split up a matrix at discontinuities
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I have matricies of varying sizes, how can i split them where the time is discontinous? Time is in seconds with 60 seconds in between each interval, otherwise it is considered "discontinous"
Example:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1676226/image.png)
Here the data set is "discontinous" between 720 and 53138, how can I split them along with their paired Y axis without having to look at where the discontinuity is and manaually creating the different matricies?
1 个评论
AH
2024-4-22
The criterion for splitting the data is discontinuity. So I don't think that it's possible to split the data into pieces without specifying locations where discontinuity occurs.
Here is one simple code
t = [0:60:720 53138:60:53618 101413:60:101713]';
y = 2*t;
% Find discontinuity
dt = diff(t);
disIdx = find(abs(dt) > 60);
N = length(t);
disIdx = [disIdx(:);N]; % add last segment
Ndis = length(disIdx);
% Split data
Y = cell(Ndis,1);
beginIdx = 1;
for i = 1:Ndis
idx = beginIdx:min(N,disIdx(i));
Y{i} = [t(idx),y(idx)];
beginIdx = disIdx(i)+1;
end
Y
采纳的回答
Voss
2024-4-22
A = [0 34.4; 60 33.3; 120 32.2; 180 31.1; 240 30; 300 28.9; 360 27.9; 420 26.8; 480 25.7; 540 24.7; 600 23.6; 660 22.6; 720 21.6; 53138 68.7; 53198 69.9; 53258 71.1; 53318 72.2; 53378 73.4; 53438 74.5; 53498 75.5; 53558 76.5; 53618 77.4];
disp(A)
idx = find(diff(A(:,1)) ~= 60);
s_idx = [1; idx+1];
e_idx = [idx; size(A,1)];
result = arrayfun(@(s,e)A(s:e,:),s_idx,e_idx,'UniformOutput',false)
celldisp(result)
更多回答(1 个)
Lokesh
2024-4-22
Hi puccapearl,
I understand that you are looking to split the matrix into smaller matrices(or segments) whenever there is a discontinuity in time greater than 60 seconds between successive entries.
Here are the steps you can follow to identify discontinuities and segment them accordingly:
- Calculate Time Differences: Compute the difference between successive time points to identify where the discontinuities (gaps greater than 60 seconds) occur.
- Identify Discontinuities: Use the calculated differences to find indices in the matrix where these discontinuities happen.
- Split the Matrix: Based on the identified indices, split the matrix into segments, each representing a continuous time series without discontinuities greater than 60 seconds.
Below is a sample MATLAB code snippet that demonstrates how to split the matrix based on discontinuity:
% Define the matrix
data = [
0, 1.4;
60, 1.2;
120, 1.3;
180, 1.3;
720, 1.3;
780, 1.5;
840, 1.23
];
% Calculate the differences between successive time points
timeDiffs = diff(data(:,1));
% Identify where the time difference is greater than 60 seconds
discontinuities = find(timeDiffs > 60);
% Initialize a cell array to hold the continuous segments
segments = {};
% The starting index for the first segment
startIndex = 1;
% Iterate through each discontinuity to split the matrix
for i = 1:length(discontinuities)
% The discontinuity index marks the end of the current segment
endIndex = discontinuities(i);
% Extract the segment and add it to the segments array
segments{end+1} = data(startIndex:endIndex, :);
% Update the start index for the next segment
startIndex = endIndex + 1;
end
% Add the last segment from the last discontinuity to the end of the data
segments{end+1} = data(startIndex:end, :);
% Each cell of 'segments' now contains a continuous part of the original matrix
Refer to the following MATLAB documentation to know more about 'diff' and 'find':
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