%%%%%%%%%%%%%%%%%
  no=1:n;
  fprintf('\nNodes:   ');
  disp(no);
  fprintf('Visited: ');
  disp(v);
  fprintf('Previous:');
  disp(p);

i=1;
out=2;
dest(1)=to;
dest(1:i,1:j) = NaN;
while(i==1)     %backtrace from destination to source
     to=p(to);
     dest(out)=to;
     out=out+1;
     if(to==from)
         i=0;
     end
end
bg=biograph(triu(m),[],'showarrows','off','ShowWeights','on','EdgeTextColor',[0 0 1]);
for i=1:out-1
set(bg.nodes(dest(i)), 'color', [1 0 0]);
set(bg.nodes(dest(1)),'color',[0 1 0]);
if(i<out-1)
set(bg.edges(lc(dest(i+1),dest(i))),'linecolor',[1 0 0]);
end
end
view(bg);
sample=input('Check Minimum distance for next instance y/n: ','s');
if(sample=='n')
    over=1;  
end
end

i tried to run the code and enter the source node 4 to destination node 9, then i get this error:

   Subscript indices must either be real positive integers or logicals. 
   Error in dijkstrasalgorithm (line 123)
  set(bg.nodes(dest(i)), 'color', [1 0 0]);

thank you @Walter Roberson and @dpb

[Walter Roberson]

Your initialization is just wrong.

You should have something like initializing m to that large matrix. Then take n = length(m) instead of using input() for it. Then your for loop should be

%initialize
for i=1:n
  for j=i:n       
    if i == j
      m(i,j)=0;
     else
        m(j,i) = m(i,j);
     end
   end
 end

However, your m is already initialized that way with one exception and so does not need any of that looping and test.

The exception is that m(16,18) = 67 but m(18,16) = 57 so likely there is a typo in entering the data.

Now look at your lines

i=1;
out=2;
dest(1)=to;
dest(1:i,1:j) = NaN;

you just set i to 1, but what is j? To know that you have to track back to your loop

for i=1:n
    for j=1:n
        if(temp(i,j)~=0)
            lc(1:i,1:j) = NaN;
            lc(i,j)=x;      %just numbering in sequence for line count
            lc(j,i)=lc(i,j);
            x=x+1;
        end
    end
end

and then know that when you have a for loop, that the loop control variable is left at the last value it was assigned during the loops, so j will be left assigned the value of n, so 30.

Thus, that dest(1:i,1:j) = NaN; is making the assignment dest(1,1:30) = NaN . That assignment overwrites the value set on the line before, dest(1)=to; which set the first entry to the destination node. Now the first entry is NaN. Things break down after that.

[Nsm]

oh yes there's 1 typo on the data. i corrected the data and put away dest(1:i,1:j) = NaN; since it will effects the first entry to the destination node.

