How to window sliding on matrix column?

Sorry for my weak English.

Dear all. I'am new in MATLAB, so I need your help.

I have some problem about how to write code for window sliding.

I have some matrix for example

1 2 3 4 5 6 7 8
9 1 2 3 4 5 6 7
8 9 1 2 3 4 5 6

So, I want to get group by window sliding like

(example. window size is 3 and overlap by 1 column)

group1    group2   group3   group4  ..... 

1 2 3     2 3 4    3 4 5     4 5 6  .....
9 1 2     1 2 3    2 3 4     3 4 5  .....
8 9 1     9 1 2    1 2 3     2 3 4  .....

Could you mind if I want you to show the code for solve this problem?

Best.

[Sean de Wolski]

What do you want to do with the window once you have it?

Answer 1

[Walter Roberson]

Use blkproc() if your MATLAB still has it.

Answer 2

[Andrei Bobrov]

eg:

EDIT

A= [1 2 3 4 5 6 7 8
9 1 2 3 4 5 6 7
8 9 1 2 3 4 5 6]

m = 3;
h = hankel(1:m,m:size(A,2))
B = arrayfun(@(i1)A(:,h(:,i1)),1:size(h,2),'un',0)
group = cat(3,B{:})

Bmatrix = cat(2,B{:})

ADD

A - your matrix(12x10)

m = 3; 
[a,b] = size(A); 
At = A.'; 
out = reshape(At(bsxfun(@plus,hankel(1:m,m:b),...
                   permute(0:b:b*(a-1),[1 3 2]))),(b-m+1)*m,[]).'

ADD2

m = 3;
n = size(A,2) - m +1;
out = zeros(size(A,1),m*n);
k = 2:-1:0;
for i1 = 1:n
    out(:,i1*m - k) = A(:,i1:i1+m-1);
end

ADD3

for example, your process is the summation

A= [1 2 3 4 5 6 7 8
9 1 2 3 4 5 6 7
8 9 1 2 3 4 5 6]
m = 3;
h = hankel(1:m,m:size(A,2))
B = arrayfun(@(i1)sum(A(:,h(:,i1)),2),1:size(h,2),'un',0)
Bmatrix = cat(2,B{:})

or

B = colfilt(A,[1 3],'sliding',@sum)
out = B(:,2:end-1)

[N K]

Could you mind to explain code in ADD and why use reshape?

Now, I have each column already (I have my process to transform matrix to 12x1).

But I don't know how to merge them together to create new matrix.

best.

[Andrei Bobrov]

Bmatrix = cat(2,B{:})

Answer 3

[N K]

Thanks for answer.

Than I have other problems now.

from

    m = 3;
    h = hankel(1:m,m:size(A,2))
    B = arrayfun(@(i1)A(:,h(:,i1)),1:size(h,2),'un',0)
    group = cat(3,B{:})

data will be in group. Than, I try to get data in each group to each variable

by create new variable in for loop like

[Bw,Bl]=size(B);
for loop = 1:1:Bl
         window(loop) = B{1,loop};            
end

But system doesn't let me do it. I want data in full matrix in each window.

How does to store each matrix in each variable ?

Best.

[Andrei Bobrov]

Division into separate variables-bad way, instead of individual variables window1,window2,... use B{1},B{2},...

[N K]

Thanks for recommend.

So, after process by using B{loop}, I will get matrix(1X12).

And I want take this matrix(1X12) connect each together to get new matrix(nX12).

Could you mind to show me how to do it?

Best.

[Andrei Bobrov]

B-cell array that contains 6 matrices of size 3 to 3, what is the matrix of size 1 to 12?

[N K]

Sorry for make confuse.

On example above, I give a example matrix data.

My real is matrix size n to 12 (n is depend on data).

I want to windowing by 3 and overlap by 1.

Than change matrix from windowing to size 1 to 12 and store them on new matrix.

So, could you show me how to connect 1to12 together to new make new matrix?

best.

[Andrei Bobrov]

i don't undestand. Please give example for martix with size of (eg) 5x12

[N K]

I really Sorry. I miss about row and column.

So, I will explain what I am doing to make you understand easily.

First, my matrix data is "12xN" (example 12X10)

1 2 3 4 5 6 7 8 9 10 -row 1

1 2 3 4 5 6 7 8 9 10 -row 2

....

1 2 3 4 5 6 7 8 9 10 -row 12

Second, I will use window sliding to grouping 3 column-overlap 1 column.

|1 2 3 |2 3 4 |4 5 6 |5 6 7| ... -row1

|1 2 3 |2 3 4 |4 5 6 |5 6 7| ... -row2

|.... |... |... |... |...

|1 2 3 |2 3 4 |4 5 6 |5 6 7| ... -row12

Third, process on each group to 12x1

|x1 |y1 |z1 | ...

|x2 |y2 |z2 | ...

|... |... |...| ...

|x12 |y12 |z12| ...

Finally, connect them together.

|x1 y1 z1 ... |

|x2 y2 z2 ... |

|.... |

|x12 y12 z12 ...|

[Andrei Bobrov]

A - your matrix(12x10)

m = 3;

[a,b] = size(A);

At = A.';

out = reshape(At(bsxfun(@plus,hankel(1:m,m:b),permute(0:b:b*(a-1),[1 3 2]))),(b-m+1)*m,[]).'

[Andrei Bobrov]

see ADD in my answer

[Andrei Bobrov]

and see comment by Sean de Wolski

[Andrei Bobrov]

what is going on in the process of: | 1 2 3 | -> | x1 |(example) ?

Answer 4

[Sukuchha]

use function nlfilter which is similar to blockproc which operates in a block but unlike blockproc its a sliding block window.

for mor info, doc nlfilter