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From: Andy on 8 Jul 2010 14:38
My incorrect code is as follows, can you tell me where I am going wrong?

C=[];
for x=1:64
for y=1:64
for z=1:64
coords=cat(2,x,y,z);
C(x,y,z)=cat(3, C, coords);
end
end
end
From: Jan Simon on 8 Jul 2010 14:50
Dear Andy,

> One last thing, how do I create a [64^3x3] matrix?
C = zeros(64, 64, 64);

> I was trying to create a [64x64x64] matrix which just consisted of strings representing the coordinates but that did not work?

Strings?! Strings are vectors of characters like 'hello' -- not suitable for representing coordinates.

Jan
From: Andy on 8 Jul 2010 15:04
> Strings?! Strings are vectors of characters like 'hello' -- not suitable for representing coordinates.

How then do I allow the elements of my matrix to each have an x, y, and z value? With zeros I can create the array, but can't correctly add in the proper coordinates to replace the 0 in each position.
From: Jan Simon on 8 Jul 2010 15:17
Dear Andy,

> C = zeros(64, 64, 64, 3); % !!! ever preallocate !!!
> for x=1:64
> for y=1:64
> for z=1:64
> C(x, y, z, 1:3) = [x, y, z];
> end
> end
> end

This could be reshaped finally:
C = reshape(C, 64^3, 3);

Inspect the values of C (a smaller size would be helpful). Then you will see, that there are much more efficient and nicer method to create C.

Kind regards, Jan
From: Andy on 8 Jul 2010 16:30
Jan,
Thank you so much that works great!
However when I attempt to multiply it by the rotation matrix it won't let me because the dimensions don't agree.
I tried making individual x, y, and z matricies of C such that Cx=squeeze(C(:,1,1,:))
These I can multiply by my 2D rotation matrix but it appears I am missing some values because I end up with a 64x3 array for each, which gives a total of 576 values, substaintially less than the 786432 I would expect in a 64x64x64x3 matrix like I started with.

I'm sorry that I have so many questions, I'm still not very adept with the multidimensional array manipulations.

Thanks again!
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