clc;
clear all;
disp('DIJKSTRA ALGORITHM');
n=input('Enter the no. of nodes: ');
             m=[0  39  22  59  54  33  57  32  89  73  29  46  16  83  120  45  24  32  36  25  38  16  43  21  50  57  46  72  121  73;
               39  0  20  20  81  8  49  64  63  84  10  61  25  49  81  81  58  16  72  60  78  24  69  18  75  88  68  44  83  52;
               22  20  0  39  74  18  60  44  71  73  11  46  6  61  99  61  37  10  51  40  59  5  62  7  57  78  51  51  100  56;
               59  20  39  0  93  27  51  81  48  80  30  69  45  32  61  97  75  31  89  78  97  44  83  38  84  100  77  31  63  42;
               54  81  74  93  0  73  43  56  104  76  76  77  69  111  72  46  56  84  49  53  33  69  12  69  64  7  69  122  73  114;
               33  8  18  27  73  0  45  61  71  88  8  63  22  57  87  77  54  18  68  56  71  20  61  13  75  80  68  52  90  60;
               57  49  60  51  43  45  0  85  88  115  52  103  60  75  64  85  79  63  83  78  70  58  38  52  103  49  102  81  69  92;
               32  64  44  81  56  61  85  0  74  43  55  23  40  81  97  17  8  50  8  7  23  41  53  48  19  53  17  70  92  63;
               89  63  71  48  104  71  88  74  0  38  69  51  75  16  35  75  77  61  77  80  90  76  116  76  58  98  57  19  33  16;
               73  84  73  80  76  88  115  43  38  0  81  28  72  53  55  38  49  70  42  50  53  75  83  80  24  69  27  49  51  39;
               29  10  11  30  76  8  52  55  69  81  0  55  16  57  91  71  48  11  62  50  68  14  64  9  67  81  61  49  93  56;
               46  61  46  69  77  63  103  23  51  28  55  0  44  59  81  32  26  46  29  29  45  47  76  53  15  73  9  49  77  40;
               16  25  6  45  69  22  60  40  75  72  16  44  0  67  105  56  33  16  46  35  53  2  57  9  54  72  48  57  106  60;
               83  49  61  32  111  57  75  81  16  53  57  59  67  0  39  88  82  51  87  85  103  67  113  65  70  109  67  12  39  19;
              120  81  99  61  72  87  64  97  35  55  91  81  105  39  0  84  104  90  93  104  90  104  82  99  79  70  82  50  4  51;
               45  81  61  97  46  77  85  17  75  38  71  32  56  88  84  0  23  67  9  21  15  57  48  64  19  41  23  80  81  70;
               24  58  37  75  56  54  79  8  77  49  48  26  33  82  104  23  0  44  14  3  25  34  51  41  25  54  23  70  100  65;
               32  16  10  31  84  18  63  50  61  70  11  46  16  51  90  67  44  0  58  47  67  16  72  15  59  88  52  42  90  47;
               36  72  51  89  49  68  83  8  77  42  62  29  46  87  93  9  14  58  0  12  16  48  48  55  19  45  21  77  89  69;
               25  60  40  78  53  56  78  7  80  50  50  29  35  85  104  21  3  47  12  0  22  36  48  43  26  51  24  73  100  68;
               38  78  59  97  33  71  70  23  90  53  68  45  53  103  90  15  25  67  16  22  0  54  33  59  33  31  37  93  88  84;
               16  24  5  44  69  20  58  41  76  75  14  47  2  67  104  57  34  16  48  36  54  0  57  7  56  72  50  57  105  61;
               43  69  62  83  12  61  38  53  116  83  64  76  57  113  82  48  51  72  48  48  33  57  0  57  66  18  69  113  84  115;
               21  18  7  38  69  13  52  48  76  80  9  53  9  65  99  64  41  15  55  43  59  7  57  0  63  74  57  57  101  61;
               50  75  57  84  64  75  103  19  58  24  67  15  54  70  79  19  25  59  19  26  33  56  66  63  0  59  7  61  74  52;
               57  88  78  100  7  80  49  53  98  69  81  73  72  109  70  41  54  88  45  51  31  72  18  74  59  0  64  117  71  107;
               46  68  51  77  69  68  102  17  57  27  61  9  48  67  82  23  23  52  21  24  37  50  69  57  7  64  0  57  77  48;
               72  44  51  31  122  52  81  70  19  49  49  49  57  12  50  80  70  42  77  73  93  57  113  57  61  117  57  0  49  11;
              121  83  100  63  73  90  69  92  33  51  93  77  106  39  4  81  100  90  89  100  88  105  84  101  74  71  77  49  0  48;
               73  52  56  42  114  60  92  63  16  39  56  40  60  19  51  70  65  47  69  68  84  61  115  61  52  107  48  11  48  0];
disp(m);
 i=1;
 x=1;
 temp=triu(m); %for coloring of the lines after computing path
 for i=1:n
     for j=1:n
         if(temp(i,j)~=0)
             lc(1:i,1:j) = NaN;
             lc(i,j)=x;      %just numbering in sequence for line count
             lc(j,i)=lc(i,j);
             x=x+1;      
         end
     end
 end
bg=biograph(triu(m),[],'showarrows','off','ShowWeights','on','EdgeTextColor',[0 0 1]);
view(bg);

