Gallery#

A figure from every model of the zoo, each made by running the model with a fixed seed. The figures are drawn by tools/gallery/make_figures.py, one panel per model in tools/gallery/panels/; rerun it (python tools/gallery/make_figures.py, the same in bash and PowerShell) after changing a model.

Epidemiology#

Age-structured SEIR. Children, with the most contacts, peak first and highest.

Infectious share of three age groups over time

Vector-borne transmission. Outbreaks grow with mosquito density, in the order of the Ross-Macdonald R0.

Infectious hosts for three mosquito densities

Ecology#

Forest fire. The burnt share jumps at the percolation threshold.

Burnt share against tree density

Energy budgets. After a boom and bust the population settles on the carrying capacity set by the energy balance.

Population over time with its carrying capacity

Economics#

Order book. Mid-price returns have fat tails compared with a normal distribution.

Histogram of standardised returns on a log scale

Boltzmann wealth exchange. Random exchange of money gives the Boltzmann-Gibbs distribution.

Wealth distribution against the exact stationary law

Bouchaud-Mezard. The Gini settles on the value of the inverse-gamma law, higher for noisier returns.

Gini over time for three noise levels

Sociology and political science#

Deffuant. Opinions merge into a few clusters.

Opinion trajectories

Hegselmann-Krause. Final opinions against the confidence bound: many clusters, fewer, then consensus.

Final opinions against the confidence bound

Axelrod. More traits per feature leave more cultural regions.

Cultural regions against traits per feature

Transport and energy#

Nagel-Schreckenberg. The fundamental diagram, with and without random braking.

Flow against density for three dawdling probabilities

Bass diffusion. Adoption follows the Bass curve when mixing is complete, and lags on a sparse network.

Share adopted over time against the Bass equation

Submit your model#

The gallery is also open to community models built with Modelly that are not in the zoo. Open a pull request that adds your model’s entry to this page under a section “Community models”, with one PNG of at most 100 KB in docs/images/gallery/community/, and fill in the template below in the pull request description. A gallery entry does not need a validation test, but it must run from a seed and say how it was checked.

Title:            one line
Author(s):        names, and an ORCID if you have one
Field:            epidemiology / ecology / economics / sociology / transport / energy / other
Repository:       a public URL with the code, a licence and a README
Modelly version:  the version it was run with (python -c "import modelly; print(modelly.__version__)")
Reference:        the paper or report it reproduces or supports, if any
What it shows:    two or three sentences
How to run it:    the command that makes the figure, with its seed
How it was checked: an analytical result, a published figure, a comparison with another
                    implementation, or a test in the repository
Runtime:          on a laptop, for the figure

The maintainers run the command before merging. Models that are validated, small and of general interest may be invited into the zoo.