.. _auto_curve_get_linear_fit_r2:

*GET R2 FIT TIME-HISTORY*
=========================

Computes a rolling R² (coefficient of determination) time-history for a curve by fitting a polynomial of a given order over a sliding window. Use this worker to quantify how linearly (or polynomially) consistent a signal is across time, producing a curve of R² values at each window position.

When to use
-----------

Classification: **process**.

Tagged: ``curve``, ``goodness_of_fit``, ``linear_fit``, ``polynomial_fit``, ``r2``, ``sliding_window``, ``time_history``.

Inputs
------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20 20 20

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Base Curve
     - base_curve
     - vector
     - —
     - 
     - Input time-history curve (x/y vector) over which the rolling polynomial R² fit is computed; must be a valid d3VIEW curve object.
   * - Window Size
     - window_size
     - string
     - 0.01
     - 
     - Width of the sliding window in the same x-axis units as the base curve (default 0.01); controls how many points are included in each local polynomial fit — smaller values capture finer local behaviour.
   * - Number Of Digitize Points
     - num_dig
     - string
     - 1000
     - 
     - Number of evenly-spaced digitization points used to resample the base curve before processing (default 1000); the actual resolution used is the maximum of this value and the original curve point count.
   * - Order
     - order
     - string
     - 1
     - 
     - Polynomial order used for the least-squares fit within each window (default 1 = linear); increase to 2 or higher to measure goodness-of-fit for higher-degree polynomial trends.

Outputs
-------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20

   * - Label
     - ID
     - Type
     - Description
   * - R2 history
     - curve_get_linear_fit_output_1
     - vector
     - Output time-history curve (x/y vector) where each y-value is the R² coefficient of determination of the polynomial fit evaluated at the corresponding window position; values range from 0 (no fit) to 1 (perfect fit).

Disciplines
-----------

- data.curve.transform
- data.signal_processing
- data.statistics

Runnable example
----------------

A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: `/api/workflow/example?id=curve_get_linear_fit_r2 <https://www.d3view.com/api/workflow/example?id=curve_get_linear_fit_r2>`_

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   Auto-generated from <code>transformation</code> schema. Worker id: <code>curve_get_linear_fit_r2</code>. Schema hash: <code>87c5056cb83d</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
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