4 ms·

Compared to.. protein folding, nuclear fusion? Sounds like a handful of parameters to me. What are computers good for if not looking for solutions in this space

Compared to.. protein folding, nuclear fusion? Sounds like a handful of parameters to me. What are computers good for if not looking for solutions in this space? It's strange to me that the cargo space has not been aggressively optimized. It's a pretty substantial part of civilization and, I believe, there's definitely some money sloshing around there.

hermitcrab 2y ago
A Panamax can carry ~5000 containers. 5000! (5000 factorial) is a BIG number. Bear in mind that 60! is more than the number of atoms in the observable universe. Combinatorial problems are hard.
- pineaux 2y ago
  This is if you are looking in an naive way and are only interested in for THE BEST solution. However, there are many constraints and we are looking for a better solution not the best one.
  - smarm52 2y ago
    Yes exactly, I'm reminded of solutions to find numerical approximation results for very difficult problems like this. One of the most famous are Markov chain approaches to resolving similar issues. Then, for the interested: https://en.wikipedia.org/wiki/Markov_chain https://en.wikipedia.org/wiki/Markov_chain
- huygens6363 2y ago
  For some reason, ignorance most likely, I'm not impressed. Looks relatively easy. Not for me, but for anybody with some math skills it looks easy to improve upon naive solutions. To be fair, a completely optimal solution definitely seems out of reach, but I'm not interested in those.
  - saagarjha 2y ago
    The constraints are not always easily evident, unfortunately.
  - namibj 2y ago
    The issue is in adequately capturing and encoding these constraints; particularly multi-crane piers that skip an intermediate autonomous shuttle truck to go directly onto trains are quite difficult. Just imagine the contingency planning due to restrictions in unloading.
  - mcguire 2y ago
    Hmm. Let's say you're looking at that 5000 TEU (Twenty-foot Equivalent Units) ship with (the most common, IIUC) 40' containers. The state space for optimization has something like 2500! or 10^7400 states. Given 24 hours to optimize it at 1ns per state, you could look at 10^14 states or 10^-7384% of the state space. There are also a lot more constraints than weight and balance and they're constantly changing; some may rule out big chunks of the state space which is very good, but it's still a Hard Problem. But it's not like there aren't people already doing it. https://www.herbert-abs.com/cargomax-for-container-ships https://www.herbert-abs.com/cargomax-for-container-ships https://www.lineroptimizer.com/ https://www.lineroptimizer.com/
  - hermitcrab 2y ago
    Everything is easy to the person that doesn't have to do it.
- smarm52 2y ago
  Then for others, they're referring to these class of problems: https://en.wikipedia.org/wiki/Combinatorial_optimization https://en.wikipedia.org/wiki/Combinatorial_optimization

hermitcrab 2y ago

A Panamax can carry ~5000 containers. 5000! (5000 factorial) is a BIG number. Bear in mind that 60! is more than the number of atoms in the observable universe. Combinatorial problems are hard.

pineaux 2y ago
This is if you are looking in an naive way and are only interested in for THE BEST solution. However, there are many constraints and we are looking for a better solution not the best one.
- smarm52 2y ago
  Yes exactly, I'm reminded of solutions to find numerical approximation results for very difficult problems like this. One of the most famous are Markov chain approaches to resolving similar issues. Then, for the interested: https://en.wikipedia.org/wiki/Markov_chain https://en.wikipedia.org/wiki/Markov_chain
huygens6363 2y ago
For some reason, ignorance most likely, I'm not impressed. Looks relatively easy. Not for me, but for anybody with some math skills it looks easy to improve upon naive solutions. To be fair, a completely optimal solution definitely seems out of reach, but I'm not interested in those.
- saagarjha 2y ago
  The constraints are not always easily evident, unfortunately.
- namibj 2y ago
  The issue is in adequately capturing and encoding these constraints; particularly multi-crane piers that skip an intermediate autonomous shuttle truck to go directly onto trains are quite difficult. Just imagine the contingency planning due to restrictions in unloading.
- mcguire 2y ago
  Hmm. Let's say you're looking at that 5000 TEU (Twenty-foot Equivalent Units) ship with (the most common, IIUC) 40' containers. The state space for optimization has something like 2500! or 10^7400 states. Given 24 hours to optimize it at 1ns per state, you could look at 10^14 states or 10^-7384% of the state space. There are also a lot more constraints than weight and balance and they're constantly changing; some may rule out big chunks of the state space which is very good, but it's still a Hard Problem. But it's not like there aren't people already doing it. https://www.herbert-abs.com/cargomax-for-container-ships https://www.herbert-abs.com/cargomax-for-container-ships https://www.lineroptimizer.com/ https://www.lineroptimizer.com/
- hermitcrab 2y ago
  Everything is easy to the person that doesn't have to do it.
smarm52 2y ago
Then for others, they're referring to these class of problems: https://en.wikipedia.org/wiki/Combinatorial_optimization https://en.wikipedia.org/wiki/Combinatorial_optimization