Optimization FlowShop Problem- Error Received

I have the following code for a flow shop problem.

In the following part

[optimalSequence, minMaxTardiness] = fmincon(objectiveFunction, initialSequence, A, b, Aeq, beq, lb, ub, [], options);

I get the following error. But the lb is basically a matrix on 1x20 with "1" and ub is the same with "20".

These are also reflected in the matlab data. Thanks for the help.

ERROR

Initial point X0 is not between bounds LB and UB;

FMINCON shifted X0 to strictly satisfy the bounds.

Unrecognized function or variable 'numJobs'.

Error in codev2>calculateMaxTardinessWithSequence (line 43)

completionTimes = zeros(numMachines, numJobs);

Error in codev2>@(sequence)calculateMaxTardinessWithSequence(sequence,processingTimes,dueTimes,sequenceDependentSetupTimes,numMachines) (line 17)

objectiveFunction = @(sequence) calculateMaxTardinessWithSequence(sequence, processingTimes, dueTimes, sequenceDependentSetupTimes, numMachines);

Error in fmincon (line 563)

initVals.f = feval(funfcn{3},X,varargin{:});

Caused by:

Failure in initial objective function evaluation. FMINCON cannot continue.

CODE

++

clc; clear all; close all;

% Number of machines and jobs

numMachines = 5;

numJobs = 20;

% Generate random processing times for jobs on machines

processingTimes = randi([1, 10], numMachines, numJobs);

% Generate random due times for each job

dueTimes = randi([20, 30], 1, numJobs);

% Generate random sequence-dependent setup times between products

sequenceDependentSetupTimes = randi([1, 5], numJobs-1, 1);

% Objective function for fmincon

objectiveFunction = @(sequence) calculateMaxTardinessWithSequence(sequence, processingTimes, dueTimes, sequenceDependentSetupTimes, numMachines);

% Initial guess (random permutation of jobs)

initialSequence = randperm(numJobs);

% Bounds for the decision variables (permutations of jobs)

lb(1: numJobs) = 1;

ub(1: numJobs) = numJobs;

% Constraints (none in this case)

A = [];

b = [];

Aeq = [];

beq = [];

% Use fmincon to minimize the objective function

options = optimoptions('fmincon', 'Display', 'iter', 'MaxIterations', 1000);

[optimalSequence, minMaxTardiness] = fmincon(objectiveFunction, initialSequence, A, b, Aeq, beq, lb, ub, [], options);

% Display the results

disp(['Optimal Sequence: ', num2str(optimalSequence)]);

disp(['Minimum Max Tardiness: ', num2str(minMaxTardiness)]);

% Function to calculate max tardiness with given sequence

function maxTardiness = calculateMaxTardinessWithSequence(sequence, processingTimes, dueTimes, setupTimes, numMachines)

completionTimes = zeros(numMachines, numJobs);

lostTimeDueToSetups = 0;

% Calculate completion times for each job on each machine based on the given sequence

for j = 1:numJobs

for i = 1:numMachines

currentJob = sequence(j);

if j == 1

if i == 1

completionTimes(i, currentJob) = processingTimes(i, currentJob);

else

completionTimes(i, currentJob) = completionTimes(i - 1, currentJob) + processingTimes(i, currentJob) + setupTimes(currentJob - 1);

lostTimeDueToSetups = lostTimeDueToSetups + setupTimes(currentJob - 1);

end

else

if i == 1

completionTimes(i, currentJob) = completionTimes(i, sequence(j - 1)) + processingTimes(i, currentJob);

else

completionTimes(i, currentJob) = max(completionTimes(i, sequence(j - 1)), completionTimes(i - 1, currentJob)) + processingTimes(i, currentJob);

end

end

end

end

% Calculate tardiness for each job

tardiness = zeros(1, numJobs);

for j = 1:numJobs

tardiness(j) = max(0, completionTimes(numMachines, j) - dueTimes(j));

end

% Calculate maximum tardiness

maxTardiness = max(tardiness);

++

Answer 1

[Alan Weiss]

You don't pass numJobs into your calculateMaxTardinessWithSequence function:

function maxTardiness = calculateMaxTardinessWithSequence(sequence, processingTimes, dueTimes, setupTimes, numMachines)

Alan Weiss

MATLAB mathematical toolbox documentation

[Fatih]

Thanks, it is my mistake. I also had another file with the same name and I was amending it. Now it works. thanks.