Difference between implementation and description of problem RE4-6-2
salomonl opened this issue · comments
Hey @ryojitanabe. Thank you for having coded the examples in different languages, it helped me a lot to debug my code which uses these examples.
There is a difference between the description of constraint g7 = 500000 - DWT
in the supplementary material pdf and the way it is implemented for example in the c
version or the python
version. In this case, the constraint is g7 = 50000.0 -DWT
. I took a look in the original implementation described in the original paper
Parsons, M. G., & Scott, R. L. (2004). Formulation of Multicriterion Design optimization Problems For Solution With Scalar Numerical Optimization Methods. Journal of Ship Research, 48(1), 61-76.
which corresponds to g7 = 500000 - DWT
. Is there a reason for which you removed a 0 ?
Maybe another error of typo in the same problem. When I look at the equation S-100
, I understand it as the fact that the annual_cargo
variable is negative as annual_cargo = - CARGO_DWT * RTPA
. Consequently, one user, when looking at the problem can think (it was my case) that f1 = annual_cost / annual_cargo
is negative, which is not the case, as it is clarified by your implementation. The simplest will be to make the following correction: f3 = - annual_cargo = - CARGO_DWT * RTPA
or -f3 = annual_cargo = cargo_dwt * RTPA
.
Thank you again for having collected in the litterature this great set of real benchmarks !
Thank you for pointing out the bug and the typo. I have fixed them.