RightChain Routing Transcript

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Never. It's that difficult. Normally [00:15:00] what you have to have are some good, what are called heuristics. We're really nerding out now let's do some examples of heuristics here for just a little bit and you're going to get to try your hand at this today too. Let's suppose there's a distribution center here and these are the customers I've got to visit. I'm going to create a route. I want you to tell me if I'm doing a good job or a bad job. I do. [00:15:30] It was amazing. It was so good. It was amazing. Now, where did I go wrong? We started here. We went up here, we came down here, went over here, down here, back here, and stopped right there. Now, at some point along the way, you just went nuts. There was something I did that you really got upset about. What was that? Dr. Frazelle (15:53): Backtrack. In the absence of time constraints, a good route never crosses itself. [00:16:00] That's rule number one. We're going to build some rules for routing. These will be routing rules in the absence of time constraints, time, windows a good route never crosses itself. What else wrong with that picture? [00:16:30] We didn't visit all the locations, so that's going to be another one. We must visit all locations. What else is wrong? There's something really bad wrong. We didn't get back home finishes at the home location. [00:17:00] Let's try a few more. There's some simple rules you can use to help build good routes. Is that a good route? Relatively speaking, never crossed itself. We visited all the customers. What's missing? The dc This little algorithm is called Route first, [00:17:30] cluster second. Dr. Frazelle (17:36): Oftentimes what the software is doing is it creates a route between all the customers. Then based on the capacity of the vehicle because we hadn't even gotten into that yet, and the requirements of the truck, it'll create routes and then efficient routes and then it will try to interchange the start and stop points [00:18:00] and that's why you're watching the algorithm. You see the routes getting better and better and better and better, and if you let it run forever, which of course you can't do, eventually you get to the optimal solution, but you can't let it run for infinite time. That's why it's in this class of problems that is so difficult, but if you get a good route and it meets all these requirements, you're actually in pretty good shape. Now let's try this with some capacities. Here's the distribution center and let's say that our vehicle [00:18:30] can carry eight pallets at a time and they want four and they want five and they want one and they want two and they want six and they want three. They want 4, 1, 5, 8, 7, and two. Dr. Frazelle (18:48): Pure delivery, no pickups. The cluster first would say, let's find nodes that are close together [00:19:00] that are pretty close to this requirement right here. So somebody tell me where those might be. The first thing you look for is one all by itself. That's eight. That's a cluster all into itself, so I'm out and back. Where's another pair of two or three physically close together that make eight to six and two? [00:19:30] Here's two fours here and back. Is that a good set of routes? Did it meet the constraints? Yeah, we visited every customer with the required quantity. Now, could it be better? How would you figure out if it could be better?

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