Add morph funcx (scrappy)

diffpy · sbillinge · Aug 1, 2025 · Jul 9, 2025 · Jul 9, 2025 · Jul 11, 2025
commit a3c9d0097bbb4e51034e3c8c8e67ff34fe9eb5d2
diff --git a/src/diffpy/morph/morphs/morphfuncx.py b/src/diffpy/morph/morphs/morphfuncx.py
@@ -0,0 +1,77 @@
+"""Class MorphFuncx -- apply a user-supplied python function to the
+x-axis."""
+
+from diffpy.morph.morphs.morph import LABEL_GR, LABEL_RA, Morph
+
+
+class MorphFuncx(Morph):
+    """Apply a custom function to the x-axis of the morph function.
+
+    General morph function that applies a user-supplied function to the
+    y-coordinates of morph data to make it align with a target.
+
+    Configuration Variables
+    -----------------------
+    function: callable
+        The user-supplied function that applies a transformation to the
+        y-coordinates of the data.
+
+    parameters: dict
+        A dictionary of parameters to pass to the function.
+
+    Returns
+    -------
+        A tuple (x_morph_out, y_morph_out, x_target_out, y_target_out)
+        where the target values remain the same and the morph data is
+        transformed according to the user-specified function and parameters
+        The morphed data is returned on the same grid as the unmorphed data
+
+    Example (FIX)
+    -------------
+    Import the funcy morph function:
+
+        >>> from diffpy.morph.morphs.morphfuncy import MorphFuncy
+
+    Define or import the user-supplied transformation function:
+
+        >>> def sine_function(x, y, amplitude, frequency):
+        >>>     return amplitude * np.sin(frequency * x) * y
+
+    Provide initial guess for parameters:
+
+        >>> parameters = {'amplitude': 2, 'frequency': 2}
+
+    Run the funcy morph given input morph array (x_morph, y_morph)and target
+    array (x_target, y_target):
+
+        >>> morph = MorphFuncy()
+        >>> morph.function = sine_function
+        >>> morph.funcy = parameters
+        >>> x_morph_out, y_morph_out, x_target_out, y_target_out =
+        ... morph.morph(x_morph, y_morph, x_target, y_target)
+
+    To access parameters from the morph instance:
+
+        >>> x_morph_in = morph.x_morph_in
+        >>> y_morph_in = morph.y_morph_in
+        >>> x_target_in = morph.x_target_in
+        >>> y_target_in = morph.y_target_in
+        >>> parameters_out = morph.funcy
+    """
+
+    # Define input output types
+    summary = "Apply a Python function to the y-axis data"
+    xinlabel = LABEL_RA
+    yinlabel = LABEL_GR
+    xoutlabel = LABEL_RA
+    youtlabel = LABEL_GR
+    parnames = ["function", "funcy"]
+
+    def morph(self, x_morph, y_morph, x_target, y_target):
+        """Apply the user-supplied Python function to the y-coordinates
+        of the morph data."""
+        Morph.morph(self, x_morph, y_morph, x_target, y_target)
+        self.x_morph_out = self.function(
+            self.x_morph_in, self.y_morph_in, **self.funcy
+        )
+        return self.xyallout