Index in position 2 exceeds array bounds (must not exceed 1).

I kept getting this error message when I try to create a for loop to generate a 1x25 array:

"Index in position 2 exceeds array bounds (must not exceed 1)"

The array should be

A = [1 2 3....25]

Any help would be greatly appreciated. This is what I have so far,

A = [1]
for i = 2:25
   A(:,i) = A(:,i+1)
end

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Star Strider]

You have assigned ‘A’ as a scalar. Preallocating is a good idea, however this would likely be more effective:

A = ones(1,24);
for i = 1:25
   A(:,i+1) = A(:,i)+1;
end

[E]

I'm not exactly sure where to input that. How does that fit into my code? With the for loop.

[Star Strider]

My code is the entire loop. It begins with the preallocation (important for efficiency), then uses the loop to add 1 to each succeeding element in the vector.

Note that the code you posted does not actually do any addition. It simply repeats the initial value in each succeeding element of ‘A’.

[E]

It worked! thank you so much for your help!

[Star Strider]

As always, my pleasure!

Answer 2

[madhan ravi]

A=zeros(1,25); %preallocation is important
A(1)=1;
for k=2:25
    A(:,i)=A(:,i-1)+1;
end
A

Note: This task doesn’t require loop , just vectorization should do the job.

A=1:25;

Bit it’s pretty clear that you want to get in practice with a for loop.

[E]

Thank you

[Aarpita Sood]

I am using KNN classifier

k_nn=ind(:,1:k);

nn_index=k_nn(:,1);

These lines show error "Index in position 2 exceeds array bounds (must not exceed 22)"

Any clarifications would be appreciated.

Answer 3

[nag raj]

function [Qr, lolb] = solveP3(Qr,Xr)

global K M H alpha beta0 delta_t Dmax B sigma_2 Lamda Pk q0 qF Sk F_1 w u tolerance

Ql = Qr;

l = 0; tol = tolerance;

Lo = [];

for l = 1: 1000

Qlt = repelem(Ql,1,1,K);

J = H^2 + sum( (Qlt - w).^2 ,1);

J = reshape(J, [M,K] );

I = F_1*Pk*dB2dec(beta0)*(alpha/2)*log2(exp(1)) ./ (J .* (dB2dec(sigma_2) * dB2dec(Lamda) * J .^(alpha/2) + F_1*Pk*dB2dec(beta0)));

A = log2(1 + (F_1*Pk*dB2dec(beta0)) ./ (dB2dec(sigma_2) * dB2dec(Lamda) * J .^(alpha/2)) );

cvx_begin quiet

variables Q(2,M)

variables lo(1)

expression LO(K)

maximize (sum(lo))

subject to:

for k = 1 : K

LO(k) = 0;

for m = 1 : M

Rlb = A(m,k) - I(m,k) * (sum_square_abs( Q(:,m) - u(:,k))) + I(m,k) * (sum_square_abs( Ql(:,m) - u(:,k)));

LO(k) = LO(k) + Xr(m,k) * Rlb;

end

(1/(Sk/(B*delta_t))) * LO(k) >= lo; %Constraint (17)

end

for m = 2: M

norm(Q(:,m) - Q(:,m-1)) <= Dmax;

end

Q(1,1) == q0(1);

Q(2,1) == q0(2);

Q(1,M) == qF(1);

Q(2,M) == qF(2);

cvx_end

Lo = [Lo;sum(lo)];

Ql = Q;

if (l >= 2) &&(Lo(l) - Lo(l-1) < tol)

break;

end

end

Qr = Q;

lolb = Lo(l);

end

function [dB] = dec2dB(dec)

dB = 10*log10(dec);

end

function [dec] = dB2dec(dB)

dec = 10.^(dB/10);

end

same problem

Index in position 2 exceeds array bounds (must not exceed 1).

Error in solveP3 (line 41)

Rlb = A(m,k) - I(m,k) * (sum_square_abs( Q(:,m) - u(:,k))) + I(m,k) * (sum_square_abs( Ql(:,m) - u(:,k)));

[Star Strider]

Post this as a new question. It is not an Answer to this thread.

Answer 4

[Samy Alkhayat]

Hello,

I have the same error when I run this piece of code to come up with a property of a mixture of 2 components

rDCN=randsample(DCN,Ncomponents);
v = rand(1,7)';
rv = randsample(v,Ncomponents);
for i = 1:Ncomponents
    D = rDCN(:,i).*rv(:,i);
end

please advise