could anyone help me to get C from A and B

If A =

       1     2     3     4     5
      11    12    13    14    15
       6     7     8     9    10
      21    22    23    24    25
      26    27    28    29    30

B =

       0     0    41     0     0
      45     0     0     0     0
       0    43     0     0     0
       0     0     0    42     0
       0     0     0     0    44

and 
C =

       0     0    41     4     0
      45    12     0     0    15
       6    43     0     0    10
       0     0    23    42     0
      26    27     0     0    44

How to obtain C from A and B. the example mentioned here is for (5,5) if it is for (50,100) how it can be done?

[Birdman]

What is your condition for obtaining? There is not a certain pattern or something else for achieving C from A and B.

[Prabha Kumaresan]

In the example mentioned i am clustering (row 1, row 4) and (row2,row3,row5) from B . As a result of clustering (row1,row4) from B, which has values of(41 in(1,3),42 in(4,4)) gets modified into (41 in (1,3) and 4(from A) in (1,4),23(from A) in (4,3) and 42 in (4,4)).the same condition applies to clustering of ((row2,row3,row5))

Answer 1

[Rik]

Let me start off by saying you described it very poorly (and formatting your comment as code doesn't help).

What seems to be the goal is adding values to B. The rule for this is that in groups of rows, the entire column must be either 0 or contain a value. If B on that position is equal to 0, the value is taken from A.

For rows 1 and 4:

cluster=[0     0    41     0     0;
         0     0     0    42     0];
non_0=  sum(cluster);
non_0=repmat(non_0,2,1);
A_part=[1     2     3     4     5;
        21    22    23    24    25];
new_cluster=cluster;
new_cluster(non_0 & cluster==0)=A_part(non_0 & cluster==0);

So now the question is how to generalize this to inputs of rows. Personally, I think you should be able to use this code a basis to write your own code for arbitrary row groups. The only thing you need to write is how to extract the clusters and put them back.

[Prabha Kumaresan]

Thanks. Could you help me to write for arbitrary row groups thereby extracting the clusters.

[Prabha Kumaresan]

Could you please help me to have an arbitrary row groups by extracting the clusters and putting them back as i was struggling from morning.

[Rik]

What did you try? You are hopefully aware you can index matrices with a syntax like Y=X([1 3],:);?