Multiply array if number is under certain value

4 views (last 30 days)
Im using a script to calculate power from two varaiables. Though i need to multiply my power (P_out) with a certain value (for example 2) if the value is under 1.000.000 to correct my data...
So i have 144 numbers, and all numbers beneath 1.000.000 needs to be multiplied by 2. Maybe 30 of these values are beneath 1.000.000...
How do i do this? Hope someone knows this
This is the code:
Data = readtable('Rejstrup Pyra .xlsx'); %Celcius
T_Pyra = table2array(Data(83:(223),8))
Radiation = table2array(Data(83:(223),3)) %kW/m^2
PV_radiation = Radiation./1000
T_modul = (T_Pyra)+(PV_radiation/20) %Celcius
T_korrektion = 1-(T_modul-T_Pyra).*(0.40/100)
I_korrektion = 0.988
P_peak = 23947000 %watt
P_out = P_peak.*T_korrektion.*I_korrektion.*PV_radiation %Watt
This is my values for my power, where every value beneath 1.000.000 needs to be multiplied with 2.
Exporting it to excel (not relevant):
filnavn='Beregnet P_available fra Rejstrup.xlsx'
Best regards

Answers (1)

Mathieu NOE
Mathieu NOE on 22 Mar 2022
this is very simple - see below :
P_out = 1000000 + 80000*randn(10,1); % dummy data
hold on
ind = P_out<=1000000; % find values below 1000000
P_out(ind) = P_out(ind)*2; % correction (put the right correction factor here)
hold off
Mathieu NOE
Mathieu NOE on 22 Mar 2022
I put back those lines in the code (see below) , but I have a hard time to see what the 0.97 makes as an improvement ?? or did I forgot another piece of code from the past ?
this is not doing any shift in the early hours...
see figure 1 (below)
figure 2 is simply the "heavy" correction method I already posted above
%% reference data (grey)
Data_ref = readtable('Rejstrup Effekt.xlsx','VariableNamingRule' ,'preserve'); %Celcius
% [m,n] = size(Data_ref);
ind_start = 60; %
ind_stop = 222; %
Data_ref = Data_ref(ind_start:ind_stop,:); % retrict all table data between two time indexes from 7:10 AM to 18:25 PM
Data_ref_time = datetime(table2array(Data_ref(:,1)));
P_out_ref= table2array(Data_ref(:,2));
%% measurement (blue, to be corrected)
Data = readtable('Rejstrup Pyra .xlsx','VariableNamingRule' ,'preserve'); %Celcius
% [m,n] = size(Data);
Data = Data(ind_start:ind_stop,:); % retrict all table data between two time indexes from 7:10 AM to 18:25 PM
Data_time = datetime(table2array(Data(:,1)));
T_Pyra = table2array(Data(:,8));
Radiation = table2array(Data(:,3)); %kW/m^2
PV_radiation = Radiation./1000;
T_modul = (T_Pyra)+(PV_radiation/20); %Celcius
T_korrektion = 1-(T_modul-T_Pyra).*(0.40/100);
I_korrektion = 0.988;
P_peak = 23947000; %watt
P_out = P_peak.*T_korrektion.*I_korrektion.*PV_radiation; %Watt
%% basic correction
P_out_corrected = P_out; % init P_out_corrected
ind = 116 - ind_start; % find time line corresponding 9:30 AM
P_out_corrected(1:ind) = P_out_corrected(1:ind)*0.97; % correction # 1 (put the right correction factor here)
legend('ref (grey)','blue (uncorrected)','blue (corrected)');
%% full correction (remove code below if necessary)
% make the blue match exactly the grey
P_out_corrected = P_out; % init P_out_corrected
ind = P_out<eps;
P_out_ref(ind) = 0; % avoid very high (inf) cor_factor due to division by eps !
cor_factor = P_out_ref./(P_out+eps); % + eps to avoid division by zero if P_out = 0 !
P_out_corrected = P_out_corrected.*cor_factor;
legend('ref (grey)','blue (uncorrected)','blue (corrected)');

Sign in to comment.


Find more on Data Distribution Plots in Help Center and File Exchange




Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!