function data=readbin(fname,nrow)
fid=fopen(fname,'rb');
if (fid==-1)
disp('file not found');
data=[];
return;
end
data=fread(fid,[nrow inf],'double');
vr_a=fread(fid,1,'double');
if (~isempty(vr_a))
disp('readbin: nrow may be wrong!');
end
fclose(fid);