More navigation docs

[dellaert]

@p-zach I was able to generate several more notebooks almost perfectly using Google AI studio, with Gemini 2.5. I uploaded the navigation directory using repomix (compressed code), and then also pasted the json from AHRSFactor.ipynb. The prompt was then:

I already have a notebook describing the AHRSFactor, see below. Could you produce notebooks for the other classes involved with the IMU factors? Once notebook per class.

The output was almost perfect. I used the text editor to paste the json, and had to correct one formula. I also corrected its code style, saying:

In the last code example, please use from gtsam import , and also use GTSAMs from gtsam.symbol_shorthand import X,V,B so you can directly use X(0) etc, rather than define more variables. Just give me the code, I can paste it in the notebook

This is wild 🤯 ♊.

Also updated navigation.md with an overview and mermaid diagrams. More editing there to my linking, but again ♊ magic 🪄 .

classDiagram
    direction TD

    class PreintegrationBase {
        <<Abstract>>
        +imuBias::ConstantBias biasHat_
        +double deltaTij_
        +resetIntegration()*
        +integrateMeasurement()*
        +biasCorrectedDelta()*
        +predict()
        +computeError()
    }

    class ManifoldPreintegration {
        +NavState deltaXij_
        +update()
    }
    ManifoldPreintegration --|> PreintegrationBase : implements

    class TangentPreintegration {
        +Vector9 preintegrated_
        +update()
    }
    TangentPreintegration --|> PreintegrationBase : implements

    class PreintegratedImuMeasurements {
        +Matrix9 preintMeasCov_
    }
    PreintegratedImuMeasurements --|> ManifoldPreintegration : inherits
    PreintegratedImuMeasurements --|> TangentPreintegration : inherits

    class PreintegratedCombinedMeasurements {
       +Matrix preintMeasCov_ (15x15)
    }
    PreintegratedCombinedMeasurements --|> ManifoldPreintegration : inherits
    PreintegratedCombinedMeasurements --|> TangentPreintegration : inherits

    class ImuFactor {
        Pose3, Vector3, Pose3, Vector3, ConstantBias
        +evaluateError(...) Vector9
    }
    ImuFactor ..> PreintegratedImuMeasurements : uses
    class ImuFactor2 {
        NavState, NavState, ConstantBias
        +evaluateError(...) Vector9
    }
    ImuFactor2 ..> PreintegratedImuMeasurements : uses


    class CombinedImuFactor {
        Pose3, Vector3, Pose3, Vector3, ConstantBias
         +evaluateError(...) Vector (15)
    }
    CombinedImuFactor ..> PreintegratedCombinedMeasurements : uses

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[dellaert]

Update: I added 8 more classes, still a bit manual :-( takes me about 15 mins per class on average to check everything. The generated code was good to find out that several classes and/or methods were not yet wrapped, so that was part of the work.

[p-zach]

Nice! All looks good to me.