.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_examples/Ex_cross_constraints.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_auto_examples_Ex_cross_constraints.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_Ex_cross_constraints.py:


Cross-Method Structural Constraints
===================================

This example shows how to:
1. Build structural weights from an SRT velocity model.
2. Apply those weights to an ERT smoothness matrix.
3. Build a cross-gradient operator between two models.

.. GENERATED FROM PYTHON SOURCE LINES 10-70

.. code-block:: default



    import numpy as np
    from scipy.sparse import diags

    from PyHydroGeophysX.inversion.cross_constraints import StructuralConstraint


    class _DummyMesh:
        """Minimal mesh-like object for demonstration."""

        def __init__(self, n_cells: int):
            self._n_cells = n_cells

        def cellCount(self):
            return self._n_cells

        def cellCenters(self):
            x = np.linspace(0.0, 100.0, self._n_cells)
            z = np.linspace(0.0, 30.0, self._n_cells)
            return np.column_stack((x, z))


    def run_example():
        n_cells = 60
        mesh = _DummyMesh(n_cells)

        velocity = np.linspace(1200.0, 3200.0, n_cells)
        velocity[25:35] += 1400.0

        conductivity = np.linspace(0.01, 0.2, n_cells)
        conductivity[20:30] *= 2.5

        boundary_weights = StructuralConstraint.from_velocity_model(
            velocity_model=velocity,
            mesh=mesh,
            gradient_threshold=0.3,
        )

        # Dummy smoothness matrix with nearest-neighbor differences.
        w = np.ones(n_cells)
        Wm = diags([-w[:-1], w[:-1]], offsets=[0, 1], shape=(n_cells - 1, n_cells)).tocsr()
        Wm_weighted = StructuralConstraint.apply_structural_weights_to_Wm(Wm, boundary_weights)

        cross_op = StructuralConstraint.build_cross_gradient_operator(
            mesh=mesh,
            model_a=np.log10(1.0 / conductivity),
            model_b=velocity,
        )

        print("Cross-constraint example complete")
        print(f"  smoothness matrix shape: {Wm.shape}")
        print(f"  weighted smoothness shape: {Wm_weighted.shape}")
        print(f"  cross-gradient operator shape: {cross_op.shape}")

        return Wm_weighted, cross_op


    if __name__ == "__main__":
        run_example()


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.000 seconds)


.. _sphx_glr_download_auto_examples_Ex_cross_constraints.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example




    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: Ex_cross_constraints.py <Ex_cross_constraints.py>`

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: Ex_cross_constraints.ipynb <Ex_cross_constraints.ipynb>`