Comparing value in m x n matrices to find its index

Hi, I have one set of data that I need to compare it with different size of data. So, as it stated in this code below, the threshold will be 3, 3.5, 4, 4.5 ..... I have to compare each threshold with all available data in variable GtrecMRCG2 then get its index. after all data compared, I need to check it with remaining threshold in variable thresholdVAR.

I wrote this based on my understanding. but it doesn't work because the dimension is mismatched. Thank you so much and big appreciation to those who want to give me advises. :)

threshold = 3;
thresholdVAR=[threshold 0 0 0 0 0 0 0 0];
GtrecMRCG2= [ 5 8 9 6 2 5 2 4 6 3 8 9 11];
for ii=1:9

    thresholdVAR(ii+1:end)= thresholdVAR(ii)+ 0.5;
  end

for idxm=1:length(thresholdVAR)
for idxn = 1:length(GtrecMRCG2)
idxalarmMRCG (1:length(thresholdVAR),1:length(GtrecMRCG2))= find(GtrecMRCG2(idxm,idxn)>=thresholdVAR(idxm,idxn));
end
end

[Jan]

Please post the complete error message.

Your description is a little bit vague and the code does not run. Therefore I doubt that the given information allows to solve the problem in the way you want.

In the first loop you overwrite the elements multiple times. Perhaps all you want cumsum?

[Tifani Utami]

yes I am trying to construct cumsum which does not come from matlab function. the code above, is just an example. I'm working with larger and dynamic size data. I found this solution in other discussion which kind of similar to my problem. I've tried to modified them and still

??? Error using ==> lt
Matrix dimensions must agree.

Error in ==> coba2 at 19
            is_greater_equal = find( thresholdVAR(idxm:sza(1),idxn:sza(2)) <
            GtrecMRCG2(1:sza(1),1:sza(2)));

code:

threshold = 3;
thresholdVAR=[threshold 0 0 0 0 0 0 0 0];
GtrecMRCG2= [ 5 8 9 6 2 5 2 4 6 3 8 9 11];
for ii=1:9
thresholdVAR(ii+1:end)= thresholdVAR(ii)+ 0.5;
end
    sza = size( thresholdVAR );
  for idxm=1:length(thresholdVAR)
    for idxn = 1:length(GtrecMRCG2)
            is_greater_equal = find( thresholdVAR(idxm:sza(1),idxn:sza(2)) <  GtrecMRCG2(1:sza(1),1:sza(2)));
    end
  end

[CS Researcher]

Not exactly sure what you are trying to achieve but you should see the line with the code:

find( thresholdVAR(idxm:sza(1),idxn:sza(2)) <  GtrecMRCG2(1:sza(1),1:sza(2)));

Your thresholdVAR and GtrecMRCG2 are not 2D matrices. They both are 1D vectors.

Also, you don't need a loop to initialize the thresholdVAR. You can just do this:

thresholdVAR = 3:0.5:7;

[Tifani Utami]

example first value of threshold. when threshold is 3, compare it with the value which in GtrecMRCG2 variable. find the index containing value that greater equal than GtrecMRCG2.

is_greater_equal will be [ 1 2 3 4 6 8 9 10 11 12 13]

then move to the next threshold which is 3.5

is_greater_equal = [ 1 2 3 4 6 8 9 10 11 12 13]

the process will keep going until all value which in GtrecMRCG2 compared with last threshold. my question is how to manipulate the output or to construct a new matrices as a result of comparison between two different matrices length.

Answer 1

[Ilham Hardy]

Something like this?

thresholdVAR = 3:0.5:7;
GtrecMRCG2= [ 5 8 9 6 2 5 2 4 6 3 8 9 11];

% preallocate
DesMat = zeros(length(thresholdVAR),length(GtrecMRCG2));

for oneL = 1:length(thresholdVAR)
    [r,c,v] = find(GtrecMRCG2>thresholdVAR(oneL));

      DesMat(oneL,c) = GtrecMRCG2(c);
end

[Tifani Utami]

thanks a lot. I finally able to use the result to find its average value.