I'm a big fan of Graphviz. My old team created a library called Loman, which we open-sourced, which uses DAGs to represent calculations. Each node represents a part of the calculation and contains a value, similar to a cell in an spreadsheet, and Loman tracks what is stale as you update inputs. Loman includes built in support for creating diagrams using Graphviz. In our quant research we have found that invaluable when revisiting old code, as it allows you to quickly see the structure and meaning of graphs with hundreds of nodes, containing thousands of lines of code.
We've found it quite useful for quant research, and in production it works nicely because you can serialize entire computation graph which gives an easy way to diagnose what failed and why in hundreds of interdependent computations. It's also useful for real-time displays, where you can bind market and UI inputs to nodes and calculated nodes back to the UI - some things you want to recalculate frequently, whereas some are slow and need to happen infrequently in the background.
We've found it quite useful for quant research, and in production it works nicely because you can serialize entire computation graph which gives an easy way to diagnose what failed and why in hundreds of interdependent computations. It's also useful for real-time displays, where you can bind market and UI inputs to nodes and calculated nodes back to the UI - some things you want to recalculate frequently, whereas some are slow and need to happen infrequently in the background.
[1] Github: https://github.com/janushendersonassetallocation/loman
[2] Docs: https://loman.readthedocs.io/en/latest/
[3] Examples: https://github.com/janushendersonassetallocation/loman/tree/...