a stab at economies

[rust]

I did take a look at the spreadsheet, but I have to admit that I can not give
you any meaningful feedback - the complexity of the matter "beats me".

 

[Ishmael]

yeah, I figured it was a bit over the top...
I'll put notes on all the cells to explain what each is doing and what is 'enterable'. Hopefully I'll get that done by the end of the holiday weekend here.

 

[Peter Schutze]

>I haven't settled on a model for shipping costs, tho

isnt Canon a standard/flat 1000cr per jump ?

>Has anyone took a look at the sheet yet?

Briefly looked it over last night. Its definitely a good start but beyond that I havent looked hard.

One point to note though is that agriculture and resource extraction have gotten rapidly more capital intensive and labour lite as tech progresses and is likely to continue in the future.

Thus you probably want to incorporate a TL based modifier for both .... counteracted by the hostility of the environment up to a certain point. I doubt environment (except insidious/corrosive) matters much for resources by TL10 due to remote operation.

 

[Ishmael]

canon is standard flat rate per jump...which I find unsatisfactory.
faster travel should be more costly.
thats not just per jump, but moving to jump point too, I would think, although I might not get that crazy yet.
Higher jump numbers should cost more...

I suppose none of this really matters for pc trade except cost and prices, because a 200ton trader is nothing when talking of millions of dtons of freight.
Bulk freighters would be like unit trains slow and cheap and huge capacity.
larger traders would be like over-the-road semi's...faster, more costly per ton, more flexible.
pc level free traders would be like small vans or panel trucks...courier/small package service ( in comparison )

I'm not using capital or infrastructure in this model ( I have another but it gives me a headaches...at least until I start playing with python in earnest ), so they are abstract and not bothered with....labor is also abstracted in that every agriculture laborer is not a farmer, but rather some worker in the food and food distribution industry. Farmers, and bakers, and butchers, and packaging people. Even the truckers that transport the food. Industry and resource labor is the same. 'other' represents the service industry and anyone not in the other 3 or military.

Enviroment modifiers are only in place for agriculture...the further from atm=6 and hyd=6, the less is produced per laborer to simulate added capital/infrastructure costs. Tech level mods are handled by the exchange rate...each laborer produces 24,000Cr worth of goods in LOCAL rates. This will be a fraction of the value of goods for Imperial rates. I am using Imperial rates as a standard and all goods shipping through space ( Imperial territory ) will have their costs adjusted. I handwave that the Imperium forces this standard rate in order to keep someone from getting rich just by shipping money between worlds. Once the goods reach the destination world, it is converted from Crimps to that world's local currency. ( fun fun trying to find a reputable moneychanger who won't shaft touristas ).

so a unit of goods thats worth 24,000 on one world might be worth only 6,000 Crimps and once shipped to another planet, it might be sold for 14,000Cr(local) after that world's exchange rate is figured. PC's don't have to worry as anything in a starport will be listed in Crimps anyways...in the end..low tech is worth much much less than high tech.

lol...all this to get the stupid export chart at the end....
I"ll do docs this weekend for what I did and why.

 

[Darkhstarr]

Back in the late 80's I came up with the idea of a Traveller commodities page based off the commodities page in the Wall Street Journal. However that was a lot of work using a legal pad & typewriter so I abandoned it. Never got back to it even though now I have a word processor.
I also started a listing for planetary data for exports & imports for a few of my systems. Had the idea making part of the system data. Thought it not only might be helpful in creating trading adventure hooks but also provide places to dump loot a bargain prices. May eventually post the few I wrote up someday.

 

[redwalker]

yeah, I figured it was a bit over the top...
I'll put notes on all the cells to explain what each is doing and what is 'enterable'. Hopefully I'll get that done by the end of the holiday weekend here.

It's a joke on some BBSs that Traveller is the game for folks who are addicted to operations research.

Be that as it may, if anyone here *does* know operations research, you may have seen an application of the network flow problem to commodities.

Just to yank a little OR out of a PDF:

The minimum cost flow problem holds a central position among network optimization mod-
els, both because it encompasses such a broad class of applications and because it can be
solved extremely efficiently. Like the maximum flow problem, it considers flow through a
network with limited arc capacities. Like the shortest-path problem, it considers a cost (or
distance) for flow through an arc. Like the transportation problem or assignment problem of
Chap. 8, it can consider multiple sources (supply nodes) and multiple destinations (demand
nodes) for the flow, again with associated costs. In fact, all four of these previously studied
problems are special cases of the minimum cost flow problem,as we will demonstrate shortly.
The reason that the minimum cost flow problem can be solved so efficiently is that
it can be formulated as a linear programming problem so it can be solved by a stream-
lined version of the simplex method called the network simplex method. We describe this
algorithm in the next section.
The minimum cost flow problem is described below.
1. The network is a directedand connectednetwork.
2. At least oneof the nodes is a supply node.
3. At least oneof the other nodes is a demand node.
4. All the remaining nodes are transshipment nodes.
5. Flow through an arc is allowed only in the direction indicated by the arrowhead, where
the maximum amount of flow is given by the capacityof that arc. (If flow can occur in
both directions,this would be represented by a pair of arcs pointing in opposite directions.)
6. The network has enough arcs with sufficient capacity to enable all the flow generated
at the supply nodesto reach all the demand nodes.
7. The cost of the flow through each arc is proportionalto the amount of that flow, where
the cost per unit flow is known.
8. The objective is to minimize the total cost of sending the available supply through the
network to satisfy the given demand. (An alternative objective is to maximize the to-
tal profit from doing this.)

