Add trimming module to source modelling

[lispandfound]

Adds a module for trimming slip arrays to source modelling.

Slip trimming is needed for SRCMOD models (and other inversion based models) because researchers will often impose a much larger dimension on the fault than is physical. Trimming improves the performance of the models against common relationships (Mw-Area, Avg. slip, geometry based methods like RRup-IM, RJB-IM, etc).

Both the implemented methods (the basic Sommerville method, and the Thingbaijam method) take slip arrays in the shape (nstk, ndip) and produce boolean masks over the arrays. So slip[mask] will return a new array containing only the masked slip.

[gemini-code-assist]

Summary of Changes

Hello @lispandfound, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a new module dedicated to refining earthquake source models by trimming slip arrays. The functionality aims to improve the physical consistency and accuracy of models, particularly those based on inversion, by removing low-slip regions from oversized fault dimensions. This enhancement helps align model outputs with established geophysical relationships.

Highlights

• New Trimming Module: Introduces a new trim module within source_modelling to handle slip array trimming, essential for refining earthquake source models.
• Implemented Trimming Methods: Adds two distinct slip trimming methodologies: the Sommerville method and the Thingbaijam method, both designed to generate boolean masks for slip arrays based on scientific criteria.
• Utility Functions: Includes utility functions such as autocorrelation_dimension and trim_array_to_target_length to support the main trimming algorithms by calculating characteristic lengths and spatial boundaries.
• Comprehensive Testing: Adds a new test file tests/test_trim.py with comprehensive unit and property-based tests to ensure the correctness and robustness of all new trimming functionalities.

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[gemini-code-assist]

Code Review

This pull request adds a new trim module to source_modelling for trimming slip arrays, which is a valuable addition. The code includes two trimming methods, sommerville and thingbaijam, along with unit tests. My review focuses on improving correctness and maintainability. I've identified a few issues, including a potential division-by-zero error, a logic bug in one of the trimming helper functions, and several opportunities to improve code clarity and adhere to Python conventions. The provided tests are a good start, but they don't catch the logic bug I've pointed out. Addressing these points will make the new module more robust and easier to maintain.

[lispandfound]

Had to appease the type checker with some minor tweaks to return types.

[Copilot]

Pull Request Overview

This pull request adds a new trimming module to source modelling for analyzing and trimming slip arrays on fault models. The module provides two trimming methods (Somerville and Thingbaijam) to improve performance of source models against common seismological relationships.

• Implements Somerville and Thingbaijam slip trimming methods for removing low-slip regions
• Adds autocorrelation dimension calculations for characteristic length scale determination
• Includes comprehensive test coverage with property-based testing using Hypothesis

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
source_modelling/trim.py	New module implementing slip array trimming algorithms and autocorrelation calculations
tests/test_trim.py	Comprehensive test suite for the trimming module with unit and property-based tests
tests/test_sources.py	Minor update to use shapely.equals instead of geometry.equals method
tests/test_gsf.py	Minor updates to use shapely.contains instead of geometry.contains method
source_modelling/sources.py	Code formatting improvements and type annotation update for geometry property

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[AndrewRidden-Harper]

looks good. I made a couple of suggestions for comments

[AndrewRidden-Harper]

Suggested change

	# just need to check which smallest, as that one *definitely*
	# just need to check which is smallest, as that one *definitely*

[AndrewRidden-Harper]

Suggested change

	# So the mask will include all rows from top of region down
	# So the mask will include all rows from the top of the region down