.. _auto_curves_lookup_xvalueat:

* COMPUTE THE VALUE OF X FOR A GIVEN Y VALUE*
=============================================

Given one or more curves and a target Y value, this worker performs an inverse lookup to find the corresponding X value(s) where the curve crosses that Y level. Use it when you need to extract a threshold crossing time, displacement, or other X-axis quantity at a prescribed response level.

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

Classification: **process**.

Tagged: ``curve``, ``interpolation``, ``inverse_lookup``, ``lookup``, ``threshold_crossing``, ``x_at_y``.

Inputs
------

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

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Curves
     - curves
     - vector
     - —
     - 
     - One or more input curves (X-Y pairs) on which the inverse lookup is performed; accepts multiple curves simultaneously.
   * - Y Value
     - y_value
     - float
     - —
     - 
     - The target Y value (float) at which the corresponding X value is to be found via interpolation; must lie within the Y range of the supplied curves.
   * - Format
     - format
     - string
     - %s
     - 
     - Printf-style format string (e.g. '%s', '%.4f') controlling how the resulting X value is rendered in the output; leave as default '%s' for general-purpose string formatting.

Outputs
-------

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

   * - Label
     - ID
     - Type
     - Description
   * - curve_lookup_xvalueat_output_1
     - curve_lookup_xvalueat_output_1
     - dataset
     - Dataset containing the computed X value(s) corresponding to the specified Y value for each input curve, one row per curve.

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

- data.curve.pair
- data.curve.transform

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

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

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   Auto-generated from <code>transformation</code> schema. Worker id: <code>curves_lookup_xvalueat</code>. Schema hash: <code>45df0ffc598a</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>