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How can i reshape a 20370x1 matrix into 2037x10x1?

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I have tried to execute this using reshape and permute command.The problem is i am getting either the dimensions as 2037x1x10 or 2037x10. I want the dimension to be 2037x10x1. This is the solution i come up with so far,
>> r=permute(reshape(modu_data_QAM',2037,10),[2;3;1]);
The result= 10 1 2037
modu_data_QAM is a matrix of 20370x1 dimension.

Accepted Answer

John D'Errico
John D'Errico on 15 Jul 2015
Edited: John D'Errico on 15 Jul 2015
MATLAB treats ALL matrices as having essentially an infinite number of trailing singleton dimensions. So a 2x3 matrix is really 2x3x1x1x1x1x1x1... Those trailing singleton dimensions are not reported by size or whos however.
X = zeros(2,3,1,1);
whos X
Name Size Bytes Class Attributes
X 2x3 48 double
ans =
2 3
However, MATLAB indeed knows that X has trailing singleton dimensions. You can convince yourself of that easily enough.
ans =
ans =
Your 2037x10 matrix is indeed a 2037x10x1 matrix. So a simple reshape was all you needed to do.
B = reshape(A,[2037,10]);
  1 Comment
shubhi bhadauria
shubhi bhadauria on 15 Jul 2015
Thanks for the reply. Actually i was trying to use the step command for getting a modulated OFDM signal.Thus this error was coming up,that the input should be 2037x10x1. I'll look into my code again> Thanks once again:)

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More Answers (1)

dpb on 15 Jul 2015
All arrays in Matlab have implied but not explicit unity dimensions in higher dimensions; you can refer to the array with the third subscript explicitly if need to.
Smaller example of same thing...
>> x=rand(200,1);
>> size(x)
ans =
200 1
>> y=reshape(x,20,10,1);
>> size(y)
ans =
20 10
>> y(20,10)==y(20,10,1)
ans =
As you can see, referring to the resulting y array with either two or an explicit third (unity) index results in the same thing.
Why do you think you need the explicit third dimension; show us some code snippets of what you're after that can't seem to accomplish (other than just wishing the implicit dimension would show up with size, say).


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