I am trying to solve maximum coverage location problem (MCLP) using LINGO 15.0, Optimization software. Everything seems to be working fine except the Objective function which does not change with change of any constrains. Need help with the code itself. I run the code with several different constraints but the final output does not change at all. What could be the problem?
Hi~ You can send your mathematical model and Lingo programming to my email: [email protected]~ I will try to see if i can do some help with the lingo programming :)
If you have a MCLP there are weights to be covered (demands) and a fixed amount of resources with which you wish achieve maximum coverage. If you provided a very large amount of resources you could cover everyone (right?) and if you increased the resouces the coverage could not improve -- so it is possible that you have some kind of mistake about the amount of available resources. On the other hand a simple sign or inequality reversal on a key constraint could make the problem give incorrect answers. Is your question about the formulation or the translation of that formulation into LINGO? You may also need to be careful to enforce integer variables
I am providing equal weights to all the demand points but using constraints to weigh and select the best candidate points. In addition I have limit on the resources that could be used in the form of number of warehouses that could be opened. But the problem here is that the objective function does not seem to abide the constraints. and it a binary problem, no partial coverage is considered.
I translated the formulation to lingo and the program runs just fine except the objective function.
Send us your formulation. It is hard to know what it means to say "the program runs just fine except the objective function." That seems to mean that it does not run fine, or there is a coding error in the objective function. Send an example or code instance if you still need assistance.
Thank you Morton, now the code is working, got help from Hao.
Thanks again.
It might be good for the general reader to avoid whatever mistake to hear what the issue was? you can send it privately if it a small bug (mail: [email protected])
You may consult the book on LINGO operating system LINGO 14 version downloading it from internet with free of charge. Thanks.
Hi, Rajali Maharjan ,I think I have met the same question with you. Can you send your mathematical model and Lingo programming to my email: [email protected] I can find out the problem consulting yours. Thanks!
I also need help on Lingo programming. I have a mixed integer programming to solve it using sets in Lingo. One of the constraints is :
S(i,k,w)>=m(i,j)*X(i,t) , for i=1,...,I ; j=1,...,J; t=1,..,T;
k=t+K(j,w)-1,..,t+K(j,w)+S(j)-2 ; w=1,..,W.
Here m(i,j), K(j,w) and S(j) are parameters.
The problem is i do not know how to enter index k using sets in Lingo.
Any help would be highly appreciated.
Sorry for such delayed reply.
Using sets is a way to define parameters which you will use in the later parts of your objective function or constraints. If k is a parameter of demand or supply then include it within that set.
Eg:
SET
demand /1..N/: k;
ENDSET
I hope it helps.
I am very surprised many researcher did not know the simple and important information of LINDO products.
1. Demo version, manuals and Linus textbooks are free. If English speakers read those book, you can understand the Set expression and others. If you can understand Japanese, see my announcement of DEA, Cancer Gene Diagnosis, several translations and original two books.
2. Linus reviewed many papers and books. He made over 500 sample models. I need not survey the papers and develop new approach about DEA model by modification of sample DEA.
3. Linus explains many sample models. Data are defined in Data section. But, you define those data on Excel. You can read it by @OLE function and output Excel. If you must a big data, you choose the DB.
4. I developed “100-fold cross validation for small sample method and Matryoshka Feature Selection method for microarray datasets.” See the Chap.2 and Chap.9 of my Springer book (2016).
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Hi, Rajali Maharjan , I have met the same question with you regard to location selection . Can you send your mathematical model and Lingo programming to my email: [email protected]!
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