Using different solvers in Optimization Problem

NN
2022 10 24
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更新时间：2022 11 8
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Hi,
I am using problem based optimization problem and i am getting same optimized values for ga, patternsearch and particle swarm .but time taken is different.
Please advice what could be the mistake

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Walter Roberson
Walter Roberson 2022-10-24

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If you are getting exactly the same results, then there are a few possibilities:
  • you might have a mistake in your equation implementation that causes it to return the same values all of the time;
  • you might have a mistake in how you specify the solver, causing it to always be set the same;
  • you might have specified options such as integer constraints that are leading Problem Based Solver to override your solver request because the other solvers cannot handle the options / request
If you are getting the same results to within round-off error but not bit-for-bit identical:
  • you might be using a simple linear equation or quadratic equation; all of the functions should converge for those kinds of function
  • the result you are getting might be right at one of the constraint boundaries, so all of the solvers might end up at much the same solution

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NN
NN 2022-10-24
% Minimise the cost of power
prob.ObjectiveSense = 'minimize';
prob.Objective =dt *Cost'*PESSV;
showproblem(prob)
options = optimoptions('ga',prob.optimoptions,'Display','iter');
%options = optimoptions('patternsearch',prob.optimoptions,'Display','iter');
%options = optimoptions('ga',prob.optimoptions,'Display','iter');
%options = optimoptions(aprticleswarm',prob.optimoptions,'Display','iter');
[values,~,exitflag] = solve(prob,'Options',options);
fval = evaluate(prob.Objective,values);
NN
NN 2022-10-24
Kindly review this code and plz let me know if there is a correction.
NN
NN 2022-10-24
I have specified my constraints as below:
% Satisfy power load with power from PV, grid and ESS
prob.Constraints.loadBalance = Ppv + windV+ PgridV + PESSV == Pload;
prob.Constraints.grid = PgridV <=3e6;
prob.Constraints.solar = Ppv <=1e6;
Walter Roberson
Walter Roberson 2022-10-24
Can you post your complete code for testing ?
NN
NN 2022-10-24
function [Pgrid,Pess,Eess] = battSolarOptimizetrial3(N,dt,Ppv,Pwind,Pload,Einit,Cost,FinalWeight,batteryMinMax)
% Minimize the cost of power from the grid
prob = optimproblem;
% Decision variables
PgridV = optimvar('PgridV',N);
PessV = optimvar('PesssV',N,'LowerBound',batteryMinMax.Pmin,'UpperBound',batteryMinMax.Pmax);
EessV = optimvar('EesssV',N,'LowerBound',batteryMinMax.Emin,'UpperBound',batteryMinMax.Emax);
% Maximise the profit from the usage of battery and PV
prob.ObjectiveSense = 'minimize';
prob.Objective =dt *Cost'*PessV;
% Satisfy power load with power from PV, grid and battery
prob.Constraints.loadBalance = Ppv + Pwind+ PgridV + PessV == Pload;
prob.Constraints.grid = PgridV <=3e6;
prob.Constraints.solar = Ppv <=1e6;
showproblem(prob)
options = optimoptions('ga',prob.optimoptions,'Display','iter');
[values,~,exitflag] = solve(prob,'Options',options);
fval = evaluate(prob.Objective,values);
tb1=struct2table(values)
% Parse optmization results
if exitflag <= 0
Pgrid = zeros(N,1);
Pess = zeros(N,1);
Eess = zeros(N,1);
else
Pgrid = values.PgridV;
Pess = values.PessV;
Eess = values.EessV;
end
NN
NN 2022-10-24
移动：Walter Roberson 2022-10-25
  • you might have a mistake in how you specify the solver, causing it to always be set the same;--- I just changed the solver name in the solve command below:
options = optimoptions('ga',prob.optimoptions,'Display','iter');
  • you might have specified options such as integer constraints that are leading Problem Based Solver to override your solver request because the other solvers cannot handle the options / request
How do i correct it without modifying the constraints?what is the possible solution ?
NN
NN 2022-10-25
Please let me know what it means by moving the comment
Walter Roberson
Walter Roberson 2022-10-25
You posted content as an Answer, but the content was not a solution to your question and was instead a reply to what I had posted. I used moderation facilities to move your content to be a Comment rather than an Answer
NN
NN 2022-10-25
Ok Now understood I was actually asking what is the solution Please let me know if there are any solution after reviewing the code.
Walter Roberson
Walter Roberson 2022-10-25
I haven't had time to test it yet.
NN
NN 2022-10-26
Ok, please check if you are free .
When i used patternsearch, i got a warning like below:
You have passed PATTERNSEARCH options to LINPROG. LINPROG will use the common options and ignore the PATTERNSEARCH options that do not apply.
To avoid this warning, convert the PATTERNSEARCH options using OPTIMOPTIONS.
NN
NN 2022-11-8
Hi,
Can you please chekc on the above problem and suggest a solution please

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