Index in position 1 exceeds array bounds (must not exceed 1)

Hello, I'm trying to run this code (gauss elimination), but i get an error message :Index in position 1 exceeds array bounds (must not exceed 1). the error message comes from "am(in,in)=bm(in,im);". What does "Index in position 1 exceeds array bounds (must not exceed 1)" mean? and how to solve this?

Here is code :

n=3
a=[1,2,3;4,3,2;,9,8,7]
b=[3;4;2]
k=n;
for i=1:k
    for j=1:k+1
        if j~=k+1
            am(i,j)=a(i,j);
        else
            am(i,j)=b(i);
        end
    end
end

m=n+1;
for i=1:n
    for j=1:m
        bm(i,j)=am(i,j)/am(i,i);
    end
    for k=1:n
        for l=1:m
            if i==k
                bm(k,l)=am(k,l)-bm(i,l)*am(k,i);
            end
        end
    end
    for in=1:n
        for im=1:m
            am(in,im)=bm(in,im);
        end
    end
end
for i=1:n
    c(i)=am(i,m);
end

[Torsten]

The array "bm" has size (1,4) when you enter the nested for loop

  for in=1:n
     for im=1:m
       am(in,im)=bm(in,im);
      end
  end
  

Thus for in>1, you try to access elements in "bm" that do not yet exist.

Since I did not try to understand your code, you have to solve this problem on your own.

[noe]

thank you sir

Answer 1

[Jan]

The message:

"Index in position 1 exceeds array bounds (must not exceed 1)"

seems to be very clear: The first index of an array is 2, but the array has a length of 1 in the first dimension only. Use the debugger to examine such problems:

dbstop if error

Type this in the command window and run the code again. When Matlab stops at the error, cehck the sizes of the used variables:

size(bm)
in
im

By the way, this can be simplified:

for i=1:k
    for j=1:k+1
        if j~=k+1
            am(i,j)=a(i,j);
        else
            am(i,j)=b(i);
        end
    end
end

to:

am = [a(1:k, 1:k), b];

% Or:
am = [a, b];

Answer 2

[Gul Rukh Khan]

Respected Sir,

I have one question in my 10x10 matrix image.

I want to compare first pixel of 10x10 matrix with the right side and bottom side element, and based on the difference whichever is greater move towards that direction.

This is bacially for Edge Detection, sir.

Can you help me accordingly. i am waiting for your prompt response. Thanks

best Regards

gul Rukh Khan

[Jan]

Please do not attach a new question to an existing thread. Open a new thread instead and remove this message. Thanks.

[Marcel]

1. Chill bro

Answer 3

[NOR AZIERA]

Sir...can i ask u ..how to solve this problem?

n=3; A=randn(n); A=A'*A; [V,D]=eig(A);

for i=1:n

    X=outprod(V(:,i),D(i))*V'
    display(X);
    display(A');

end

[Jan]

@NOR AZIERA: Please do not post a new question in the section of answers of another question.

You have asked this in another question already, so please delete this answer.

[Rahul Pandit]

Hi Sir

I need your help develop a code for cross correlation using the delay.

I have two 5Sec signals and i want to do the cross corelation of both the signals.

a = xlsread(signals 5sec.xls);
t1 = a(:,1);  %time (Time is same for both the signal)
yR1 = a(:,2);  % 1st signal
yR2 = a(:,4);   % 2nd signal
% Cross Correlation
[r,lags] = xcorr(yR1,yR2);
plot(lags,r,'color','r','linewidth',1.6);

But i want to do the delay of 1 sec and then do the cross correlation using the for loop, i must to iterate the signals 1sec to 5sec for 1st signal and same thing i have to repeate in negative direction also. so i can get the neagtive and positive both the pulses.

Please help me to grow my self.

Answer 4

[fatma]

code:

    Ncyc = Ncyc_primes (find (gcd (Ncyc_primes, N) ==1),  1,   'last ')

erorr:

Index in position 1 exceeds array bounds. Index must not exceed 1.

[Jan]

This line cuases the same error message, but has no other connection to the original error message. Most of all, it is not an answer, but a new question, I assume. So please open a new question and delete the message here. Thanks.

Answer 5

[Somad]

could someone help me please,

this is my loop:

for tdz = 1:length(t_vec)-1 %%%integrator integrates to tdx+1
    for idz = 2:length(z_vec)-1 % because 1 is T_mat(1,:), bc, doesnot change, also length(x_vec) = T_mat(end,:)
        CCO2v(idz, tdz+1) = ( CCO2v(idz,tdz)+ (-CCO2v(idz,tdz+1) * (uG(idz+1,tdz) - uG(idz-1,tdz))/dz - uG * (CCO2v(idz+1,tdz) - CCO2v(idz-1,tdz))/dz - aw*NCO2)*dt)/gasholdup;
        CCO2l(idz, tdz+1) = (CCO2l(idz,tdz) - (uL*(CCO2l(idz-1,tdz) - CCO2l(idz+1,tdz))/dz + aw*NCO2)*dt)/liqholdup; 
        TGmat(idz, tdz+1) = ((-uG*(TGmat(idz+1,tdz) - TGmat(idz-1,tdz))/dz + (aw/(CCO2v(idz, tdz+1)*cp_CO2))*hg*(TLmat(idz, tdz+1)-TGmat(idz, tdz+1)))*dt + TGmat(idz,tdz))/gasholdup;
        TLmat(idz, tdz+1) = ((-uL*(TLmat(idz-1,tdz) - TLmat(idz+1,tdz))/dz - aw*hg(TLmat(idz, tdz+1)-TGmat(idz, tdz+1))/(CCO2v(idz, tdz+1)*cp_CO2) - dH*NH2O - dHH2O*NH2O)*dt + TLmat(idz,tdz))/liqholdup;
    end
    
end

the error also: Index in position 1 exceeds array bounds. Index must not exceed 1.

Error in Absorber (line 235)

CCO2v(idz, tdz+1) = ( CCO2v(idz,tdz)+ (-CCO2v(idz,tdz+1) * (uG(idz+1,tdz) - uG(idz-1,tdz))/dz - uG * (CCO2v(idz+1,tdz) - CCO2v(idz-1,tdz))/dz - aw*NCO2)*dt)/gasholdup;

[Torsten]

How did you initialize the 2d-array CCO2v ?

On the right-hand side of the equation

CCO2v(idz, tdz+1) = ( CCO2v(idz,tdz)+ (-CCO2v(idz,tdz+1) * (uG(idz+1,tdz) - uG(idz-1,tdz))/dz - uG * (CCO2v(idz+1,tdz) - CCO2v(idz-1,tdz))/dz - aw*NCO2)*dt)/gasholdup;

you try to access elements of CCO2v that do not yet seem to exist.

Further, the right-hand side contains CCO2v(idz,tdz+1) which you want to define by the equation. This must be wrong.