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Visualization

Visualizing the experiment topology is crucial for verifying dependencies and understanding the data flow in complex pipelines before execution.

Using the CLI​

Use repx viz to generate a graph of the experiment topology.

repx viz --lab ./result
# Generates topology.png by default
Experiment Topology

Options​

  • --output <file> / -o: Specify the output filename.
  • --format <fmt>: Specify the format (e.g., svg, png, pdf, dot).
repx viz --lab ./result -o my-graph.svg --format svg

Interpreting the Graph​

  • Nodes: Each node represents a Job (a concrete instance of a Stage).
  • Edges: Arrows represent Data Dependencies (output of A -> input of B).
  • Clusters: Jobs are grouped by their Run Name (e.g., simulation, analysis).
  • Shapes:
    • Box: Simple Stage.
    • Subgraph Cluster: Scatter-Gather groups. These render as a cluster containing:
      • Trapezium: Scatter phase node.
      • Box (indigo): Step nodes, connected according to the step DAG dependencies.
      • Inverted Trapezium: Gather phase node.
      • Internal edges show the step DAG flow: scatter → root steps → ... → sink step → gather.

Requirements​

The visualization tool relies on Graphviz to render the graphs.

Nix (Recommended): The repx flake provides a devShell that includes Graphviz.

nix develop

System Install: If running outside Nix:

  • Ubuntu/Debian: sudo apt install graphviz
  • macOS: brew install graphviz