boxsimu

boxsimu is a simple simulation software that allows the user to model/simulate boxmodel-systems of intermediate complexity. It offers a user-friendly interface to define a system by instantiating different classes like Fluid, Variable, Flow, Flux, Process, Reaction, Box, BoxModelSystem. These instances can then be connected to each other. Once a system is defined with boxsimu, its temporal evolution can easily be simulated using the solve() function.

Getting Started

Prerequisites

Scientifc packages:

• numpy (1.10 or newer)
• matplotlib (1.5 or newer)
• jupyter (4.0 or newer)
• pandas (0.15 or newer)
• pint (0.8.1 or newer)

Other packages:

• attrdict (1.2 or newer)
• svgwrite (1.1 or newer)
• dill (2.7 or newer)

Installing

boxsimu can be installed using pip. On your console type in

pip install boxsimu

this should automatically compile all Cython files and copy all source files into the right directory. If the installation fails check if all of the above mentioned dependencies are met.

Code Example

The system we want to model consists of a freshwater lake that only has one inflow and one outflow. We want to simulate how the concentration of phosphate in this lake evolves over time. The system is defined in boxsimu with the following code:

import boxsimu 
from boxsimu import ur

freshwater = boxsimu.Fluid('freshwater', rho=1000*ur.kg/ur.meter**3)
po4 = boxsimu.Variable('po4')

lake = boxsimu.Box(
    name='lake',
    description='Little Lake',
    fluid=freshwater.q(m_water),
    variables=[po4.q(m_0)],
)

inflow = boxsimu.Flow(
    name='Inflow', 
    source_box=None,
    target_box=lake,
    rate=flow_rate,
    tracer_transport=True,
    concentrations={po4: 3e-1 * ur.gram / ur.kg}, 
)
outflow = boxsimu.Flow(
    name='Outflow',
    source_box=lake,
    target_box=None,
    rate=flow_rate,
    tracer_transport=True,
)

system = boxsimu.BoxModelSystem(
    name='lake_system', 
    description='Simple Lake Box Model',
    boxes=[lake,], 
    flows=[inflow, outflow,],
)

For an explanation of the code see Tutorial Part 1. The system's temporal evolution can then be simulated and visualized:

solution = system.solve(total_integration_time=800*ur.day, dt=1*ur.day)
solution.plot_variable_concentration(variable=po4)

This results in the following plot:

Contributing

You have a question about the package or you would like to have a certain feature implemented? Open an issue!

Authors

• Mathias Aschwanden

License

This project is licensed under the MIT License - see the LICENSE.md file for details