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Please help create a transition matrix

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llrb
llrb on 20 May 2014
Commented: shahab anjum on 9 Mar 2020
Hi,
I hope anyone could help me, I'm kinda new to Matlab.
I have a variable 'velocity' with the value ranging from 0-48 km/hr. I have about 2250 of these data. I would like to create a frequency matrix of the speed transition follows another speed.
Velocity :
1.28
0.57
0.75
2.88
8.05
13.7
...
I would like to make a frequency matrix with this criteria:
Explanation: cell [2,2] --> velocity < 2 is followed by velocity < 2 one time.
I really appreciate any help you give. Thank you for your time.
Best,
Ella

Accepted Answer

Sven
Sven on 20 May 2014
Hi Ella,
The code below should do what you're looking for. I displayed the result as an image but you can just look at the final contents of freqMat
velocity = [1.28 0.57 0.75 2.88 8.05 13.7]
binEdges = 0:2:20; % 0 to 2 is the first bin, 2 to 4 is second bin, etc
[~,velBinNos] = histc(velocity,binEdges); % Histc just asks which bin each velocity belongs to
binTicks = binEdges(1:end-1); % Don't need the last bin edge
freqMat = zeros(length(binTicks));
fromBinNos = velBinNos(1:end-1);
nextBinNos = velBinNos(2:end);
for i = 1:length(fromBinNos)
freqMat(fromBinNos(i),nextBinNos(i)) = freqMat(fromBinNos(i),nextBinNos(i)) + 1;
end
figure, imagesc(binTicks,binTicks,freqMat)
xlabel 'Next velocity bin'
ylabel 'First velocity bin'
colorbar
Did this help you out?
Thanks, Sven.
  3 Comments
shahab anjum
shahab anjum on 9 Mar 2020
can you help me to please to build transition matrix if i have 1000x286 matrix.

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