Parameters of the VirtualLabs:
Population structure
by Christoph Hauert, Version 1.0, December 2006.
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 VirtualLabs
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 » Structure
Interaction vs reproduction graphs.
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Populations have different characteristic structures determined by the type of interactions of one player with other members of the populations.
 Structure:

 meanfield/wellmixed populations:
 Well mixed population without any structures, i.e. groups or pairwise encounters are formed randomly. This is often called the meanfield approximation.
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 linear lattice:
 The players are arranged on a straight line  that is actually on a ring in order to reduce finite size and boundary effects  and interact with equal numbers of neighbors to their left and right.
 square lattice:
 All players are arranged on a rectangular lattice with periodic boundary conditions. The neighborhood size may be four (von Neumann) or eight (Moore neighborhood).
 hexagonal lattice:
 The players are arranged on a hexagonal or honeycomb lattice interacting with their six nearest neighbors.
 triangular lattice:
 The players are arranged on a triangular lattice interacting with their three nearest neighbors.
 linear small world network:
 Small world network with an underlying structure of a linear lattice (see above), i.e. first the population is initialized with a linear lattice geometry and then a certain fraction of bonds (see Frac new joints below) is randomly rewired. Note that the rewiring process leaves the connectivity of the players alone.
 square small world network:
 Small world network with an underlying structure of a rectangular lattice (see above).
 hexagonal small world network:
 Small world network with an underlying structure of a hexagonal or honeycomb lattice (see above).
 triangular small world network:
 Small world network with an underlying structure of a triangular lattice (see above).
 random graphs:
 Randomly drawn bonds/connections between players. The neighborhood size determines the average number of bonds (average connectivity) of one player, i.e. the players interact with different numbers of other individuals.
 random regular graphs:
 The structure of random regular graphs is similar to random graphs with the additional constraint that each player has an equal number of interaction partners.
 Neighborhood size:
 Determines the number of potential interaction partners. This corresponds to the connectivity of a player. In the case of random graphs, this specifies the average number of interaction partners.
 Frac new joints:
 Fraction of bonds that get randomly rewired to obtain a small world network out of some underlying regular lattice. Note that fractions close to one will require an enormous number of rewired bonds.