A problem with using generalized code

UPDATE:

I think I found what is the cause of this problem in fact in the last code that I wrote to this question, in this line

Cnew{r,m}=cell2table(C{r,m}.station_name); % input names under the "station_name" variable of your old tables into the new cell array based on their indexed locations

It gets Cnew based on station_name. station_name in C was different names but in Cgrid all station_names are same each other. So I think this line should modify but I don't know-how.

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Hello all,

I have a problem, I checked everything but I can't find whats wrong. I want to use the function that writes for me in my previous question for new input (Cgrid) against C (in the previous question). The function gave me the right answer when I run it using C (previous question attached file) but it gives me repeated answers when I try to run it using Cgrid as input. I write my issue here and I write my codes too:

I wanted to run this code ( I call it N_SPI in the rest of this question) below for each precip in the tables that stored in Cgrid and save the results in another cell named CgridSPI.

 % The name of this code is N_SPI
% Source code: https://www.mathworks.com/matlabcentral/fileexchange/51080-nonparametric-standardized-precipitation-index-spi
% this code calculates SPI 1, 3, 6, 12, 24, 48 months for a given station.

td = Cgrid{1,1}.rrr24; % get rrr24 of first station_name I want do it for all station_name's rrr24
Date = Cgrid{1,1}.date % date is constant for all station_name

sc_vect=[1 3 6 12 24 48]; % a set including all values for iterations
% sc: scale of the index (>1, e.g., 3-month SPI or SSI)
n=length(td);
SI=zeros(n,numel(sc_vect)); % columns correspond to values in sc_vect
% iterate over sc_vect
for p=1:numel(sc_vect)
    sc = sc_vect(p);
    
    %For some grid, no observation exist.
    if length(td(td>=0))/length(td)~=1
        SI(n,p)=nan;
    else
        % Obtain the prcp and smc for the specified time scale and
        % compute the standarized drought index (for SPI and SSI)
        SI(1:sc-1,p)=nan;
        
        A1=[];
        for i=1:sc,
            A1=[A1,td(i:length(td)-sc+i)];
        end
        Y=sum(A1,2);
        
        % Compute the SPI or SSI
        
        nn=length(Y);
        SI1=zeros(nn,1);
        
        for k=1:12
            
            d=Y(k:12:nn);
            %compute the empirical probability
            nnn=length(d);
            bp=zeros(nnn,1);
            
            for i=1:nnn
                bp(i,1)=sum(d(:,1)<=d(i,1));
            end
            
            y=(bp-0.44)./(nnn+0.12);
            
            SI1(k:12:nn,1)=y;
        end
        
        SI1(:,1)=norminv(SI1(:,1));
        %output
        SI(sc:end,p)=SI1;
    end
end
CgridSPI = array2table(SI);
CgridSPI.Properties.VariableNames = {'SPI_1month' 'SPI_3month' 'SPI_6month'...
    'SPI_12month' 'SPI_24month' 'SPI_48month'};

So thanks to helping by fred ssemwogerere in this question I used this function below to use the above code for all my tables in Cgrid.

function SI = myfunction(Cn,rnum,colnum,tcol) % save this as a functionfile with filename: "myfunction.m"
%Summary of "myfunction"
% SI = output
% Cn = Cell array storing all tables
% rnum = row index of table in cell array
% colnum = column index of table in cell array
% tcol = column number of table variable ("rrr24") on which you are doing the computations
td = table2array(Cn{rnum, colnum}(:,tcol)); % example for C{1, 1}
n=numel(td);
sc_set= [3,6,12,24]; 
SI=zeros(n,length(sc_set)); 
for q = 1:length(sc_set)
  sc = sc_set(q); % I have replaced "k" with "q" on this line
  if numel(td(td>=0))/numel(td)~=1
      SI(n,q)=nan;
  else
      SI(1:sc-1,q)=nan;
      A1=[];
      for i=1:sc
          A1=[A1,td(i:numel(td)-sc+i)]; %#ok<AGROW>
      end
      Y=sum(A1,2);
      nn=numel(Y);
      SI1=zeros(nn,1);
      for k=1:12
          d=Y(k:12:nn);
          nnn=numel(d);
          bp=zeros(nnn,1);
          for i=1:nnn
              bp(i,1)=sum(d(:,1)<=d(i,1));
          end
          y=(bp-0.44)./(nnn+0.12);
          SI1(k:12:nn,1)=y;
      end
      SI1(:,1)=norminv(SI1(:,1));
      %output
      SI(sc:end,q)=SI1;
  end
end
end

So then I used this below to achieve my outputs:

Cnew=cell(1,size(Cgrid,2)); % pre-allocating your new array
for r=1:size(Cgrid,1)
    for m=1:size(Cgrid,2)
        SI{r,m}= myfunction(Cgrid,r,m,4);% On this line, "4" is the column index of "precip" (your table variable)
        Cnew{r,m}=cell2table(Cgrid{r,m}.model_name); % input names under the "station_name" variable of your old tables into the new cell array based on their indexed locations
        Cnew{r,m}.Output=SI{r,m}; % Add column variable, "Output" holding computed values to each table in the new cell array based on their indexed positions
        Cnew{r,m}.Properties.VariableNames{1}='model_name'; % variable name for first column of each table
    end
end

This code gives me correct answers when I run it using my previous question attached data but when here I want to run it with Cgrid, I saw that all results for all tables are the same (repeated, all is 2.02).

To check that issue I run N_SPI code manually for some cell in Cgrid and saw that everything is okay and I haven't any similar results in CgridSPI , I don't know why I get the same answer for all tables when I use Cgrid.

Thank you in advance

Answer 1

[fred ssemwogerere]

Hello, the problem stems from the value of your column index; "4". You should be indexing column "5" instead on line 4 of the last code above. Column index "4" is for position (latitude). Additionally, please edit the function file "myfunction" on line 4 (without counting commented lines) to:

sc_set= [1,3,6,12,24,48];
% this includes additional inputs for periods that you are making the computations

[BN]

Thank you so much. My problem fixed.