nested loop will not enter second iteration

Hi,

Below is my code. For each month of each year I am trying to get the average and std for a set of values. The first iteration works for the first year. But then it does not continue. Can someone tell me where the problem is.

[M,ia,ic] = unique(CO2_FFD(:,2)); %find unique years, M = unique year, ia = row with unique year

m=[1;2;3;4;5;6;7;8;9;10;11;12];%set an array for 12 months

CO2_YM_averages = zeros(length(M)*12,2); %array for averages & std's, size of year*12months

for i=1:length(M)

yrows = find(M(i)==CO2_FFD(:,2)); %find rows where year is equal to M(i)

for j=1:length(m)

mrows=find(CO2_FFD(yrows,3)== m(j));%find rows where month = m(i)

CO2_YM_averages(j,1) = mean(CO2_FFD(mrows,8)); %average data for each month

CO2_YM_averages(j,2) = std(CO2_FFD(mrows,8)); %std data for each month

end

end

[Image Analyst]

Undefined function or variable 'CO2_FFD'.

Please supply it so we can run your code.

[Jennifer Walker]

It is an array of >30,000 rows but it is structured as

CO2_FFD = [ serial date, YY, MM, DD, HR, MIN, SEC, VALUE]

[Jennifer Walker]

I can see that i is not incrementing when the code stops >> i

i =

     1

[Jennifer Walker]

here is some sample data:

CO2_FFD = [0 2000 1 1 0 0 0 340 ; 0 2000 1 2 0 0 0 380 ; 0 2000 2 3 0 0 0 280 ; 0 2000 2 4 0 0 0 450 ; 0 2000 3 5 0 0 0 330 ; 0 2000 3 6 0 0 0 450 ; 0 2000 4 7 0 0 0 380 ; 0 2000 4 8 0 0 0 290 ; 0 2000 5 9 0 0 0 340 ; 0 2000 5 10 0 0 0 380 ; 0 2000 6 11 0 0 0 280 ; 0 2000 6 12 0 0 0 450 ; 0 2000 7 13 0 0 0 330 ; 0 2000 7 14 0 0 0 450 ; 0 2000 8 15 0 0 0 380 ; 0 2000 8 16 0 0 0 290 ; 0 2000 9 17 0 0 0 340 ; 0 2000 9 18 0 0 0 380 ; 0 2000 10 19 0 0 0 280 ; 0 2000 10 20 0 0 0 450 ; 0 2000 11 21 0 0 0 330 ; 0 2000 11 22 0 0 0 450 ; 0 2000 12 23 0 0 0 380 ; 0 2000 12 24 0 0 0 290 ; 0 2001 1 25 0 0 0 340 ; 0 2001 1 26 0 0 0 380 ; 0 2001 2 27 0 0 0 280 ; 0 2001 2 28 0 0 0 450 ; 0 2001 3 29 0 0 0 330 ; 0 2001 3 30 0 0 0 450 ; 0 2001 4 1 0 0 0 380 ; 0 2001 4 2 0 0 0 290 ; 0 2001 5 3 0 0 0 340 ; 0 2001 5 4 0 0 0 380 ; 0 2001 6 5 0 0 0 280 ; 0 2001 6 6 0 0 0 450 ; 0 2001 7 7 0 0 0 330 ; 0 2001 7 8 0 0 0 450 ; 0 2001 8 9 0 0 0 380 ; 0 2001 8 10 0 0 0 290 ; 0 2001 9 11 0 0 0 340 ; 0 2001 9 12 0 0 0 380 ; 0 2001 10 13 0 0 0 280 ; 0 2001 10 14 0 0 0 450 ; 0 2001 11 15 0 0 0 330 ; 0 2001 11 16 0 0 0 450 ; 0 2001 12 17 0 0 0 380 ; 0 2001 12 18 0 0 0 290 ; 0 2002 1 19 0 0 0 340 ; 0 2002 1 20 0 0 0 380 ; 0 2002 2 21 0 0 0 280 ; 0 2002 2 22 0 0 0 450 ; 0 2002 3 23 0 0 0 330 ; 0 2002 3 24 0 0 0 450 ; 0 2002 4 25 0 0 0 380 ; 0 2002 4 26 0 0 0 290 ; 0 2002 5 27 0 0 0 340 ; 0 2002 5 28 0 0 0 380 ; 0 2002 6 29 0 0 0 280 ; 0 2002 6 30 0 0 0 450 ; 0 2002 7 31 0 0 0 330 ; 0 2002 7 32 0 0 0 450 ; 0 2002 8 33 0 0 0 380 ; 0 2002 8 34 0 0 0 290 ; 0 2002 9 35 0 0 0 340 ; 0 2002 9 36 0 0 0 380 ; 0 2002 10 37 0 0 0 280 ; 0 2002 10 38 0 0 0 450 ; 0 2002 11 39 0 0 0 330 ; 0 2002 11 40 0 0 0 450 ; 0 2002 12 41 0 0 0 380 ; 0 2002 12 42 0 0 0 290 ]

Answer 1

[Image Analyst]

I get 3 tierations for i. Here is my code:

