Core fixes pointwise

CHANGELOG.md

@@ -1,5 +1,24 @@
 # Unreleased
 
+Restored the measured per-point resolution on data load (issue #368).
+
+- Loading data through `Project` (`load_new_experiment`,
+  `load_experiment_for_model_at_index`,
+  `load_all_experiments_from_file`) again sets a `Pointwise` resolution
+  function when the file carries per-point q-resolution (an sQz column
+  in `.ort` files, or a 4th column in text files). Since PR #293 the
+  loaders discarded this data and always applied a flat
+  `PercentageFwhm(5.0)` — a temporary workaround that never got
+  reverted. Fits of such data were smeared with 5% FWHM regardless of
+  what the instrument delivered and should be re-run.
+- Files without q-resolution data keep the 5% FWHM default. The pre-#293
+  fallback that built a `LinearSpline` from the _reflectivity_ error
+  (`sqrt(ye)`) was not restored: a reflectivity uncertainty is not a
+  q-width, and that branch produced effectively zero smearing.
+- Known limitation (pre-existing): the resolution function lives on the
+  model, so when several experiments share one model the last-loaded
+  dataset's resolution wins.
+
 Fixed inconsistent interpretation of vector resolution functions between
 the refnx and refl1d engines (issue #367).
 

src/easyreflectometry/project.py

@@ -28,6 +28,7 @@
 from easyreflectometry.model import Model
 from easyreflectometry.model import ModelCollection
 from easyreflectometry.model import PercentageFwhm
+from easyreflectometry.model import Pointwise
 from easyreflectometry.sample import Layer
 from easyreflectometry.sample import Material
 from easyreflectometry.sample import MaterialCollection
@@ -521,14 +522,21 @@
     ) -> None:
         """Set the resolution function on *model* based on variance data in *experiment*.
 
+        Uses the measured per-point q-resolution (``Pointwise``) when the
+        experiment carries q-variance data (``xe``, i.e. sQz²); otherwise
+        falls back to the default 5% FWHM percentage resolution.
+
         Parameters
         ----------
         experiment : DataSet1D
             The experiment whose variance data drives the choice.
         model : Model
             The model whose resolution function is set.
         """
-        model.resolution_function = PercentageFwhm(5.0)
+        if experiment.xe is not None and np.any(experiment.xe):
+            model.resolution_function = Pointwise(q_data_points=[experiment.x, experiment.y, experiment.xe])
+        else:
+            model.resolution_function = PercentageFwhm(5.0)
 
     @staticmethod
     def _auto_set_background(experiment: DataSet1D) -> None:

tests/summary/test_summary.py

@@ -136,7 +136,7 @@ def test_experiments_section(self, project: Project) -> None:
         assert 'No. of data points' in html
         assert '408' in html
         assert 'Resolution function' in html
-        assert 'PercentageFwhm' in html
+        assert 'Pointwise' in html
 
     def test_experiments_section_percentage_fhwm(self, project: Project) -> None:
         # When

tests/test_project.py

@@ -19,6 +19,7 @@
 from easyreflectometry.model import Model
 from easyreflectometry.model import ModelCollection
 from easyreflectometry.model import PercentageFwhm
+from easyreflectometry.model import Pointwise
 from easyreflectometry.project import Project
 from easyreflectometry.sample import Layer
 from easyreflectometry.sample import Material
@@ -663,7 +664,8 @@ def test_load_experiment(self):
         assert isinstance(project.experiments[5], DataSet1D)
         assert project.experiments[5].name == 'Example data file from refnx docs'
         assert project.experiments[5].model == model_5
-        assert isinstance(project.models[5].resolution_function, PercentageFwhm)
+        # example.ort carries an sQz column, so the measured resolution is used
+        assert isinstance(project.models[5].resolution_function, Pointwise)
         assert isinstance(project.models[4].resolution_function, PercentageFwhm)
 
     def test_load_experiment_sets_resolution_function_pointwise_when_xe_present(self, tmp_path):
@@ -679,12 +681,13 @@ def test_load_experiment_sets_resolution_function_pointwise_when_xe_present(self
         # Then
         project.load_experiment_for_model_at_index(str(fpath))
 
-        # Resolution is always set to PercentageFwhm
-        from easyreflectometry.model.resolution_functions import PercentageFwhm
+        # Expect Pointwise because xe (q-resolution) is present
+        resolution_function = project.models[0].resolution_function
+        assert isinstance(resolution_function, Pointwise)
+        # The 4th column is sQz (sigma); smearing() must return it unchanged
+        assert_allclose(resolution_function.smearing([0.01, 0.02]), [1e-4, 1e-4])
 
-        assert isinstance(project.models[0].resolution_function, PercentageFwhm)
-
-    def test_load_experiment_sets_linearspline_when_only_ye_present(self, tmp_path):
+    def test_load_experiment_keeps_percentage_fwhm_when_no_xe(self, tmp_path):
         # When
         global_object.map._clear()
         project = Project()
@@ -697,11 +700,45 @@ def test_load_experiment_sets_linearspline_when_only_ye_present(self, tmp_path):
         # Then
         project.load_experiment_for_model_at_index(str(fpath))
 
-        # Resolution is always set to PercentageFwhm
-        from easyreflectometry.model.resolution_functions import PercentageFwhm
-
+        # No q-resolution data available, so the 5% FWHM default is kept
         assert isinstance(project.models[0].resolution_function, PercentageFwhm)
 
+    def test_apply_resolution_function_prefers_pointwise_falls_back_to_percentage(self):
+        # When
+        global_object.map._clear()
+        project = Project()
+        model = Model()
+        with_xe = DataSet1D(x=[0.01, 0.02], y=[1.0, 2.0], ye=[0.1, 0.1], xe=[1e-8, 4e-8])
+        zero_xe = DataSet1D(x=[0.01, 0.02], y=[1.0, 2.0], ye=[0.1, 0.1], xe=[0.0, 0.0])
+        no_xe = DataSet1D(x=[0.01, 0.02], y=[1.0, 2.0], ye=[0.1, 0.1])
+
+        # Then Expect
+        project._apply_resolution_function(with_xe, model)
+        assert isinstance(model.resolution_function, Pointwise)
+        # xe holds sQz variances; smearing() must return sigma = sqrt(xe)
+        assert_allclose(model.resolution_function.smearing([0.01, 0.02]), [1e-4, 2e-4])
+
+        project._apply_resolution_function(zero_xe, model)
+        assert isinstance(model.resolution_function, PercentageFwhm)
+
+        project._apply_resolution_function(no_xe, model)
+        assert isinstance(model.resolution_function, PercentageFwhm)
+
+    def test_load_all_experiments_from_file_sets_pointwise_when_sqz_present(self):
+        # When
+        global_object.map._clear()
+        project = Project()
+        project.models = ModelCollection(Model())
+        fpath = os.path.join(PATH_STATIC, 'test_example2.ort')
+
+        # Then
+        n_loaded = project.load_all_experiments_from_file(fpath)
+
+        # Expect
+        assert n_loaded == 2
+        assert list(project.experiments.keys()) == [0, 1]
+        assert isinstance(project.models[0].resolution_function, Pointwise)
+
     def test_experimental_data_at_index(self):
         # When
         global_object.map._clear()