Hi Community, I got a problem with my gauss elimination and I'm unable to fix it myself.

Hi Community, I got an error in the following code. May you guys help me with this code, as its important for me to get it run until tomorrow and it seems like I'm unable to fix it myself.

I get a 'NaN' error for

A = [0, 1, 2, 5, 1, -3; 1, 0, 3, -1, 1, -2; 2, -1, 4, 3, 1, 0; -1, 3, 3, 4, 2, -2]
b = [4; -7; -7; 10]

and it says 'Index in position 1 exceeds array bounds (must not exceed 3)' for

A = [0, 0, -2, 0, 7; 1, 2, -5, 3, 6; 2, 4, -5, 6, -5}
b = [12; 14; -1]  

The code is as follows

function [ C ] = gaussalgorithmus( A, b )

count_ze = 1;
count_sp = 1;

eins_ze = -1;
null_ze = -1;
merker  = -1;
[z, s]  = size (A);  
S
C = [A, b];
for k1 = 1 : s                            
    for k2 = 1 : z                       
        
        if C(k1, k2) == 1 && k1 >= count_ze
            eins_ze = k1;
        end
    end
    if eins_ze ~= -1         
        
        C([count_ze, eins_ze], :) = C([eins_ze, count_ze], :);
        
    elseif (eins_ze == -1) && (rund(C(count_ze,count_sp)) ~= 0)
        
        lambda =  1/rund(C(count_ze,count_sp));
        
        C(count_ze, :) = C(count_ze, :) * lambda;
        
    elseif (eins_ze == -1) && (rund(C(count_ze,count_sp)) == 0)
        
        for k3 = count_ze : z
            if rund( C(k3, count_sp)) ~= 0
                null_ze = k3;
            end
        end
        
        if null_ze ~= -1
            
            C([count_ze, null_ze], :) = C([null_ze, count_ze], :);
            
            C(count_ze, :) = C(count_ze, :) * 1/rund(C(count_ze, count_sp));
            
        else
            merker = 1;
        end
    end
    
    for k4 = 1 : z
        if k4 ~= count_ze && rund(C(k4,k1)) ~= 0 && merker ~= 1 && ...
                rund(C(count_ze, count_sp)) ~= 0 
            C = vielfachesaddieren(C, k4, count_ze, -1*(rund(C(k4,k1)) / ...
                rund(C(count_ze,count_sp))));
        end 
    end
    
    if merker ~= 1
        
        C(count_ze, :) = C(count_ze, :) * (1 / rund( C(count_ze, count_sp)));
    end
    
    count_ze = count_ze + 1;
    count_sp = count_sp + 1;
    eins_ze  = -1;
    if null_ze ~= -1
        count_ze = count_ze - 1;
    end
    if merker == 1
        count_ze = count_ze - 1;
        merker = -1;
    end
    
    for k5 = 1 : z  
        for k6 = 1 : s + 1
            if abs( C(k5, k6)) < 10e-10
                C(k5, k6) = 0;
            end
        end
    end 
    if count_ze == z + 1
        break
    end
end
end



function [ numb ] = rund( number )                                 
if abs(number) < 10e-13
    numb = 0;
else 
    numb = number;
end
end



function [ A ] = vielfachesaddieren(A, j ,i, faktor)               
A(i,:) = A(i,:) * faktor;        
A(j,:) = A(j,:) + A(i,:);
end

[Paul]

Suggest you carefully go through the code and recheck all of the indexing operations. For example, in this line

[z, s]  = size (A);

z is the number of rows of A and s is the number of columns. Then later on k1 loops from 1 to s (the number of columns), and k2 loops from 1 to z (the number of rows). But then in this line

if C(k1, k2) == 1 && k1 >= count_ze 

k1 is the row index and k2 is the column index, which is backwards. I think there may be other errors like this as well.