Using the matrix in different dimensions

Question

I have a matrix with the dimension 65536x2 which I want to use with another of dimension 256x256. How can I change the first matrix dimension to be 256x256? I tried reshape as follows:

 N=reshape(u,256,256);

But, got the following error:

Error using reshape
To RESHAPE the number of elements must not change.

What should I do in this case?

Thanks.

EDIT

The original question mentioned 1x65536, but realized that it should be 65536x2

use debugger: `>> dbstop if error` and verify that `numel(u)` indeed is 65536. — Shai, Jun 17 '13 at 13:29

score 2 · Answer 1 · answered Jun 17 '13 at 13:51

2

You could use N = reshape(u, 256, []) and then verify that size(N) is 256 x 256. This syntax for reshape automatically sizes the dimension specified by [] to whatever it needs to be to fit the number of elements in the array.

EDIT: My own attempt at reshaping a random 1 x 65536 matrix into a 256 x 256 matrix did not have a problem with either syntax, so I would suggest you verify that your initial matrix is in fact 1 x 65536 as well.

answered Jun 17 '13 at 13:51

Engineero

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Note that it will only work if `numel(u)` is a multiple of 256. – Stewie Griffin Jun 17 '13 at 13:57
@Engineero. You are right. I noticed that the matrix size is `65536 x2`. In this case, can I still `reshape` it? – Simplicity Jun 17 '13 at 14:04
Yes, you would just end up with a `256 x 512` matrix using the `reshape(u, 256, [])` command. – Engineero Jun 17 '13 at 14:05

score 0 · Answer 2 · answered Jun 17 '13 at 14:08

0

You cannot reshape 65536-by-2 array into 256-by-256 you have "extra" 65536 elements...

try

>> reshape( u, 256, 256 ,[] );

answered Jun 17 '13 at 14:08

Shai

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Using the matrix in different dimensions

2 Answers2