how can I get the max of the values between NaN's in an array

I have an array like this one:

T = [NaN NaN; ...
1 3; 
2 4; 
5 6; 
8 7; 
NaN NaN; 
NaN NaN; 
4 5; 
6 7;  
NaN NaN; 
NaN NaN; 
1 2; 
2 4; 
5 6; 
NaN NaN];

Now I'd like to add the columns of the values between the Nan's and get the max values of the sums. So the outcome in this case would be:

max = [15; 13; 11]

I tried this:

NaNloc=isnan(T);
ind=find(NaNloc(:,1)); 

for i=1:(length(ind)-1) 

      if ind(i+1)-ind(i) >1
          patloc=[ind(i) ind((i+1))];

          patarray=patloc(1):1:patloc(2);

          for j=patarray(1):patarray(length(patarray))

              a=T(j,:);
              f=a(1)+a(2);
              fsave(j-patloc(1)+1,:)=f; 

          end

    max(fsave)

      end  
  end

but I get the outcome: 15 15 11

Answer 1

[Azzi Abdelmalek]

T = [NaN NaN; 1 3; 2 4; 5 6; 8 7; NaN NaN; NaN NaN; 4 5; 6 7; NaN NaN; NaN NaN; 1 2; 2 4; 5 6; NaN NaN;4 5];
h=[1;isnan(T(:,1)) ;1]';
out=arrayfun(@(x,y) max(sum(T(x:y,:),2)),strfind(h,[1 0]),strfind(h,[0 1])-1)

[Matt J]

I don't get the correct answer from this. I get,

15    13    11     9

[Joanie]

That's because Azzi added 4 5 at the end of T :)

Answer 2

[Matt J]

    T=sum(T,2);
    lims=reshape(find(isnan(T)),2,[]);
      n=size(lims,2);

    result=nan(1,n);
    for i=1:n

      result(i)=max(T(lims(1,i)+1:lims(2,i)-1));

    end

[Joanie]

Is there a way to make the code I made work? Because in my data there are some other things going on in this loop:

for j=patarray(1):patarray(length(patarray))
            a=T(j,:);
            f=a(1)+a(2);
            asave(j-patloc(1)+1,:)=a;
            fsave(j-patloc(1)+1,:)=f; 
end

[Matt J]

I don't fully understand your original code, but here is how I would extract each individual block of T

   if ~isnan(T(1))
    T=[nan,nan;T];
   end

   if ~isnan(T(end))
    T=[T;nan,nan];
   end   

    nanloc=find(isnan(T(:,1)));

    for i=1:length(nanloc)-1

      a=nanloc(i);  
      b=nanloc(i+1);
      if b-a==1, 
          continue;
      else
       a=a+1;b=b-1;     
      end

      Tblock = T(a:b,:), %current block
    end

[Joanie]

Thank you I can work with this!

Answer 3

[Andrei Bobrov]

l = ~isnan(T(:,1));
k = [l(1);diff(l)] == 1;
ii = cumsum(k);
z = (1:size(T,1))';
out = accumarray(ii(l),z(l),[],@(x)max(sum(T(x,:),2)));