Invalid expression. When calling a function or indexing a variable

My base data is the following one (matrix):

I'm doing a Dijkstra's Algorithm - Matlab Formulation. But when I run the code, it appears this error:

I don't know why, I found this code on the internet but I don't know how to organice it. And it's worth mentioning that it has to read the data from a file.

%---------------------------------------------------
% Dijkstra Algorithm
% author : Dimas Aryo
% email : [e-mail]
%
% usage
% [cost rute] = dijkstra(Graph, source, destination)
% 
% example
% G = [0 3 9 0 0 0 0;
%      0 0 0 7 1 0 0;
%      0 2 0 7 0 0 0;
%      0 0 0 0 0 2 8;
%      0 0 4 5 0 9 0;
%      0 0 0 0 0 0 4;
%      0 0 0 0 0 0 0;
%      ];
% [e L] = dijkstra(G,1,7)
%---------------------------------------------------
datos = load('map.xlsx');
function [e L] = dijkstra(datos,1,12)
if s==d
    e=0;
    L=[s];
else
A = setupgraph(A,inf,1);
if d==1
    d=s;
end
A=exchangenode(A,1,s);
lengthA=size(A,1);
W=zeros(lengthA);
for i=2 : lengthA
    W(1,i)=i;
    W(2,i)=A(1,i);
end
for i=1 : lengthA
    D(i,1)=A(1,i);
    D(i,2)=i;
end
D2=D(2:length(D),:);
L=2;
while L<=(size(W,1)-1)
    L=L+1;
    D2=sortrows(D2,1);
    k=D2(1,2);
    W(L,1)=k;
    D2(1,:)=[];
    for i=1 : size(D2,1)
        if D(D2(i,2),1)>(D(k,1)+A(k,D2(i,2)))
            D(D2(i,2),1) = D(k,1)+A(k,D2(i,2));
            D2(i,1) = D(D2(i,2),1);
        end
    end
    
    for i=2 : length(A)
        W(L,i)=D(i,1);
    end
end
if d==s
    L=[1];
else
    L=[d];
end
e=W(size(W,1),d);
L = listdijkstra(L,W,s,d);
end
function G = exchangenode(G,a,b)
%Exchange element at column a with element at column b;
buffer=G(:,a);
G(:,a)=G(:,b);
G(:,b)=buffer;
%Exchange element at row a with element at row b;
buffer=G(a,:);
G(a,:)=G(b,:);
G(b,:)=buffer;
function L = listdijkstra(L,W,s,d)
index=size(W,1);
while index>0
    if W(2,d)==W(size(W,1),d)
        L=[L s];
        index=0;
    else
        index2=size(W,1);
        while index2>0
            if W(index2,d)<W(index2-1,d)
                L=[L W(index2,1)];
                L=listdijkstra(L,W,s,W(index2,1));
                index2=0;
            else
                index2=index2-1;
            end
            index=0;
        end
    end
end
function G = setupgraph(G,b,s)
if s==1
    for i=1 : size(G,1)
        for j=1 :size(G,1)
            if G(i,j)==0
                G(i,j)=b;
            end
        end
    end
end
if s==2
    for i=1 : size(G,1)
        for j=1 : size(G,1)
            if G(i,j)==b
                G(i,j)=0;
            end
        end
    end
end

[lol]

Do I have to do another script to call the functions? And how can I do it please? Or what will the other script has to contains?

[lol]

The example where I copied this code, is this one: https://la.mathworks.com/matlabcentral/fileexchange/36140-dijkstra-algorithm.

Can you please help me?

Answer 1

[Jan]

You cannot use constants in the definition of the inputs of a function:

function [e L] = dijkstra(datos,1,12)
%                               ^ ^^

Use the original code:

function [e L] = dijkstra(A,s,d)

Do not modify the function, but define the inputs you need in another script or function:

datos = load('map.xlsx');
[e, L] = dijkstra(datos, 1, 12);

[lol]

Okay, thanks! But I still have an error:

And I already did 2 scripts:

Untitled5.m is the one that I run

and the other script has the following code:

function [e L] = dijkstra(A,s,d)
if s==d
    e=0;
    L=[s];
else
A = setupgraph(A,inf,1);
if d==1
    d=s;
end
A=exchangenode(A,1,s);
lengthA=size(A,1);
W=zeros(lengthA);
for i=2 : lengthA
    W(1,i)=i;
    W(2,i)=A(1,i);
end
for i=1 : lengthA
    D(i,1)=A(1,i);
    D(i,2)=i;
end
D2=D(2:length(D),:);
L=2;
while L<=(size(W,1)-1)
    L=L+1;
    D2=sortrows(D2,1);
    k=D2(1,2);
    W(L,1)=k;
    D2(1,:)=[];
    for i=1 : size(D2,1)
        if D(D2(i,2),1)>(D(k,1)+A(k,D2(i,2)))
            D(D2(i,2),1) = D(k,1)+A(k,D2(i,2));
            D2(i,1) = D(D2(i,2),1);
        end
    end
    
    for i=2 : length(A)
        W(L,i)=D(i,1);
    end
end
if d==s
    L=[1];
else
    L=[d];
end
e=W(size(W,1),d);
L = listdijkstra(L,W,s,d);
end

function G = exchangenode(G,a,b)
%Exchange element at column a with element at column b;
buffer=G(:,a);
G(:,a)=G(:,b);
G(:,b)=buffer;
%Exchange element at row a with element at row b;
buffer=G(a,:);
G(a,:)=G(b,:);
G(b,:)=buffer;
function L = listdijkstra(L,W,s,d)
index=size(W,1);
while index>0
    if W(2,d)==W(size(W,1),d)
        L=[L s];
        index=0;
    else
        index2=size(W,1);
        while index2>0
            if W(index2,d)<W(index2-1,d)
                L=[L W(index2,1)];
                L=listdijkstra(L,W,s,W(index2,1));
                index2=0;
            else
                index2=index2-1;
            end
            index=0;
        end
    end
end

[lol]

what could be wrong? Can you help me please?

[Jan]

This thread seems to show, that you have solved the problem already: https://www.mathworks.com/matlabcentral/answers/1586044-unrecognized-function-or-variable-setupgraph