Add profile ReflectionProfilePseudoVoigtTCH with TCH instead of explicit Eta mixing

news/tch-pv-profile.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* Expose reflection profile ReflectionProfilePseudoVoigtTCH
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

src/extensions/reflectionprofile_ext.cpp

@@ -139,6 +139,26 @@ void wrap_reflectionprofile()
               bp::arg("eta1") = 0),
              "Set the isotropic pseudo-Voigt profile parameters.");
 
+    class_<ReflectionProfilePseudoVoigtTCH, bases<ReflectionProfile> >(
+        "ReflectionProfilePseudoVoigtTCH", init<>())
+        .def(init<const ReflectionProfilePseudoVoigtTCH &>(bp::arg("old")))
+        .def("CreateCopy", &ReflectionProfilePseudoVoigtTCH::CreateCopy,
+             return_value_policy<manage_new_object>(),
+             "Return an independent copy of this profile.")
+        .def("SetProfilePar",
+             (void (ReflectionProfilePseudoVoigtTCH::*)(
+                 const REAL, const REAL, const REAL, const REAL,
+                 const REAL, const REAL, const REAL, const REAL))
+                 &ReflectionProfilePseudoVoigtTCH::SetProfilePar,
+             (bp::arg("fwhmCagliotiW"), bp::arg("fwhmCagliotiU") = 0,
+              bp::arg("fwhmCagliotiV") = 0,
+              bp::arg("fwhmLorentzX") = 0,
+              bp::arg("fwhmLorentzY") = 0,
+              bp::arg("fwhmLorentzZ") = 0,
+              bp::arg("fwhmScherrerP") = 0,
+              bp::arg("scherrerLGmix") = 1),
+             "Set the TCH pseudo-Voigt U, V, W, X, Y, Z, P and LGmix parameters.");
+
     class_<ReflectionProfilePseudoVoigtAnisotropic,
            bases<ReflectionProfile> >(
         "ReflectionProfilePseudoVoigtAnisotropic", init<>())

src/pyobjcryst/reflectionprofile.py

@@ -20,10 +20,10 @@
 ``XMLOutput`` / ``XMLInput`` and ``CreateCopy``. ``GetProfile``
 accepts a Python sequence or numpy array for ``x``.
 
-Concrete isotropic and anisotropic pseudo-Voigt profiles can be installed
-with ``PowderPatternDiffraction.SetProfile``. The diffraction component
-stores an independent copy, so one configured profile can be reused as a
-template for multiple phases::
+Concrete empirical isotropic, TCH isotropic, and anisotropic pseudo-Voigt
+profiles can be installed with ``PowderPatternDiffraction.SetProfile``. The
+diffraction component stores an independent copy, so one configured profile
+can be reused as a template for multiple phases::
 
     from pyobjcryst.reflectionprofile import (
         ReflectionProfilePseudoVoigtAnisotropic,
@@ -67,6 +67,7 @@
 __all__ = [
     "ReflectionProfile",
     "ReflectionProfilePseudoVoigt",
+    "ReflectionProfilePseudoVoigtTCH",
     "ReflectionProfilePseudoVoigtAnisotropic",
     "ReflectionProfileType",
 ]
@@ -75,5 +76,6 @@
     ReflectionProfile,
     ReflectionProfilePseudoVoigt,
     ReflectionProfilePseudoVoigtAnisotropic,
+    ReflectionProfilePseudoVoigtTCH,
     ReflectionProfileType,
 )

tests/test_reflectionprofile.py

@@ -11,6 +11,7 @@
     ReflectionProfile,
     ReflectionProfilePseudoVoigt,
     ReflectionProfilePseudoVoigtAnisotropic,
+    ReflectionProfilePseudoVoigtTCH,
 )
 
 
@@ -73,6 +74,73 @@ def test_concrete_pseudo_voigt_profiles(self):
             },
         )
 
+    def test_tch_profile_width_and_limits(self):
+        """TCH derives one common FWHM and reaches both pure limits."""
+        profile = ReflectionProfilePseudoVoigtTCH()
+        self.assertFalse(profile.IsAnisotropic())
+        self.assertEqual(
+            {"U", "V", "W", "X", "Y", "Z", "P", "LGmix"},
+            {profile.GetPar(i).GetName() for i in range(profile.GetNbPar())},
+        )
+
+        center = np.deg2rad(30.0)
+        hg = np.deg2rad(0.08)
+        hl = np.deg2rad(0.04)
+        profile.SetProfilePar(hg**2, fwhmLorentzZ=hl)
+        h = (
+            hg**5
+            + 2.69269 * hg**4 * hl
+            + 2.42843 * hg**3 * hl**2
+            + 4.47163 * hg**2 * hl**3
+            + 0.07842 * hg * hl**4
+            + hl**5
+        ) ** 0.2
+        self.assertAlmostEqual(
+            profile.GetFullProfileWidth(0.5, center, 1, 0, 0), h
+        )
+
+        x = np.array([center - h / 2, center, center + h / 2])
+        y = profile.GetProfile(x, center, 1, 0, 0)
+        np.testing.assert_allclose(y[[0, 2]] / y[1], 0.5, rtol=1e-6)
+
+        profile.SetProfilePar(hg**2)
+        self.assertAlmostEqual(
+            profile.GetFullProfileWidth(0.5, center, 1, 0, 0), hg
+        )
+        profile.SetProfilePar(0, fwhmLorentzZ=hl)
+        self.assertAlmostEqual(
+            profile.GetFullProfileWidth(0.5, center, 1, 0, 0), hl
+        )
+
+        size_width = np.deg2rad(0.03) / np.cos(center / 2)
+        profile.SetProfilePar(
+            0, fwhmScherrerP=np.deg2rad(0.03), scherrerLGmix=1
+        )
+        self.assertAlmostEqual(
+            profile.GetFullProfileWidth(0.5, center, 1, 0, 0), size_width
+        )
+        profile.SetProfilePar(
+            0, fwhmScherrerP=np.deg2rad(0.03), scherrerLGmix=0
+        )
+        self.assertAlmostEqual(
+            profile.GetFullProfileWidth(0.5, center, 1, 0, 0), size_width
+        )
+
+        self.ppd.SetProfile(profile)
+        installed = self.ppd.GetProfile()
+        self.assertIsInstance(installed, ReflectionProfilePseudoVoigtTCH)
+        self.assertAlmostEqual(
+            installed.GetPar("P").GetValue(), np.deg2rad(0.03)
+        )
+        self.assertAlmostEqual(installed.GetPar("LGmix").GetValue(), 0)
+
+        restored = ReflectionProfilePseudoVoigtTCH()
+        RefinableObj.XMLInput(restored, profile.xml())
+        self.assertAlmostEqual(
+            restored.GetPar("P").GetValue(), np.deg2rad(0.03)
+        )
+        self.assertAlmostEqual(restored.GetPar("LGmix").GetValue(), 0)
+
     def test_anisotropic_set_profile_par(self):
         """SetProfilePar assigns widths and retains symmetric default
         asymmetry."""