Splitting a matrix in subsets??

Dear experts, I have a scenario matrix from which I would like to generate a binary tree, the binary tree structure matrix is as follow:

if true
  % code
    M= [8 25 25 25 25 25;
        8 25 36 36 36 36;
        8 25 25 15 15 15;
        8 25 36 50 50 50;
        8 25 25 10 10  10;
        8 25 25 6 6 6;
        8 25 36 70 70 70;
        8 25 25 3 3 3];
end

where 1st and 2nd row are mother scenarios and the rest are the branching scenarios. I would like to seperate this matrix to these two scenario that which rows is a subset of which mother row. so that the end result should be

if true
 %
M1 = [8 25 25 25 25 25;
      8 25 25 15 15 15;
      8 25 25 10 10 10;
      8 25 25 6 6 6; 
      8 25 25 3 3 3];
%
M2 = [8 25 36 36 36 36;
      8 25 36 50 50 50; 
      8 25 36 70 70 70];

end

[Geoff Hayes]

Usman - in your example, M1 and M2 have three rows in common. How are you determining which row belongs to which mother row?

[Usman Ali]

Ohhhh my Bad :( , let me correct it. Actually the M1 includes all the branches of [8 25 25 25 25 25] and M2 includes all the branches connected to [8 25 36 36 36 36].

if true
  % code
 M1 = [8 25 25 25 25 25; 8 25 25 15 15 15;
 8 25 25 10 10  10; 8 25 25 6 6 6;
 8 25  25 3 3 3];

%
  M2 = [8 25 36 36 36 36; 8 25 36 50 50 50; 
  8 25 36 70 70 70];
end

Answer 1

[Iain]

 M = [8 25 25 25 25 25; 8 25 36 36 36 36; 8 25 25 15 15 15;
   8 25 36 50 50 50; 8 25 25 10 10  10; 8 25 25 6 6 6;
   8 25 36 70 70 70; 8 25  25 3 3 3];

 M1 = M(1:2:(end-1),:);
 M2 = M(2:2:(end),:);

[Iain]

Change the 1:2:end-1 etc. with the appropriate list.

[Usman Ali]

does not solves my problem, Sorry I do not get it, what shall be an appropriate list in the above case??

[Iain]

To match your example:

The first list (for M1) is: [1 3 5 6 8]

The second list (for M2) is: [2 4 5 6 8]

Why that matches your example, I do not know.

[Usman Ali]

I guess your ans is some what manual. the posted matrix is just an example, in real i have a very big matrix of [7000 x 50]. what if the order of rows is changed that's why I need some automatic solution that should compare the selected rows with mother row and splitt them into different subsets.

[Iain]

You need some logic that fills in the lists.

If the first list is defined by rows that have 25 in the 3rd column, then the first list is:

 list1 = find(M(:,3) == 25);

Answer 2

[Adam]

M1 = M( M(:,3) == 25,:)
M2 = M( M(:,3) == 36,:)

would seem to do the job in that case though that assumes that column 3 contains the value that distinguishes the two branching paths, irrespective of the values in the other columns.