% here is some sample data:
CO2_FFD = [0  2000  1  1  0  0  0  340  ;
0  2000  1  2  0  0  0  380  ;
0  2000  2  3  0  0  0  280  ;
0  2000  2  4  0  0  0  450  ;
0  2000  3  5  0  0  0  330  ;
0  2000  3  6  0  0  0  450  ;
0  2000  4  7  0  0  0  380  ;
0  2000  4  8  0  0  0  290  ;
0  2000  5  9  0  0  0  340  ;
0  2000  5  10  0  0  0  380  ;
0  2000  6  11  0  0  0  280  ;
0  2000  6  12  0  0  0  450  ;
0  2000  7  13  0  0  0  330  ;
0  2000  7  14  0  0  0  450  ;
0  2000  8  15  0  0  0  380  ;
0  2000  8  16  0  0  0  290  ;
0  2000  9  17  0  0  0  340  ;
0  2000  9  18  0  0  0  380  ;
0  2000  10  19  0  0  0  280  ;
0  2000  10  20  0  0  0  450  ;
0  2000  11  21  0  0  0  330  ;
0  2000  11  22  0  0  0  450  ;
0  2000  12  23  0  0  0  380  ;
0  2000  12  24  0  0  0  290  ;
0  2001  1  25  0  0  0  340  ;
0  2001  1  26  0  0  0  380  ;
0  2001  2  27  0  0  0  280  ;
0  2001  2  28  0  0  0  450  ;
0  2001  3  29  0  0  0  330  ;
0  2001  3  30  0  0  0  450  ;
0  2001  4  1  0  0  0  380  ;
0  2001  4  2  0  0  0  290  ;
0  2001  5  3  0  0  0  340  ;
0  2001  5  4  0  0  0  380  ;
0  2001  6  5  0  0  0  280  ;
0  2001  6  6  0  0  0  450  ;
0  2001  7  7  0  0  0  330  ;
0  2001  7  8  0  0  0  450  ;
0  2001  8  9  0  0  0  380  ;
0  2001  8  10  0  0  0  290  ;
0  2001  9  11  0  0  0  340  ;
0  2001  9  12  0  0  0  380  ;
0  2001  10  13  0  0  0  280  ;
0  2001  10  14  0  0  0  450  ;
0  2001  11  15  0  0  0  330  ;
0  2001  11  16  0  0  0  450  ;
0  2001  12  17  0  0  0  380  ;
0  2001  12  18  0  0  0  290  ;
0  2002  1  19  0  0  0  340  ;
0  2002  1  20  0  0  0  380  ;
0  2002  2  21  0  0  0  280  ;
0  2002  2  22  0  0  0  450  ;
0  2002  3  23  0  0  0  330  ;
0  2002  3  24  0  0  0  450  ;
0  2002  4  25  0  0  0  380  ;
0  2002  4  26  0  0  0  290  ;
0  2002  5  27  0  0  0  340  ;
0  2002  5  28  0  0  0  380  ;
0  2002  6  29  0  0  0  280  ;
0  2002  6  30  0  0  0  450  ;
0  2002  7  31  0  0  0  330  ;
0  2002  7  32  0  0  0  450  ;
0  2002  8  33  0  0  0  380  ;
0  2002  8  34  0  0  0  290  ;
0  2002  9  35  0  0  0  340  ;
0  2002  9  36  0  0  0  380  ;
0  2002  10  37  0  0  0  280  ;
0  2002  10  38  0  0  0  450  ;
0  2002  11  39  0  0  0  330  ;
0  2002  11  40  0  0  0  450  ;
0  2002  12  41  0  0  0  380  ;
0  2002  12  42  0  0  0  290  ]
[M,ia,ic] = unique(CO2_FFD(:,2)); %find unique years, M = unique year, ia = row with unique year
m=[1;2;3;4;5;6;7;8;9;10;11;12];%set an array for 12 months
CO2_YM_averages = zeros(length(M)*12,2); %array for averages & std's, size of year*12months
for i=1:length(M)  
  fprintf('i = %d\n', i);
  yrows = find(M(i)==CO2_FFD(:,2)); %find rows where year is equal to M(i)  
  for j=1:length(m)    
  fprintf('    j = %d\n', j);
    mrows=find(CO2_FFD(yrows,3)== m(j));%find rows where month = m(i)    
    CO2_YM_averages(j,1) = mean(CO2_FFD(mrows,8)); %average data for each month    
    CO2_YM_averages(j,2) = std(CO2_FFD(mrows,8)); %std data for each month    
  end  
end

and here is the results:

i = 1
    j = 1
    j = 2
    j = 3
    j = 4
    j = 5
    j = 6
    j = 7
    j = 8
    j = 9
    j = 10
    j = 11
    j = 12
i = 2
    j = 1
    j = 2
    j = 3
    j = 4
    j = 5
    j = 6
    j = 7
    j = 8
    j = 9
    j = 10
    j = 11
    j = 12
i = 3
    j = 1
    j = 2
    j = 3
    j = 4
    j = 5
    j = 6
    j = 7
    j = 8
    j = 9
    j = 10
    j = 11
    j = 12

Why do you say there is only one iteration for i???

[Jennifer Walker]

when I type i into the command line it returns i=1.

if you look at CO2_YM_averages where the averages and std's should be saved, it only does the first year, so I thought it was not entering the first loop a second time

[Jennifer Walker]

Oh I see my problem now, I was rewriting over my rows by calling j in every loop. I fixed it using this:

[M,ia,ic] = unique(CO2_FFD(:,2)); %find unique years/month, M = unique year/month, ia = row with unique year/month m=[1;2;3;4;5;6;7;8;9;10;11;12];%array for 12 months CO2_YM_averages = zeros(length(M)*12,2); %array for averages, size of year/month for i=1:length(M) yrows = find(M(i)==CO2_FFD(:,2)); %find rows where year is equal to M(i) for j=1:length(m) %j=j+1; mrows=find(CO2_FFD(yrows,3)== m(j));%find rows where month = m(i) r = (i-1)*12+j; CO2_YM_averages(r,1) = mean(CO2_FFD(mrows,8)); %average data for each day CO2_YM_averages(r,2) = std(CO2_FFD(mrows,8)); end end

[Jennifer Walker]

Thank you so much for your help! Without the print function I would have never figured it out. Thats a great trick!