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…dentical factors into a single JacobianFactor
…TestProjectionFactor` wrapper.
…maps and automatically deduce factor constructor signatures using metaprogramming.
… several `BatchFactor` constructors.
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Pull Request Overview
This PR introduces a new BatchFactor class that aggregates multiple identical factors into a single container, optimizing memory allocation through single malloc operations and creating large single-malloc Jacobian factors during linearization. This is designed to improve performance for Structure-from-Motion and SLAM applications with many similar factors.
Key Changes
- New
BatchFactortemplate class that wraps collections of factors - Map-based constructors for convenient factor batching
- Optimized linearization that produces a single JacobianFactor
- Test suite demonstrating usage with ProjectionFactor and BetweenFactor
- Timing example in timeSFMBAL.cpp comparing regular and batched approaches
Reviewed Changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 11 comments.
| File | Description |
|---|---|
| gtsam/nonlinear/BatchFactor.h | New header file defining the BatchFactor template class with constructors, linearization, and helper methods |
| gtsam/nonlinear/tests/testBatchFactor.cpp | New test file with three test cases covering different constructor patterns and factor types |
| timing/timeSFMBAL.cpp | Modified to add BatchFactor usage example alongside existing conventional factor graph approach |
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Author
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@ProfFan FYI |
Compare with Metis Dramatically simplified Hessian path (and way faster!) Add linearize time Hessian! Kill "fast" path revert that More micro-optimization ScratchMatrix offsets_ added a Value cache feat: Optimize BatchFactor linearization by enabling zero-malloc Jacobian computation via OptionalJacobian stride support. refactor: optimize BatchFactor key and dimension indexing. refactor: cache factor-specific key indices in BatchFactor for improved linearization and enable LM sequential Cholesky solver with summary verbosity. refactor: Pre-calculate key dimensions and indices in BatchFactor, add vector constructors, and enable LM parameters in timeSFMBAL. Address comments
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WIP: a new non-linear factor that collects many smaller factors but stores them with one malloc, and also creates a large single-malloc Jacobian factor.
Did some more work, including trying to linearize to hessian, and I ran on a larger problem. Verdict: whatever we gain in linearization dwarfs compared to slower elimination:
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