How to repeat value from start in buffer function Matlab

Hello Everyone, I hope you are doing well. I have the data shape 1x66656

I apply buffer function to get every 1000 samples,

Now the shape of the matrix is 1000x67. The remaining 344 value from 656 value are replaced by 0, Instead of 0 i want to repeat the matrix from the start to complete 1000 samples.

buffered = buffer(incomingdata, 1000); 

[Jan]

What exactly does "repeat the matrix from the start" mean? The first value? The first 344 elements?

Providing a small example would clarify this.

[Stephen john]

@Jan yes repeat the first 344 values, The buffer function place 0's to complete 1000 samples.

The should be generic using buffer function, for examples if i have 250 samples the buffer function place 750 zeros to complete 1000 samples. I want to to repeat value in place of 0's to complete 1000 samples

Answer 1

[Walter Roberson]

buffer() does not have any option for that.

The following code would be quite a bit shorter if we knew for sure that the incomingdata signal was already at least as large as the group size (1000)

%demo data
incomingdata = repmat((1:39).', 51, 1);

%the work
groupsize = 1000;

sig = incomingdata(:);
if isempty(sig)
    error('signal is empty, cannot buffer it');
end

sigsize = numel(sig);

fullcopies = floor(groupsize ./ sigsize);
sig = repmat(sig, 1+fullcopies, 1);
sigsize = numel(sig);
leftover = mod(sigsize, groupsize);
if leftover ~= 0
    sig = [sig; sig(1:groupsize-leftover)];
end

buffered = buffer(sig, groupsize);


%cross-check
buffered(end-30:end, end)

ans = 31×1

20 21 22 23 24 25 26 27 28 29