Merchant Agents

[boomer70]

Tried to post to the old thread but it didn't work.

Anyway I am looking at implementing merchants actually transporting the goods they are trading. I have a few questions that I didn't find answers to in any of the documentation.
1. Do we want a single route to allow multiple forms of transport to be used. That is, should we allow the algorithm to find a route something like take wagons to port city A then go by trireme to port city B then by porters to city C? If so is there any penalty for changing transport midstream?
2. Had anyone come up with cost numbers for any of the functionality? Like what is the startup cost of a route using a trireme? What is the cost per turn and/or per square of movement?
3. Do we assume that the deal is made independant of what it will cost to actually ship the goods or do we need a way of evaluating the route prior to accepting the deal?
Well those are a few of the questions that I had thought of to this point. I am sure I will have more as things progress.

[Mark_Everson]

Re: Merchant Agents

Hi boomer:

Thanks for getting this seriously going!

Originally posted by boomer70
1. Do we want a single route to allow multiple forms of transport to be used.

Yes.

If so is there any penalty for changing transport midstream?

Yes, but I think it needs to be a TBD amount.

2. Had anyone come up with cost numbers for any of the functionality? Like what is the startup cost of a route using a trireme? What is the cost per turn and/or per square of movement?

Nope, I think the best approach is to make these settable with xml, and let the scenario guys test out the numbers.

3. Do we assume that the deal is made independant of what it will cost to actually ship the goods or do we need a way of evaluating the route prior to accepting the deal?

Need to be able to evaulate before merchant commits to the route.

For the use of people looking into our more recent discussions, here is the old Merchant Agents thread.

[boomer70]

Here are some thoughts that I had after pondering the algorithm that will be required to implement merchant routes:
1. I had the thought that it might be easier/better? to implement trade routes at the Civ level. This would have several benifits in terms of performance:
a. Each merchant going to the same place would end up using the same path since I can't see any variables that would change for a merchant created by the same Civ.
b. This would mean we could afford to update routes more frequently since presumably there would be fewer routes.
c. New routes could test to see if an existing route will get them close to where they need to go and only forge a new route where one doesn't exist.
d. Scenario designers could add trade routes to a scenario, probably including waypoints.
e. Makes the problem of finding ports/airports much simpler.

2. In some documentation somewhere there was talk of some transports having a range and incuring foraging penalties if they go beyond this range. Should the range be automatically reset if the route passes through a city? This could optionally have a small penalty for resupply. This would probably cause routes to hop from city to city on the route to the destination which I think is reasonable.

3. I will need some method of picking a transport type. What parameters will need to go into this decision? Do they need to be configurable by scenario? by culture? player choice?

4. Do we want to allow the player the ability to create trade routes in much the same way they create roads? This would make protecting the routes much easier as you wouldn't have to worry about the route trapsing through your border territories.

Until next time.

[Mark_Everson]

Hey boomer:

Originally posted by boomer70
Here are some thoughts that I had after pondering the algorithm that will be required to implement merchant routes:
1. I had the thought that it might be easier/better? to implement trade routes at the Civ level. This would have several benifits in terms of performance: (snip)

Trade routes at the civ level only is too broad a simplification to be my first choice. But it is certainly something we could go to if nothing else works with acceptable resource usage. However, if its coded the way I spec out below, we could fairly simply change it to your approach if needed.

My current thoughts are that we should have two types of merchants. A city/city (or province/province) merchant would solely trade between cities, seriously constraining the search space. The second type would be A city/country merchant, which would solely deal with bringing goods from a city (or maybe just the provincial capital) out to nearby non-city squares. I was thinking of doing this in some aggregated way, essentially for the entire province a city or trading center of some sort would supply the rest of the non-city squares. Exact method TBD.

2. In some documentation somewhere there was talk of some transports having a range and incuring foraging penalties if they go beyond this range. Should the range be automatically reset if the route passes through a city? This could optionally have a small penalty for resupply. This would probably cause routes to hop from city to city on the route to the destination which I think is reasonable.

Sounds very reasonable to me. For the first go-around you can make the transport characteristics very simple and ignore range issues. We can always add them later. Don't want to work you too hard on details .

3. I will need some method of picking a transport type. What parameters will need to go into this decision? Do they need to be configurable by scenario? by culture? player choice?

Starting with a generic land (and another for water) transport type that depends on technology sounds like a good start. We might never need more. Since trade and trade routes aren't the focus of Clash we can easily cut some corners here IMO.

4. Do we want to allow the player the ability to create trade routes in much the same way they create roads? This would make protecting the routes much easier as you wouldn't have to worry about the route trapsing through your border territories.

This sounds ok to me. The heuristic that the merchant uses to determine the route should really have the factors you cite in it already. I would think they would prefer a safe route that goes outside your civ to an unsafe on that is within the civ. Perhaps we should just give the player a budget for trade route protection that is allocated based on traffic. What do you think?