 

[Icosahedron]

That sounds exactly what we're looking for, Redwalker - and the algorithm that solves it 'extremely efficiently' is...?

(Sorry Ishmael, I haven't found the time to study and comment on your sheet yet.)

 

[redwalker]

That sounds exactly what we're looking for, Redwalker - and the algorithm that solves it 'extremely efficiently' is...?

(Sorry Ishmael, I haven't found the time to study and comment on your sheet yet.)

This is all yanked out of Hillier and Lieberman.

They seem to only cover linear problems in their text.

Now, linear problems are great -- they are fundamental to OR -- but ideally we would want broader types of problems.

Linear problems are normally solved by a family of methods called the "Simplex" methods -- if we bother to solve them by hand. Nowadays we frequently plug them into Excel's Solver and let the spreadsheet chug on them. Note that the spreadsheet will definitely not solve real-world problems of great depth, but it is good enough for a lot of small-business problems.

The network simplex method is a highly streamlined version of the simplex method for
solving minimum cost flow problems. As such, it goes through the same basic steps at
each iteration—finding the entering basic variable,determining the leaving basic variable,
and solving for the new BF solution—in order to move from the current BF solution to a
better adjacent one. However, it executes these steps in ways that exploit the special net-
work structure of the problem without ever needing a simplex tableau.
You may note some similarities between the network simplex method and the trans-
portation simplex method presented in Sec. 8.2. In fact, both are streamlined versions of
the simplex method that provide alternative algorithms for solving transportation prob-
lems in similar ways. The network simplex method extends these ideas to solving other
types of minimum cost flow problems as well.
In this section, we provide a somewhat abbreviated description of the network sim-
plex method that focuses just on the main concepts. We omit certain details needed for a
full computer implementation, including how to construct an initial BF solution and how
to perform certain calculations (such as for finding the entering basic variable) in the most
efficient manner. These details are provided in various more specialized textbooks, such
as Selected References 1, 2, 3, 5, and 8.
...
1. Ahuja, R. K., T. L. Magnanti, and J. B. Orlin: Network Flows:Theory, Algorithms, and Appli-
cations, Prentice-Hall, Englewood Cliffs, NJ, 1993.
2. Ball, M., T. L. Magnanti, C. Monma, and G. L. Nemhauser: Network Models, Elsevier, New
York, 1995.
3. Bazaraa, M. S., J. J. Jarvis, and H. D. Sherali: Linear Programming and Network Flows, 2d ed.,
Wiley, New York, 1990.
4. Dantzig, G. B., and M. N. Thapa: Linear Programming 1: Introduction, Springer, New York,
1997, chap. 9.
5. Glover, F., D. Klingman, and N. V. Phillips: Network Models in Optimization and Their Appli-
cations in Practice, Wiley, New York, 1992.
6. Hillier, F. S., M. S. Hillier, and G. J. Lieberman: Introduction to Management Science:A Mod-
eling and Case Studies Approach with Spreadsheets, Irwin/McGraw-Hill, Burr Ridge, IL, 2000,
chap. 7.
7. Magnanti, T. L., and R. T. Wong: “Network Design and Transportation Planning: Models and
Algorithms,”Transportation Science, 18:1–55, 1984.
8. Murty, K. G.: Network Programming, Prentice-Hall, Englewood Cliffs, NJ, 1992.

 

[redwalker]

So, yeah, I've been busy but I've been spending some spare time looking at ways to make a simple stochastic model of a market economy. I'm thinking that a modified "network flow problem" is the best bet. I'll keep working on this, but ideally I could put a simple version into spreadsheet format and then we could see if it fit with the other spreadsheet.

Edit:
Ideally, I could write some code that did network flow problems in general, and then apply that code to ecology and economy.

Flow networks also find applications in ecology: flow networks arise naturally when considering the flow of nutrients and energy between different organizations in a food web. The mathematical problems associated with such networks are quite different from those that arise in networks of fluid or traffic flow. The field of ecosystem network analysis, developed by Robert Ulanowicz and others, involves using concepts from information theory and thermodynamics to study the evolution of these networks over time.

http://en.wikipedia.org/wiki/Flow_network