remove unnecessary interpolation function, edit test for compute_cve for different xtypes

Author: yucongalicechen

src/diffpy/labpdfproc/functions.py

@@ -244,39 +244,6 @@ def _cve_method(method):
     return methods[method]
 
 
-def interpolate_to_xtype_grid(cve_do, xtype):
-    f"""
-    interpolates the cve grid to the xtype user specified
-
-    Parameters
-    ----------
-    cve_do Diffraction_object
-      the diffraction object that contains the cve to be applied
-    xtype str
-      the quantity on the independent variable axis, allowed values are {*XQUANTITIES, }
-
-    Returns
-    -------
-    the new diffraction object with interpolated cve curves
-    """
-    if xtype == "tth":
-        return cve_do
-
-    orig_grid, orig_cve = cve_do.on_tth[0], cve_do.on_tth[1]
-    new_grid = cve_do.tth_to_q()
-    new_cve = np.interp(new_grid, orig_grid, orig_cve)
-    new_cve_do = Diffraction_object(wavelength=cve_do.wavelength)
-    new_cve_do.insert_scattering_quantity(
-        new_grid,
-        new_cve,
-        xtype,
-        metadata=cve_do.metadata,
-        name=cve_do.name,
-        scat_quantity="cve",
-    )
-    return new_cve_do
-
-
 def compute_cve(diffraction_data, mud, method="polynomial_interpolation", xtype="tth"):
     f"""
     compute and interpolate the cve for the given diffraction data and mud using the selected method
@@ -298,11 +265,10 @@ def compute_cve(diffraction_data, mud, method="polynomial_interpolation", xtype=
     """
 
     cve_function = _cve_method(method)
-    cve_do_on_global_tth = cve_function(diffraction_data, mud)
-    cve_do_on_global_xtype = interpolate_to_xtype_grid(cve_do_on_global_tth, xtype)
+    cve_do_on_global_grid = cve_function(diffraction_data, mud)
     orig_grid = diffraction_data.on_xtype(xtype)[0]
-    global_xtype = cve_do_on_global_xtype.on_xtype(xtype)[0]
-    cve_on_global_xtype = cve_do_on_global_xtype.on_xtype(xtype)[1]
+    global_xtype = cve_do_on_global_grid.on_xtype(xtype)[0]
+    cve_on_global_xtype = cve_do_on_global_grid.on_xtype(xtype)[1]
     newcve = np.interp(orig_grid, global_xtype, cve_on_global_xtype)
     cve_do = Diffraction_object(wavelength=diffraction_data.wavelength)
     cve_do.insert_scattering_quantity(

tests/test_functions.py

@@ -3,13 +3,7 @@
 import numpy as np
 import pytest
 
-from diffpy.labpdfproc.functions import (
-    CVE_METHODS,
-    Gridded_circle,
-    apply_corr,
-    compute_cve,
-    interpolate_to_xtype_grid,
-)
+from diffpy.labpdfproc.functions import CVE_METHODS, Gridded_circle, apply_corr, compute_cve
 from diffpy.utils.scattering_objects.diffraction_objects import Diffraction_object
 
 params1 = [
@@ -78,44 +72,23 @@ def _instantiate_test_do(xarray, yarray, xtype="tth", name="test", scat_quantity
 
 
 params4 = [
-    ([np.array([30, 60, 90]), np.array([1, 2, 3]), "tth"], [np.array([30, 60, 90]), np.array([1, 2, 3]), "tth"]),
-    (
-        [np.array([30, 60, 90]), np.array([1, 2, 3]), "q"],
-        [np.array([2.11195, 4.07999, 5.76998]), np.array([1, 1, 1]), "q"],
-    ),
+    (["tth"], [np.array([90, 90.1, 90.2]), np.array([0.5, 0.5, 0.5]), "tth"]),
+    (["q"], [np.array([5.76998, 5.77501, 5.78004]), np.array([0.5, 0.5, 0.5]), "q"]),
 ]
 
 
 @pytest.mark.parametrize("inputs, expected", params4)
-def test_interpolate_xtype(inputs, expected, mocker):
-    expected_cve_do = _instantiate_test_do(
-        expected[0],
-        expected[1],
-        xtype=expected[2],
-        name="absorption correction, cve, for test",
-        scat_quantity="cve",
-    )
-    input_cve_do = _instantiate_test_do(
-        inputs[0],
-        inputs[1],
-        xtype="tth",
-        name="absorption correction, cve, for test",
-        scat_quantity="cve",
-    )
-    actual_cve_do = interpolate_to_xtype_grid(input_cve_do, xtype=inputs[2])
-    assert actual_cve_do == expected_cve_do
-
-
-def test_compute_cve(mocker):
+def test_compute_cve(inputs, expected, mocker):
     xarray, yarray = np.array([90, 90.1, 90.2]), np.array([2, 2, 2])
     expected_cve = np.array([0.5, 0.5, 0.5])
     mocker.patch("diffpy.labpdfproc.functions.TTH_GRID", xarray)
     mocker.patch("numpy.interp", return_value=expected_cve)
     input_pattern = _instantiate_test_do(xarray, yarray)
-    actual_cve_do = compute_cve(input_pattern, mud=1)
+    actual_cve_do = compute_cve(input_pattern, mud=1, method="polynomial_interpolation", xtype=inputs[0])
     expected_cve_do = _instantiate_test_do(
-        xarray,
-        expected_cve,
+        expected[0],
+        expected[1],
+        expected[2],
         name="absorption correction, cve, for test",
         scat_quantity="cve",
     )