Obtaning a matrix with the right indexes

My question:

A want to obtain a matrix A(4xN)=[A11 A21 A31 A41; A12 A22 A32 A42; ...; A1N A2N A3N A4N].

So I think that I have to do something like this:

syms A1 A2 A3 A4;

N=10; %for example

A=sym(zeros(4,N));

B=sym(zeros(4,N));

for i=1:N

A(:,i)=[A1; A2; A3; A4]

end

for j=1:N

B(:,j)=[j; j; j; j]

end

C=char(A)

D=char(B)

%And now I have to do a concatenation:

E=strcat([C,D])

%But this won't work of course and I don't know if some part of my program is correct or there is a different approach for this.

Thank you for your atention.

[Nuno]

O.K. I have almost what I want, but now matlab is giving me an error and I can't seem to go around it.

My program:

syms A1 A2 A3 A4;

N=20; %for example

A=sym(zeros(4,N));

B=sym(zeros(4,N));

H=sym(zeros(4,N));

A='A1A2A3A4'

B=1:1:N

C=mat2str(B)

%Concatenation

M=0;

s1=0:N-10

s2=1:N-9

for m=1:N

      if m<10

          H(1,m)=[A(1:2),C(2*m)];

          H(2,m)=[A(3:4),C(2*m)];

          H(3,m)=[A(5:6),C(2*m)];

          H(4,m)=[A(7:8),C(2*m)];

      end

      if m>=10

          for k=1:N

              H(1,m)=[A(1:2),C(2*m+s1(k):2*m+s2(k))];

              H(2,m)=[A(3:4),C(2*m+s1(k):2*m+s2(k))];

              H(3,m)=[A(5:6),C(2*m+s1(k):2*m+s2(k))];

              H(4,m)=[A(7:8),C(2*m+s1(k):2*m+s2(k))];

          end

      end

end

disp(H)

And the error:

Error using sym>convertExpression (line 2256)
Conversion to 'sym' returned the MuPAD error: Error: Unexpected 'integer'. [line 1, col 4]

Error in sym>convertChar (line 2167)
    s = convertExpression(x);

Error in sym>convertCharWithOption (line 2150)
        s = convertChar(x);

Error in sym>tomupad (line 1881)
        S = convertCharWithOption(x,a);

Error in sym (line 108)
            S.s = tomupad(x,'');

Error in sym/subsasgn (line 1614)
            if ~isa(B,'sym'),  B = sym(B); end

Error in la1 (line 27)
            H(1,m)=[A(1:2),C(2*m+s1(k):2*m+s2(k))];

[Nuno]

Can anyone help me with this?

Thank you.

Answer 1

[Walter Roberson]

Which MATLAB version are you using? If you are using R2011b or later, try just

A = sym('A', [4 N]);

[Nuno]

Thank you Walter Roberson! It makes a lot easier to read the program and it works fine too.

Answer 2

[Ahmed A. Selman]

Try this out to see if it solves the issue:

    clear 
    clc
    N=20; %for example
    H=sym(zeros(N,4));
    B=1:N;
    %Concatenation
    for j=1:4
        for m=1:N
            H(m,j)=['A',num2str(j),num2str(m)];
        end
    end
    disp(H)

[Nuno]

Thank you Ahmed A. Selman! To get what I want I just had to make H(j,m) instead of H(m,j).