Equilibration tolerances

[bobmyhill]

This pull request introduces improvements to the handling of solver tolerances in the equilibration routines, making them more flexible and robust. The changes allow the tolerance parameter (tol) to be specified as either a single float or a per-parameter array, with sensible defaults provided when not specified. The documentation and tests have been updated to reflect and validate these changes.

Enhancements to tolerance handling:

• The tol parameter in equilibrate and related functions can now be a float or a 1D numpy array, with default tolerances set for each parameter if tol is not provided. This allows for finer control and clearer defaults for pressure, temperature, phase amounts, and compositional vectors. [1] [2] [3]
• Validation logic in nonlinear_solvers.py ensures that array tolerances are 1D and match the number of parameters, raising informative errors if mismatched.

Documentation and usability improvements:

• The docstrings for equilibrate and related functions have been updated to clearly describe the new behavior and default values for the tolerance parameter.

Testing and backward compatibility:

• New tests verify correct error handling for invalid tolerance inputs and ensure that valid cases work as expected.
• Calls to equilibrate in the SLB2024 benchmark script have been updated to use the new default tolerance behavior, removing explicit tol arguments for simplicity. [1] [2] [3] [4] [5]

[Copilot]

Pull Request Overview

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