Reduction of a matrix

Dear MATLAB Experts,

I have encountered a problem in my research seems to be very tricky to me. Assume there is a matrix of size n*2 and the reduced form is needed. For simplicity let M represents our matrix. For each row of i, I need to calculate the difference of

M(i+1,1) - M(i,2);

and if the difference was smaller than a threshold value of 100, the the row numbers i and i+1 will be combined as a single row with the following elements:

M(i,1)    M(i+1,2).

Otherwise, both rows i and i+1 should be kept. The output of such a code is my desired reduced matrix. For example consider matrix M as

M = [5     180
     200   300
     330   600 
     1000  1400
     1430  1500]

The code firstly combine the first two rows since they meet the criterion explained above;

M1 = [5   300
      330 600
      1000 1400
      1430 1500]

In the second step, the code will combine the first two rows of the output matrix of step 1, i.e. M1 as follows

M2= [5  600
     1000 1400
     1430 1500]

This procedure continues so far so forth until we get the final desired output that is,

 M_RED = [5  600
          1000 1500]

I wonder if you can kindly help me figure it out. Any helps will be appreciated and I thank you for the time you take to assist me.

PS: What I actually need to get is the M_RED and I really do not care what the M1 and M2 and other matrices look alike. I just introduced them for the sake of better illustration.

Answer 1

[Homayoon]

This is what I came up with but I am looking for a more sophisticated approach.

b=0
for i=1:(size(M,1)-1)
if M(i+1,1)-M(i,2)>101
b=b+1; 
end
end
z = zeros(b+1 ,2); %reduced matrix
c=1;
z(1)=M(1);
z(2*(b+1))=M(size(M,1)*2);
for i=1:4
if M(i+1,1)-M(i,2)>101
z(c,2) = M(i,2);
z(c+1,1)=M(i+1,1);
c=c+1;
end
end

This works perfectly but as I said am looking for something more sophisticated.