Help with plotting data in a mat file

Hi, I have series of data that I need to plot, however, the sum is not working properly, the values are not correct. Attached is my code.

for i=1:1:30
   F = "Fuel";
   E = "Emissions";
   P = "Power";
   R = "RPM";
   CO = "CO_2";
   SO = "SOx";
   NO = "NOx";
   Q = int2str(i);
   if i ==27 || i == 1 || i == 2 || i ==3
   else
     %% Fuel consumption
     A(i) = load(append(F,Q)); % Load Fuel Data
     B(i)= sum(A(i).Fuel(2,:)); % Sum Daily Fuel Data
     G(i) = B(i)/24; % Daily Fuel / Hr
     C = sum(B); % Total fuel Consumption in a month
     D = C/26;  % Average Fuel Consumption in a month
     Z = sum(G)/26; % Daily Average Fuel / Hr
     
     %% Emissions
     A1(i) = load(append(E,Q)); % Load Emission Data
     B1(i)= sum(A1(i).Emissions(2,:)); % Sum Daily Fuel Data
     G1(i) = B1(i)/24; % Daily Emission / Hr     
     C1 = sum(B1); % Total Emission in a month 
     D1 = C1/26;  % Average Emission in a month
     Z1 = sum(G1)/26; % Daily Emission / Hr
      
     %% Power 
     A2(i) = load(append(P,Q)); % Load Power Data
     B2(i)= 2*0.25*sum(A2(i).Power(2,:)); % Sum Daily Fuel Data
     G2(i) = B2(i)/24; % Daily Average / Hr
     C2 = sum(B2); % Total Power in a month
     D2 = C2/26;  % Average Power in a month
     Z2 = sum(G2)/26; %Daily Power / Hr
      
     %% RPM
     A3(i) = load(append(R,Q)); % Load Rpm Data
     B3(i)= sum(A3(i).RPM(2,:)); % Sum Daily rpm Data
     C3 = sum(B3); % Total rpm Data in a mont
     D3 = C3/26;  % Average rpm in a month
     
     %%  NOX EMISSION
     A4(i) = load(append(NO,Q)); % Load Fuel Data
     B4(i)= sum(A4(i).NOx(2,:)); % Sum Daily Fuel Data
     G4(i) = B4(i)/24; % Daily Fuel / Hr
     C4 = sum(B4); % Total fuel Consumption in a month
     D4 = C4/26;  % Average Fuel Consumption in a month
     Z4 = sum(G4)/26; % Daily Average Fuel / Hr
%      
     %% SOX EMISSION
     A5(i) = load(append(SO,Q)); % Load Fuel Data
     B5(i)= sum(A5(i).SOx(2,:)); % Sum Daily Fuel Data
     G5(i) = B5(i)/24; % Daily Fuel / Hr
     C5 = sum(B5); % Total fuel Consumption in a month
     D5 = C5/26;  % Average Fuel Consumption in a month
     Z5 = sum(G5)/26; % Daily Average Fuel / Hr
%      
     %% CO2 EMISSION
     A6(i) = load(append(CO,Q)); % Load Fuel Data
     B6(i)= sum(A6(i).CO2(2,:)) % Sum Daily Fuel Data
     G6(i) = B6(i)/24; % Daily Fuel / Hr
     C6 = sum(B6); % Total fuel Consumption in a month
     D6 = C6/26;  % Average Fuel Consumption in a month
     Z6 = sum(G6)/26; % Daily Average Fuel / Hr
    end
    
end
figure(1)
subplot(2,3,1)
    yline(D,'r')
    hold on
    bar(B,'b')
    xlabel ('Days of the Month');
    ylabel ('Fuel Consumption (Kg)')
    title('Daily Fuel consumption of marine diesel engine')
    legend('Average Fuel','Daily Fuel')
    grid on

subplot(2,3,2)
    yline(D1,'r')
    hold on
    bar(B1,'b')
    xlabel ('Days of the Month');
    ylabel ('Emissions (Kg)')
    title('Daily Emission of marine diesel engine')
    legend('Average Emission','Daily Emission')
    grid on

