MATLAB Answers

For loop preallocation warning?

13 views (last 30 days)
Tony Castillo
Tony Castillo on 15 Oct 2020
Commented: Ameer Hamza on 16 Oct 2020
Hello all,
Even the code works properly, I get a warning flag that advice me to preallocate all of the variables that I am accumulating during the execution of the code, do you know how to deal with this issue?, in order to debug and make faster the execution of the code.
Thanks in advance!.
%To simulate the 12 months at one click
current_path = pwd;
tic
load DATA_HILL.mat
PV_MAX_=[];
DEV_PV_=[];
SOC_=[];
month_=[];
PV_irr_=[];
Dev_2_=[];
z=zeros(12,6);
for month_number=1:12
sim('HILL_V2.slx')
disp(month_number);
bdclose('HILL_V2.slx');
%%%%%%
%%%%Data upload
load Power_PV.mat
load SOC.mat
load month
load Irr
%%%Results format
format Eng
%%%%Variables analysed in this study case
PV_MAX=max(Power_PV);
%
DEV_PV= (PV_MAX/189000)*100;
%
SOC= min(SOC);
m=mean(month);
PV_irr=max(Irr)*189;
Dev_2=(1-(PV_MAX/PV_irr))*100;
% % % % All of the accumulated variables in the for loop
PV_MAX_=[PV_MAX; PV_MAX_];
DEV_PV_=[DEV_PV; DEV_PV_];
SOC_=[SOC; SOC_];
month_=[m; month_];
PV_irr_=[PV_irr; PV_irr_];
Dev_2_=[Dev_2; Dev_2_];
cd(current_path);
end
A=flip([month_ SOC_ PV_MAX_ DEV_PV_ PV_irr_ Dev_2_].*z);
%%%%To creat a table in order to represent the results of the simulation
% RowName={'Month', 'SOC_min(%)', 'PV_MAX (kW)', 'DEV_PV (%)', 'PV_irr (kW)', 'Dev_2 (%)'};
LastName=flip({'Jan';'Feb';'Mar';'Apr';'May';'Jun';'Jul';'Aug';'Sep';'Oct';'Nov';'Dec'});
T=table(month_, SOC_, PV_MAX_, DEV_PV_, PV_irr_, Dev_2_,...
'RowName', LastName);
disp(T)
toc
  2 Comments
Tony Castillo
Tony Castillo on 15 Oct 2020
In and overall view it results some confusing to me, maybe because I implemented and the warning is still on.

Sign in to comment.

Accepted Answer

Ameer Hamza
Ameer Hamza on 15 Oct 2020
Edited: Ameer Hamza on 15 Oct 2020
Here is a general way.
If you use the following codes, you will get a warnings
x = []
for i = 1:10
x(i) = sin(i); % sin(i) used as example
end
% or
x = []
for i = 1:10
x = [x sin(i)]
end
You can solve the warning by pre-allocating and use indexing to assign elements
x = zeros(1, 10)
for i = 1:10
x(i) = sin(i); % sin(i) used as example
end
For your code, following will work
%To simulate the 12 months at one click
current_path = pwd;
tic
load DATA_HILL.mat
PV_MAX_=zeros(12,1);
DEV_PV_=zeros(12,1);
SOC_=zeros(12,1);
month_=zeros(12,1);
PV_irr_=zeros(12,1);
Dev_2_=zeros(12,1);
z=zeros(12,6);
for month_number=1:12
sim('HILL_V2.slx')
disp(month_number);
bdclose('HILL_V2.slx');
%%%%%%
%%%%Data upload
load Power_PV.mat
load SOC.mat
load month
load Irr
%%%Results format
format Eng
%%%%Variables analysed in this study case
PV_MAX=max(Power_PV);
%
DEV_PV= (PV_MAX/189000)*100;
%
SOC= min(SOC);
m=mean(month);
PV_irr=max(Irr)*189;
Dev_2=(1-(PV_MAX/PV_irr))*100;
% % % % All of the accumulated variables in the for loop
PV_MAX_(i)=PV_MAX
DEV_PV_(i)=DEV_PV;
SOC_(i)=SOC;
month_(i)=m;
PV_irr_(i)=PV_irr;
Dev_2_(i)=Dev_2;
cd(current_path);
end
A=flip([month_ SOC_ PV_MAX_ DEV_PV_ PV_irr_ Dev_2_].*z);
%%%%To creat a table in order to represent the results of the simulation
% RowName={'Month', 'SOC_min(%)', 'PV_MAX (kW)', 'DEV_PV (%)', 'PV_irr (kW)', 'Dev_2 (%)'};
LastName=flip({'Jan';'Feb';'Mar';'Apr';'May';'Jun';'Jul';'Aug';'Sep';'Oct';'Nov';'Dec'});
T=table(month_, SOC_, PV_MAX_, DEV_PV_, PV_irr_, Dev_2_,...
'RowName', LastName);
disp(T)
toc
  4 Comments
Ameer Hamza
Ameer Hamza on 16 Oct 2020
I am glad to be of help!

Sign in to comment.

More Answers (0)

Products


Release

R2019b

Community Treasure Hunt

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

Start Hunting!