ymmsl2svg: Visualize yMMSL workflows

Visualize yMMSL workflow as Scalable Vector Graphics (SVG).

This tool takes a yMMSL model (from a v0.2 yMMSL file) and generates an SVG image to represent it.

Features

• Visualize the coupling diagram for yMMSL (sub)models
• Call/release (a.k.a. macro-micro) coupling
• Dispatch coupling
• Visualize component ports: F_INIT ports are drawn on the left side of a component as an open diamond, O_F ports on the right side as a closed diamond, and O_I and S ports on the bottom as respectively a closed and an open circle.
• Visualize model ports: F_INIT ports on the left side of the model, O_F ports on the right side. Model O_I and S ports are not (yet) supported.
• Visualize "multi-cast" conduits, where one output port sends to multiple input ports.
• Draw conduits with filters.

Note that not ymmsl2svg cannot visualize all valid yMMSL configurations, see Roadmap for a brief overview of missing functionality.

Examples

Click to open the image in a new tab and enable interactive features, such as tooltips with the port name when hovering over a port.

Usage

ymmsl2svg depends on a development version of ymmsl-python. Therefore we don't have a package available on PyPI yet. Until the upstream functionality is available in a ymmsl-python release, we recommend to run ymmsl2svg with uvx (see the uv installation instructions):

# Create 'workflow.svg' image from the root model in 'workflow.ymmsl'
uvx --from git+https://github.com/multiscale/ymmsl2svg.git ymmsl2svg workflow.ymmsl -o workflow.svg

# Show supported options and settings
uvx --from git+https://github.com/multiscale/ymmsl2svg.git ymmsl2svg --help

Roadmap

ymmsl2svg currently cannot visualize any valid yMMSL model yet, this section provides a brief overview of missing features that we would like to implement in the future:

• Missing yMMSL features
  • Visualize interact coupling diagrams and time-scale bridges. ¹
  • Visualize components with multiple sub-timelines. ¹
  • Visualize O_I and S ports of models. ²
• Command Line Interface
  • Allow selecting a specific model in the yMMSL configuration (currently only the root model is visualized).
  • Allow changing settings / parameters from the Command Line interface.
• Additional features
  • Interactive highlight of connected conduits when hovering over components or ports.
  • Add an option to draw parallel components under eachother.

1: The SVG generation currently fails for models containing this.
2: An SVG is generated for models containing this, but a warning is logged and the visualization is not complete.

Legal

Copyright 2026 ITER Organization. The code in this repository is licensed under the Apache-2.0 license