how to use logic array
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i have a 8x6 logical array
result1 =
8×6 logical array
1 0 0 0 0 0
0 0 0 1 0 0
0 0 0 0 1 0
0 0 0 0 0 0
0 1 0 0 0 0
0 0 1 0 0 0
0 0 0 0 0 1
0 0 0 0 0 0
how to use this logical array to extract the values in two matrix assosiated with logical ones
8 个评论
madhan ravi
2019-8-1
You need to be clear how does your look like? the sizes??
karishma koshy
2019-8-1
KSSV
2019-8-1
What exactly is your problem?
karishma koshy
2019-8-1
编辑：karishma koshy
2019-8-1
KALYAN ACHARJYA
2019-8-1
编辑：KALYAN ACHARJYA
2019-8-1
Madhan, already ask about sizes? Have you looked on it? I did not get any clue, just do combine of frame1 and frame2, give us the results with 8x6, rest is easy.
If you want to any logical operation between result1 and frame, both must be the same.
Or
Elaborate the question with simple example?
karishma koshy
2019-8-1
Guillaume
2019-8-1
@karishma, you asked this question already and I asked for clarification. Instead of clarifying you deleted that question and reposted it with even less information.... and you get asked the same clarifications.
So,if you want help, rather than wasting everybody's time do answer the questions that you're asked and spend time explaining everything clearly.
The question that you deleted was a lot better expressed than what you've written above even though it wasn't clear. It's even less clear now.
Personally, I won't contribute anymore since my input wasn't thought worthwile.
karishma koshy
2019-8-1
采纳的回答
Jon
2019-8-1
It isn't quite clear the specifics of what you want to retrieve but for example if you wanted to get the row in frame 1 that matches row 2 in frame 2 you could use
row = row_frame1_adata(result1(:,2),:)
17 个评论
karishma koshy
2019-8-1
编辑：karishma koshy
2019-8-1
Sorry, I'm still struggling to understand what exactly you are trying to do. I am thinking though that you have some ID's for the rows in frame1, say they are just the row numbers, 1,2,...8
Then the matching ID's for each row in frame2 would be given by
[id2,~] = find(result1)
If you have one more level of indirection, and your ids for frame 1 are given by a vector, call it id1, then you could get the ids in frame 2 using
[idx,~] = find(result1)
id2 = id1(idx)
Note it is important to use two left hand arguments (as I did above) when calling find so that it returns row and column indices rather than linear indices.
If I am still not understanding what you are trying to do, then please make a simple example which gives the inputs, and desired outputs that you are looking for.
karishma koshy
2019-8-1
karishma koshy
2019-8-1
编辑：karishma koshy
2019-8-1
Here is a script which produces the results you show in your example
% example input arrays
row_frame1_data = [
999.0000 329.8325 361.1270 22.0027
999.0000 613.6074 215.8294 28.1989
999.0000 376.3128 310.3919 22.9178
999.0000 636.6237 446.4107 27.1672
999.0000 111.5548 191.3145 24.8943
999.0000 248.6901 372.9032 41.9425
999.0000 338.8193 3.1024 23.3755
999.0000 428.1734 211.9613 23.5272];
row_frame2_data = 1e3*[
1.0000 0.3298 0.3649 0.0227
1.0000 0.1120 0.1875 0.0236
1.0000 0.2532 0.3690 0.0371
1.0000 0.6146 0.2172 0.0307
1.0000 0.3789 0.3079 0.0216
1.0000 0.2600 0.0271 0.0244];
result1 = logical(...