over=0;
while(over==0)
from=input('Enter the source node no.: ');   %get inputs
to=input('Enter the destination node no.: ');
v=zeros(1,n);%visited matrix
d=m;%distance to node matrix
p=zeros(1,n);%previous node matrix
s=from;
v(s)=1;%mark from as visited and initialixe d and p with 0
d(s)=0;
p(s)=0;
stop=0;

while(stop~=n)
stop=0;
for i=1:n
    if(v(i)~=1&&m(s,i)~=0)
        if(d(s)+m(s,i)<d(i))%if smaller than previous value replace
            d(i)=m(s,i)+d(s);
            p(i)=s;

          end
      else
          stop=stop+1;
      end
  end
  tempmat=d;
  for i=1:n
      if(v(i)==1)
          tempmat(i)=200;%to find the next minimum
      end
  end
  [k, z]=min(tempmat);
  s=z;% next minimum node as source node
  v(s)=1; % mark as visited
  end
  %%%%%%%%%%%%%%%%%%%%%%%%%computation over%%%%%%%%%%%%%%%%%
  no=1:n;
  fprintf('\nNodes:   ');
  disp(no);
  fprintf('Visited: ');
  disp(v);
  fprintf('Previous:');
  disp(p);

i=1;
out=2;
dest(1)=to;
while(i==1)     %backtrace from destination to source
     to=p(to);
     dest(out)=to;
     out=out+1;
     if(to==from)
         i=0;
     end
end
bg=biograph(triu(m),[],'showarrows','off','ShowWeights','on','EdgeTextColor',[0 0 1]);
for i=1:out-1
set(bg.nodes(dest(i)), 'color', [1 0 0]);
set(bg.nodes(dest(1)),'color',[0 1 0]);
if(i<out-1)
set(bg.edges(lc(dest(i+1),dest(i))),'linecolor',[1 0 1]);
end
end
view(bg);
sample=input('Check Minimum distance for next instance y/n: ','s');
if(sample=='n')
    over=1;  
end
end

but still there is the same error but on the other line.

 Subscript indices must either be real positive integers or logicals.
 Error in dijkstrasalgorithm (line 113)
  set(bg.edges(lc(dest(i+1),dest(i))),'linecolor',[1 0 1]);

still i dont get why that error always appears.sorry im asking too much. thank you @

[Nsm]

Thank you @Walter Roberson

[dpb]

"still i dont get why that error always appears"

I don't know what the code is intended to do but you've got the indexing expression

bg.edges(lc(dest(i+1),dest(i)))

where the array lc is set in the nested loop up at the top.

I took your code and ran it to the end of that loop and got the following info for it --

>> n  % check on n; looks ok...
n =
  30
>> whos lc  % ditto for lc size, shape
Name       Size            Bytes  Class     Attributes
lc        30x30             7200  double              

>> sum(isfinite(lc(:)))  % check we've got good values
ans =
  31
>>

And there's the problem; only 31 out of 900 values are actually even numbers, the rest are:

>> sum(isnan(lc(:)))  % look for NaN left...
ans =
 869
>>

Unless you pick only those i in the loop that have dest(i+1) one of those 31 positions for which lc isn't NaN, your code is going to error because you'll have the result after the array reference of

lc(NaN,dest(i))

which is going to error every time with exactly the error message you've got.

Set a breakpoint in the editor and run the code and see what the values of i, dest(i+1) and then revealingly what lc(dest(i+1)) are and I'll wager you'll see the cause of the error.

Precisely what you're trying to do and how to fix the logic I'll leave as "exercise for the student" not being familiar enough with the particular algorithm without further looking to see what it actually is.

[Nsm]

ok i will try and look for it. thank you @dpb :)