Estimation of variables from the inequality and equality constraints

2 Ansichten (letzte 30 Tage)
Muhammad Saeed
Muhammad Saeed am 7 Okt. 2022
Bearbeitet: Torsten am 10 Okt. 2022
Dear all,
I am facing a problem in the estimation of variables from the multivariable mathematical equations. The variables (t,tf,w1,w2) that I am trying to minimize are exist in both the equality and inequality constraints. In the following equations q1 and q2 are any numeric values and "t" is a continuous varaiable.
minimize tf,w1,w2
subjected to:
% tf≥0
% 0≤t≤tf
%-((w1/(2*tf))*(tf-t(i))^2)+(w2/(2*tf))*(t(i))^2+ (q2/tf - tf*w2/6)- (q1/tf - tf*w1/6)≤370
%[(w1/h)*(tf-t)+(w2/h)*(t)]≤140;
%(w2-w1/tf)≤300;
%-((w1*tf)/2)+(q2-q1)/tf+((w1-w2)*tf/6)=0;
%((w2*tf)/2)+(q2-q1)/tf+((w1-w2)*tf/6)=0;
I have already tried to solve the problem through fmincon in Matlab but unable to get a feasible solution.
options = optimoptions(@fmincon, 'MaxIterations',15000000, 'MaxFunctionEvaluations',30000, 'StepTolerance', 0.0000001);
[x] = fmincon(objective,tf,A,b,Aeq,beq,lb,ub,nonlincon,options)
I am very thankful if somebody can guide me to estimate the values of the variables in the objective function.
  3 Kommentare
Muhammad Saeed
Muhammad Saeed am 10 Okt. 2022
Thanks for the response.All of the variables at the same time.Because w1 is also dependent on tf.So all the varaibales should be considered at the same time while performing the minimization.
Torsten
Torsten am 10 Okt. 2022
Bearbeitet: Torsten am 10 Okt. 2022
So all the varaibales should be considered at the same time while performing the minimization.
Not possible - only if you use gamultiobj to find a pareto optimum.

Melden Sie sich an, um zu kommentieren.

Antworten (1)

Matt J
Matt J am 7 Okt. 2022
Since there are only 3 variables, you can do a discrete sweep of the bounded box described by lb, ub to find points that satisfy the constraints. If you find none, you might have to conclude that there are no solutions to be found.
If you find one, you can use the one with the smallest objective() value as your initial guess to fmincon.
  2 Kommentare
Muhammad Saeed
Muhammad Saeed am 8 Okt. 2022
Dear Matt,
thanks for the response and providing attention to the problem.
Indeed there are four variables because "t" is a continuous variable. Discrete sweep of the bounded box is suitable for all the variables or it can be useful to predict the values for the only one varaible?

Melden Sie sich an, um zu kommentieren.

Kategorien

Mehr zu Nonlinear Optimization finden Sie in Help Center und File Exchange

Community Treasure Hunt

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

Start Hunting!

Translated by