subplot(2,3,3)
    yline(D2,'r')
    hold on
    bar(B2,'b')
    xlabel ('Days of the Month');
    ylabel ('Power (KWh)')
    title('Daily Average load of marine diesel engine')
    legend('Average load','Daily Power')
    grid on
    
    t = annotation('textbox', [0.44, 0.40, 0.1, 0.1], 'String', "SIMULATION SUMMARY");
    t.FontSize = 16;
    t.FontWeight ='bold';
    t.LineWidth = 2;
    t.Color = 'r';
    t.EdgeColor = 'r';
    
    annotation('textbox', [0.15, 0.30, 0.1, 0.1], 'String', "Total Fuel Consumption =  " + C + " Kg ")
    annotation('textbox', [0.15, 0.20, 0.1, 0.1], 'String', "Average Fuel Consumption = " + D + " Kg ")
    
    annotation('textbox', [0.45, 0.30, 0.1, 0.1], 'String', "Total NOX Emission =  " + C4 + " Kg ")
    annotation('textbox', [0.45, 0.25, 0.1, 0.1], 'String', "Total SOX  Emission =  " + C5 + " Kg ")
    annotation('textbox', [0.45, 0.20, 0.1, 0.1], 'String', "Total CO_2  Emission =  " + C6 + " Kg ")
    annotation('textbox', [0.45, 0.15, 0.1, 0.1], 'String', "Total Emission =  " + C1 + " Kg ")
    annotation('textbox', [0.45, 0.10, 0.1, 0.1], 'String', "Average Emission =  " + D1 + " Kg ")
    
    annotation('textbox', [0.73, 0.30, 0.1, 0.1], 'String', "Daily Average Power = " + sum(G2)+" Kwh")

[Cris LaPierre]

A quick check appears to show that it is calculating a sum. Which sums are incorrect? What should the correct values be?

[chizom wornu]

For, instance I manually calculated the sum for the first file, the value obtained is different when I run the script.

This line of code is where the sum does not work

B(i)= sum(A(i).Fuel(2,:)); % Sum Daily Fuel Data

Answer 1

[Scott MacKenzie]

I think the error might be in how you are verifying your script. I ran your script and generated the plots. Here is what I see in the command window for the expression in the line of code you provided:

>> sum(A(i).Fuel(2,:))
ans =
       1196.7

That is the correct value, but it is for the last day in the month. Did you mistakenly think it was for the 1st bar?

Consider this by comparison:

>> sum(A(4).Fuel(2,:))
ans =
       833.71
       

This value is also correct, but it is for the 4th day of the month, which corresponds to the first non-zero bar in the chart:

Your script is fine, as best I can tell.

BTW, you should probably move the string assignments and the C, D, and Z calculations outside the for-loop. They only need to execute once.

[Cris LaPierre]

You need to be aware of what is happinging inside your loop (data for a single day) vs what is happening after the for loop finishes (data for the entire month).

for i=[4:26 28:30]
   F = "Fuel";
   Q = int2str(i);
   A(i) = load(append(F,Q)); % Load Fuel Data
   B(i)= sum(A(i).Fuel(2,:)); % Sum Daily Fuel Data
   G(i) = B(i)/24; % Daily Fuel / Hr
end
B

B = 1×30

1.0e+03 * 0 0 0 0.8337 1.2232 1.8735 1.5742 1.5302 1.3855 1.5622 1.5687 1.4690 1.4644 1.1596 1.3225 1.8735 0.7340 1.2916 0.9036 1.4509 1.6663 1.5512 1.5002 1.6155 0.7468 0.4044 0 0.8731 1.2989 1.1967

C = sum(B) % Total fuel Consumption in a month

C = 3.4073e+04

D = C/26  % Average Fuel Consumption in a month

D = 1.3105e+03

Z = sum(G)/26 % Daily Average Fuel / Hr

Z = 54.6049

[chizom wornu]

Thank you all, the code was actually right. I didnt change the folder so it was ploting different data from what i want it to plot.