I have 10 bins, and each bin contains a specific number of observations, e.g.:
a = [0,0,1,0,0,2,0,0,0,2]
I'd like to subsequently tally how many times any given pair of (non-zero) bins co-occur - based on the number of observations.
Given the above example, bin#3 = 1, bin#6 = 2 and bin#10 = 2.
This means that bin 3 and 6 co-occurred once, bin 3 and 10 co-occurred once, and bin 6 and 10 co-occurred twice (the minimum value of the pair is taken).
My desired output is a full matrix, listing every possible bin combination (columns 1-2) and the tally of what was observed (column 3):
1 2 0
1 3 0
1 4 0
1 5 0
1 6 0
1 7 0
1 8 0
1 9 0
1 10 0
2 3 0
2 4 0
2 5 0
2 6 0
2 7 0
2 8 0
2 9 0
2 10 0
3 4 0
3 5 0
3 6 1
3 7 0
3 8 0
3 9 0
3 10 1
4 5 0
4 6 0
4 7 0
4 8 0
4 9 0
4 10 0
5 6 0
5 7 0
5 8 0
5 9 0
5 10 0
6 7 0
6 8 0
6 9 0
6 10 2
7 8 0
7 9 0
7 10 0
8 9 0
8 10 0
9 10 0
Is there a short and/or fast way of doing this?
You can get all combinations of the bin numbers in many ways. I'll use combvec for ease.
Then it's relatively simple to vectorise this using min...
a = [0,0,1,0,0,2,0,0,0,2];
n = 1:numel(a);
% Use unique and sort to get rid of duplicate pairs when order doesn't matter
M = unique( sort( combvec( n, n ).', 2 ), 'rows' );
% Get rid of rows where columns 1 and 2 are equal
M( M(:,1) == M(:,2), : ) = [];
% Get the overlap count for bins
M( :, 3 ) = min( a(M), [], 2 );
Try this.
bin_output = [....];
bin_matrix = [0,0,1,0,0,2,0,0,0,2];
bin_nonzero = find(bin_matrix);
for j = 1:length(bin_nonzero);
if isequal(j,length(bin_nonzero))
break;
end
for k = (j+1):(length(bin_nonzero))
for m = 1:length(bin_output)
if isequal(bin_output(m,1),j) && isequal(bin_output(m,2),k)
bin_output(m,3) = bin_output(m,3) + min([bin_matrix(1,bin_nonzero(1,j)),bin_matrix(1,bin_nonzero(1,k))]);
end
end
end
end
I want to sum together each cell in the same position for each matrix. I have k amount of (i,j) matrices stored in MATLAB as (i,j,k) and I want to create one matrix which is the sum of all them - however the MATLAB command sums together every value in each column whereas I want to sum together each cell in the same position from each matrix.
1 3 4 3 4 0 2 4 4
0 3 1 2 7 8 0 3 1
9 0 2 0 1 2 1 2 3
I want to create a matrix that is:
1+3+2 3+4+4 4+0+4
0+2+1 3+7+3 1+8+1
9+0+1 0+1+2 2+2+3
=
6 11 8
3 13 10
10 3 7
Use a second input to sum specifying the dimension along which to sum (in your case, 3):
>> A(:,:,1) = [ 1 3 4
0 3 1
9 0 2 ];
>> A(:,:,2) = [ 3 4 0
2 7 8
0 1 2 ];
>> A(:,:,3) = [ 2 4 4
0 3 1
1 2 3 ];
>> sum(A,3)
ans =
6 11 8
2 13 10
10 3 7
I have a matrix like this one:
8
8
8
2
2
2
6
6
7
7
7
1
1
6
6
6
6
8
8
0
6
8
8
1
6
6
There are fixed patterns that always repeat. I would like to detect them. They repeat according to these rules:
Lines with 7 followed by lines with a number which can be (0, 1 or 2), followed by a 6
Lines with 8 followed by lines with a number which can be (0, 1 or 2), followed by a 6
For each one of the values on a single pattern detected (independently from the number of lines they are composed of), write in a second column a number of rank, starting from 1 and incrementing each time a new pattern in column one is detected. This would be the result:
8 1
8 1
8 1
2 1
2 1
2 1
6 1
6 1
7 2
7 2
7 2
1 2
1 2
6 2
6 2
6 2
6 2
8 3
8 3
0 3
6 3
8 4
8 4
1 4
6 4
6 4
Column 2 encodes in each line the first pattern (series of values = 1 meaning that on this line there is data related to patter 1), the second pattern (values 2) and so on...
How can I do that?
Here's a solution that only uses the "closing tags" to split the matrix into parts:
function b = replaceValues(a)
closingTag = 6;
% Find all closing tag positions
clTagPos = a(:, 1) == closingTag;
% Keep only the "last" tags and add matrix start/end positions
splitPoints = [0; find(diff(clTagPos) == -1); length(a)];
% Split matrix into cell array
acell = mat2cell(a, diff(splitPoints));
% Replace the second column of each part with the corresponding non-zero value
bcell = cellfun(#(c)[c(:, 1) ones(length(c), 1)*c(find(c(:, 2), 1), 2)], acell, 'UniformOutput', 0);
% Convert back to matrix
b = cell2mat(bcell);
end
Example input-output in Matlab:
a =
8 0
8 0
8 0
2 1
2 1
2 1
6 0
6 0
7 0
7 0
7 0
1 2
1 2
6 0
6 0
6 0
6 0
8 0
8 0
0 3
6 0
8 0
8 0
1 4
6 0
6 0
>> b = replaceValues(a)
b =
8 1
8 1
8 1
2 1
2 1
2 1
6 1
6 1
7 2
7 2
7 2
1 2
1 2
6 2
6 2
6 2
6 2
8 3
8 3
0 3
6 3
8 4
8 4
1 4
6 4
6 4
I would like to select some numbers in a MATLAB matrix which have values greater than 4 and set them equal to zero.
For example:
A=[5 6 1 3 4 9 2 8 3];
Now, replace all values greater than 4 with zeros and store as a new matrix A1:
A1=[0 0 1 3 4 0 2 0 3];
You might want to try something like this:
A(A>4)=0
Here it is:
>> A=[5 6 1 3 4 9 2 8 3]
A =
5 6 1 3 4 9 2 8 3
>> A(A>4)=0
A =
0 0 1 3 4 0 2 0 3
It was hard to phrase the question, but here's an example of what I'm looking for:
1 2 3 4
2 1 1 1
2 2 3 1
0 0 0 0
and in column one, I add all the value of all of the first three rows and save it to the third and so on, so that it becomes:
1 2 3 4
2 1 1 1
2 2 3 1
5 5 7 6
I think you can use sum:
octave:23> m = [1 2 3 4; 2 1 1 1; 2 2 3 1; 0 0 0 0]
m =
1 2 3 4
2 1 1 1
2 2 3 1
0 0 0 0
octave:24> m(length(m), :) = sum(m)
m =
1 2 3 4
2 1 1 1
2 2 3 1
5 5 7 6