I want to implement this matrix

0;Ip-l;0.............0

0;0;0;Ip-l;0.......0

.........................

0;0..............0;Ip-l

it is M-Nt x L matrix where M=128

      L=65

      p=64
1,3,5...columns are zero
2,4,6 columns have Ip-l in consecutive rows

[Andrei Bobrov]

M = 96;

N = 128;

A = zeros(M,N);

A(M+1:2*M+1:end) = Ip-1;

Answer 1

[Dr. Seis]

>> A = zeros(4,8);
>> A(:,2:2:end) = 5*eye(4,4);
>> A

A =

     0     5     0     0     0     0     0     0
     0     0     0     5     0     0     0     0
     0     0     0     0     0     5     0     0
     0     0     0     0     0     0     0     5

[Janet]

yes..this is I want..but I needed 96 x 128 matrix

[Dr. Seis]

Provided N is even:

M = 96;

N = 128;

A = zeros(M,N);

A(:,2:2:end) = (Ip-1)*eye(M,N/2)

[Janet]

Yes..I got it..thank you so much and without your help, I wouldn't have got a solution..thank you so much

Answer 2

[John D'Errico]

So many ways to do this. My favorite to recognize it as a block diagonal matrix.

d = repmat({[0 Ip-1]},1,64);
M = blkdiag(d{:});

If you want your matrix to be sparse (it surely should be, so why not use the capability?)

d = repmat({sparse([0 Ip-1])},1,64);
M = blkdiag(d{:});

I suppose this would work too. Making it sparse is trivial.

M = toeplitz([0, Ip-1,zeros(1,126)]);
M(2:end,:) = [];

[Janet]

using first command..how can i get 96 x 128 matrix

[Janet]

d = repmat({[0 Ip-1]},1,64);

M = blkdiag(d{:});

using this command...i want 96x128 matrix...i.e M-Nt x L matrix

M=128;Nt=2;L=16

Answer 3

[Sean de Wolski]

look at diag, and eye.

doc diag
doc eye

Please provide an actual matrix we can copy and paste into MATLAB (small example) if you would like more detail.

Answer 4

[G A]

A=[zeros(64,1),(Ip-l)*eye(64,64)]

[Janet]

0 48 0 0 0

0 0 48 0 0

0 0 0 48 0

0 0 0 0 48

i don't want such matrix

0 Ip-L 0.........................0

0 0 0 Ip-L 0................ 0

................................

................................

0 0 0.......................0 Ip-L

I want the above matrix

[Sean de Wolski]

Look at what G A's code is doing. I think you need to change the capitalization of one letter.

[Janet]

GA's code is like this:

0 48 0 0 0

0 0 48 0 0

0 0 0 48 0

0 0 0 0 48

but I want 1,3,5...columns to be zero

2,4,6,....columns to have Ip-l in consecutive rows

[Sean de Wolski]

A(1:2:end,:) = 0;

[Janet]

what is 1:2?

[Janet]

I need a M-Nt x L matrix i.e 96 x 128