How to separate Vector in different Lenghts

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David Bloch 2015-11-27

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回答： dpb 2015-11-27

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Hello,

i have one Vector CamData(1:128)

and I want to separate it to two different Vectors:

CamDataNEW1 = CamData(10:Value)
CamDataNEW2 = CamData(Value+1:118)

I program for an µC so, but i don't want to allow variable Sized Signals (processing Speed).

So i am searching for a Solution with preallocated Variables.

camDataNew1 = cell(1:128);
camDataNew2 = cell(1:128);
camDataNew1 = arr_CameraDiff(10:n_TrackMiddle);
camDataNew2 = arr_CameraDiff(n_TrackMiddle+1:118);

After this I want to look for Minima in each Part and get the Index.

How can I accomplish this?

Thank you for helping out!

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Walter Roberson 2015-11-27

cell(1:128) would try to create a cell array with 128 dimensions, a 1 x 2 x 3 x 4 x 5 x 6 x ... x 128 cell array.

cell arrays are dynamic structures that are effectively variable sized signals, which you do not wish to use.

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Answer 1

dpb 2015-11-27

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Well, unless you fix the value of Value it's going to be a variable-length vector by definition. I don't know where the uC is coming in at; if you have the toolbox you can generate code for such but I'd certainly not use cell arrays for the purpose.

If you have a input buffer of length 128 then just write in Matlab

v1=CamData(1:Value);
v2=CamData(Value+1:end);

If you wish if there's a max for Value less than length(CamData) then you can write

v1=zeros(1:Value);
v2=zeros(1:maxLength);

to preallocate the two arrays. Then you'd write

v1(1:Value)=CamData(1:Value);
v2(1:maxLength-Value)=CamData(Value+1:end);

to assign altho note here you'll have to clear the buffer each time of any extraneous values left over from a previous iteration if Value changes. If, of course, it is fixed then you can make the two buffers identically the correct size. You also, if do the above must treat the "empty" values correctly for whatever is the proper behavior. All in all, it may well be less actual overhead to allocate the proper size instead.

The min/location is trivial with the alternate optional return values.