Reshaping a 2 d matrix into a 3 d matrix row wise.

Hello, and thanks for taking the time to read this:

I have a 100 x 99 matrix of ratings. I would like to reshape the matrix into a 9x11x100 array where the first row represents the first 9 horizsontal items of the first row. Byu way of a smaller example, imagine the data were:

7 6 5 4 5 6

1 5 6 6 6 2

1 6 6 6 6 1

5 5 6 6 7 2

I would like the result to be:

765

456

156

662

556

672

Can anyone please help with this?

Answer 1

[the cyclist]

For your small example, if A is your original matrix, then

permute(reshape(A',3,2,[]),[2 1 3])

For the larger one,

permute(reshape(A',9,11,[]),[2 1 3])

[Russ]

Great advice. The following alternative (which I would never have reached without your input) seemed to do the trick. I might haver described the problem incorrectly.

permute(reshape(A', 11,9,[]), [2 1 3])

Thanks!

Russ

[the cyclist]

Yes, I see you effectively have these two conflicting statements in your question:

• result is 9x11x100
• first row is the first 9 items

These are conflicting because if the result is 9x11x100, then the first row has 11 items.

But it sounds like you got what you needed.

[Russ]

Yep, now I understand where I went wrong. The first row was supposed to be the first 11 items, not the first 9 items. Thanks so much for solving this problem!

Answer 2

[Daniel Vieira]

A=randi(10,100,99); % example of what your matrix might be
B=permute(reshape(A',9,11,[]),[2 1 3]) % solution

[Russ]

Thanks! The following alternative seemed to do the trick.

permute(reshape(A', 11,9,[]), [2 1 3])

Thanks!

Russ