[1 0 0 0 0 0
0 0 0 1 0 0
0 0 0 0 1 0
0 0 0 0 0 0
0 1 0 0 0 0
0 0 1 0 0 0
0 0 0 0 0 1
0 0 0 0 0 0]);
% make arrays into tables
data1 = array2table(row_frame1_data,'VariableNames',{'frame','centre_x','centre_y','radius'});
data2 = array2table(row_frame2_data,'VariableNames',{'frame','centre_x','centre_y','radius'});
% assign id's to data2
data2.id = (1:size(data2,1))';
% find row numbers in frame1 data that have matching rows in frame2 data
% (these are the rows of result1 that have a 1 in them)
iRow = find(any(result1,2));
% find row numbers in frame 2 where each match occurs
[id,~] = find(result1');
% assign these ids in data1
% rows that don't have a matching ID will be assigned NaN
data1.id = NaN(size(data1,1),1);
data1.id(iRow) = id;
% display results
disp(data1)
disp(data2)
karishma koshy
2019-8-1
Jon
2019-8-1
Very good. Glad to hear it is working.
karishma koshy
2019-8-2
编辑：karishma koshy
2019-8-2
Jon
2019-8-2
In each loop iteration you will have to assign your result to some variable (array, structure, table) that is indexed by the loop count. So, for example you could make an array of structures, let's call it S, with fields, frame, centre_x, centre_y, radius, id. At the end of each loop iteration you would then assign the results with something like:
% preallocate array of structures
numFrames = 1000
S(numFrames) = struct('frame',[],'centre_x',[],'centre_y',[],'radius',[],'id'[])
for iFrame = 1:numFrames
% body of loop where you do all of the work
% ...
% save results in output structure
S(iFrame).frame = data1.frame;
S(iFrame).centre_x = data1.centre_x;
S(iFrame).centre_y = data1.centre_y;
S(iFrame).radius = data1.radius;
S(iFrame).id = data1.id;
end
Note, that if you are doing all of the work inside of the loop, and all you care about is the final output structure, S, it is not really necessary to be creating those intermediate tables. I just used those in the example because it organized things well ,and gave a nicely formatted output with column headings. So if efficiency is a concern, you could rework the piece I gave you to do the same calculations but not bothering to put the values into the temporary tables. Alternatively, rather than using an array of structures, S, you could accumulate all of your results into a large table with an additional column indicating the frame count. You will have to work out the details for what works best for you.
karishma koshy
2019-8-2
编辑：karishma koshy
2019-8-2
Jon
2019-8-2
You could do something like:
% preallocate cell array of tables to collect output
numFrames = 1000
data = cell(numFrames,1)
for iFrame = 1:numFrames
% body of loop where you do all of the work
% ...
% save results in output table
data{iFrame} = data1;
end
% combine all of the individual tables into one large table
data = vertcat(data{:})
karishma koshy
2019-8-2
I'm not completely clear on the details of your calculation but I think you should be able to adapt the code I sent you so that it can be included in the main loop. Since you seem to be doing a mapping of ids from the n+1 frame to the nth frame you probably have to be a little careful on the total loop count. Maybe it should only go to numFrames-1 so that you don't try to calculate beyond the end of your data
karishma koshy
2019-8-2
Jon
2019-8-2
It sounds like you have a fairly clear understanding of what you want your code to do. You just need to translate your written description into MATLAB code that implements it. Just think carefully about each step you describe and I think you will be able to come up with the detailed MATLAB implementation. If you encounter some behavior that you really can't understand, or are stuck at some very specific point then ask for more help, but I think at this point you should be able to work out the details.
karishma koshy
2019-8-2
Jon
2019-8-2
Your application is quite complicated and probably is not a good place to start learning how to code. I would suggest that if you have not done so already you should first complete the free MATLAB On Ramp training,
Make sure you work your way all the way through this and don't skip any steps.
After you complete the training and come back to your problem I think you will find you will be able to code a solution.
更多回答（1 个）
Jackson Burns
2019-8-1
row_frame_data(result1)
Where row_frame_data is the 8*6 atrix of results and result1 is the logical matrix of the values you want.
4 个评论
karishma koshy
2019-8-1
编辑：karishma koshy
2019-8-1
Mark Hayworth
2019-8-1
Exactly. Why is your logical matrix not the same size as the matrix you want to extract the values from. Your logical matrix has 4 more columns than your data. Why???
karishma koshy
2019-8-1
编辑：karishma koshy
2019-8-1
Jackson Burns
2019-8-1
You will need to adjust the dimensions of your logical array to match the data.
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