Table 1.
Model parameters and variables, their notation, level of operation and values.
| variable/parameter | notation | level | description | value |
|---|---|---|---|---|
| nutritional state | NS | individual | an individual's nutritional state, as tracked by its (p, c) position in the nutrient space, and denoting total intake of the two nutrients | variable (p, c) |
| intake target | IT | global | an individual's IT is the (p, c) coordinate in the nutrient space that maximizes F | variable (p, c) |
| distance to the IT | D | individual | the Euclidean distance between an individual's NS and the IT | variable |
| food rail | V | global | the nutritional composition of a food in terms of the amount of carbohydrate (c) in a given food relative to single equivalent unit of protein (p) | 1, 3, 0.333, 16 and 0.667 (figure 1) |
| appetite | A | individual | the amount of a given food that an individual would consume to minimize D | variable |
| ideal food rail | αideal | individual | the angle of a hypothetical ideal food rail connecting an individual's NS with their IT | variable |
| meal size | φ | global | the maximum amount of food that an individual is able to consume at a given time | 0.0368 |
| social influence | σ | individual | the weight of the social interactions relative to the individual orientation when moving | 0, 0.005, 0.01, 0.025, 0.2 |
| noise weight | η | individual | the weight of a random unit vector relative to vectors corresponding to social and individual influences during movement | fixed at 0.0025, 0.0275 or 0.0525; or variable (see §2a(iii) Movement rules) |
| higher noise limit | U | individual | upper bound value when calculating the variable noise as a function of D | 0.0525 |
| lower noise limit | L | individual | lower bound value when calculating the variable noise as a function of D | 0.0025 |
| noise decrease constant | K | individual | slope constant when calculating the variable noise as a function of D | 0.0075 |
| repulsion range | Rr | individual | range at which neighbours exert a repulsion force on an individual | 1 |
| alignment range | Ra | individual | range at which an individual aligns with its neighbours | 6 |
| attraction range | Rp | individual | range at which an individual is attracted to its neighbours | 56 |
| proportion of individuals within alignment range psoc | psoc | global | the proportion of moving individuals who have at least one neighbour with alignment range Ra or closer | variable |
| spatial coordinates of an individual | Λ | individual | the {x, y} spatial coordinates of an individual | variable |