Why the EOF gives the total of 99.9

clear all; clc;

data= load('north_x_y_lat_lon');
datacoord = reshape(data, 361,361,4);
lat = squeeze(datacoord(:,:,3));
long = squeeze(datacoord(:,:,4));
years = 1979:2015;

long1 = long(1:10:end,1:10:end);
lat1 = lat(1:10:end,1:10:end);

rlong = long*pi/180.;
rlat = lat*pi/180.;

load nsidc_sid_1979_2014.mat 

% change the matrix to the size 36*361*361 (required for map2mat)
M = [];
for i = 1:36,
    M(i,:,:) = mm_r(:,:,i);
end

%take every 10th pixel to make the calculation easier
g = M(:,1:10:end,1:10:end);

%Replace NaN's with zeros
g(isnan(g)) = 0;

%change it into (time*pt)
G = map2mat(ones(size(g,2),size(g,3)),g);

N = 2;
for method = 1:4;
    % method=1;
    [E,pc,expvar] = caleof(G,N,method);  

      eof = mat2map(ones(size(g,2),size(g,3)),E);

      figure(method);clf;iw=1;jw=N+1;
      set(gcf,'MenuBar','none');
      posi = [576 0 710 205];
      set(gcf,'position',[posi(1) (method-1)*250+50 posi(3) posi(4)]);

          for i=1:iw*jw
            if i<= iw*jw-1

                C = squeeze(eof(i,:,:));
                subplot(iw,jw,i);

                m_proj('Stereographic','lat',90,'long',300,'radius',35,'rect','on')
                [cs,h] = m_contourf(long1,lat1,C,50,'linestyle','none');
                colorbar;
      %           clabel(cs,h); 
                m_grid('linewi',1,'tickdir','out',...
                    'xtick', [],'ytick',[])
                m_coast('patch',[.6 .6 .6],'edgecolor','k')
                title(strcat('EOF:',num2str(i),'/',num2str(expvar(i)),'%'));
                axis square;
                %caxis([cont(1) cont(end)]);

            else
                subplot(iw,jw,iw*jw);
                plot(pc');
                grid on
                xlabel('time')
                title('PC')
                legend(num2str([1:N]'),2);
                box on

            end %if

          end %for i

          title(strcat('METHOD:',num2str(method)));

end %for method

• I have two questions regarding the caleof function-1. Why the method 1 and 3 gives the same result and method 2 and 4 gives the same result2. when i am trying to change the N to 2,3 4.. every time the total of the respective PC's is 99.9%*

Answer 1

[Spencer Chen]

Running error, perhaps.

caleof is not a built-in Matlab function. You are probably using the File Exchange toolbox:

https://www.mathworks.com/matlabcentral/fileexchange/17915-pcatool?focused=5095377&tab=function

Maybe you should ask the question there.

Answer 2

[Chad Greene]

This line in caleof is the culprit:

expvar(iN)=fix((dsum(iN)*100/sum(dsum))*10)/10;

The fix function rounds down. The part that multiplies by 10 and later divides by 10 is a way of rounding to down to the nearest 0.1 percent. It is probably better to replace that line with:

expvar(iN)=dsum(iN)*100/sum(dsum);