Grevling

Welcome to Grevling. Grevling (the Norwegian word for “Badger”) is a tool for parametrizing workflows. Think of Grevling as solving a problem similar to Make.

Typical use case

You’re a scientist working with a numerical simulation tool. This tool is impressive, it has a large variety of options and a daunting but well-structured input file format. You wish to generate and simulate a large family of similar but different cases. Many of these cases require pre- and post-processing steps as well. In addition, you want to collect information from each run and store them in a table, maybe also make some plots.

At some point, setting up the input for each case by hand becomes intractable. You could script it, say, in Bash, but Bash is nobody’s favorite tool. You already have a number of such scripts lying around, each of them with subtle differences, and you can’t remember which one does what anyway.

Instead, you can configure your setup with Grevling. Grevling will be able to:

• generate the inputs for each case

• run the simulator with pre- and post-processing

• gather data from each run and collect them in a data frame

• produce plots

Design goals

Grevling should

• never require support from third-party tools: it should not be necessary for other programs to know that they are being run by Grevling,

• be fully declarative: no more ad-hoc scripting (although technically you can this in Grevling, the design should not encourage it).