function mat2rwl(data,years,seriesnames,filename)

% MAT2RWL  Write raw ring measurements to Tucson format
%
%    mat2rwl(data,years,seriesnames,filename)
%
% This function writes a matrix into a Tucson decadal format
% ASCII file.  Missing values should be 'NaN'.  

[r,nseries] = size(data);
maxYear = max(years); minYear = min(years);
fid = fopen(filename,'wt');


for i=1:nseries
 thisSeriesLength = length(data(~isnan(data(:,i)),i));
 
 % starting point and first decade
 startPointer = min(find(~isnan(data(:,i))));
 thisStartYear = years(min(find(~isnan(data(:,i)))));
 firstDecade = ceil(thisStartYear/10)*10;
 firstDecadePointer = find(years==firstDecade);

 endPointer = max(find(~isnan(data(:,i))));
 thisEndYear = years(max(find(~isnan(data(:,i)))));

 lastDecade = floor(thisEndYear/10)*10;
 lastDecadePointer = find(years==lastDecade);

 % first (incomplete) line for a given tree ...
 fprintf(fid, '%-8s%4i%6i%6i%6i%6i%6i%6i%6i%6i%6i%6i\n',seriesnames{i}(:,:),[thisStartYear data(startPointer:firstDecadePointer-1,i)']);   %write data to file
 fprintf(fid,'\n')

 % ... complete decades for that tree ...
 interveningDecades = [firstDecade:10:lastDecade]';
  for j=1:length(interveningDecades)-1;
    P1 = find(years==interveningDecades(j))
    P2 = find(years==interveningDecades(j+1))-1
    [i j P1 P2]
    fprintf(fid, '%-8s%4i%6i%6i%6i%6i%6i%6i%6i%6i%6i%6i\n',seriesnames{i}(:,:),[interveningDecades(j) data(P1:P2,i)']);   %write data to file
  
  end

% ... last (incomplete) line for that tree ...
 fprintf(fid, '%-8s%4i%6i%6i%6i%6i%6i%6i%6i%6i%6i%6i\n',seriesnames{i}(:,:),[lastDecade data(lastDecadePointer:endPointer,i)' 999]);   %write data to file
 fprintf(fid,'\n')

end


fclose(fid);   % close file   



close file