## How to use reshape in specific case

### Jan (view profile)

on 13 May 2013
Accepted Answer by James Tursa

### James Tursa (view profile)

Hi all, can anyone help me with reshaping 3D matrix to 2D in way shown below? Lets say I have a 3D matrix A (A = round(rand(3,3,3)*10))

A(:,:,1) =

```     0     8     7
1     9     4
1     3     5```

A(:,:,2) =

```     7     5     5
10     7     7
8     4     0```

A(:,:,3) =

```     2     7     4
5     8     8
2     4     6```

And i want a 2D matrix C C =

```    0     8     7
1     9     4
1     3     5
7     5     5
10     7     7
8     4     0
2     7     4
5     8     8
2     4     6```

Thank you for any input for this problem

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### James Tursa (view profile)

Answer by James Tursa

### James Tursa (view profile)

on 13 May 2013
Edited by James Tursa

### James Tursa (view profile)

on 13 May 2013

For your specific example,

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

Alter the last two dimensions to fit your actual problem. The purpose of the permute in the above expression is to get the 3rd dimension next to the 1st dimension in memory, and then a simple reshape will finish the job.

Jan

### Jan (view profile)

on 14 May 2013

Thank you for your reply. Another liked question. How to do this in reverse? lets say I have a previosly created 2D matrix and I want to create 3D matrix. I am still not quite sure how to use permute.

Jan

### Jan (view profile)

on 14 May 2013

Never mind spend another 14 minutes to think of it twice. I appreciate yor help.

This worked

C = reshape(permute(B,[2 1]),3,3,3); NewC = permute(C, [2,1,3])

Andrei Bobrov

### Andrei Bobrov (view profile)

on 14 May 2013
```C = reshape(permute(A,[2 1 3]),3,[])'
```
```A = permute(reshape(C,3,3,[]),[1 3 2])
```

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