Skip reflectivity calculation for direct beams (#115)

* skip calculating the reflectivity of runs whose metadata categorize them as direct beam

docs/releasenotes/index.rst

@@ -12,6 +12,7 @@ Notes for major and minor releases. Notes for Patch releases are deferred.
 
 **Of interest to the User**:
 
+- PR #115: Skip reflectivity calculation for direct beams
 - PR #104: Update Mantid version to 6.10
 - PR #95: Optional dead-time correction (disabled by default)
 - PR #91: Add ability to reduce multiple samples from the same run

reflectivity_ui/interfaces/data_handling/data_set.py

@@ -462,6 +462,10 @@ def load(self, update_parameters=True, progress=None):
 
         return self.cross_sections
 
+    def is_direct_beam(self):
+        """Returns True if the main cross-section is a direct beam"""
+        return self.cross_sections[self.main_cross_section].is_direct_beam
+
 
 class CrossSectionData(object):
     """

reflectivity_ui/interfaces/data_manager.py

@@ -475,10 +475,11 @@ def load(self, file_path, configuration, force=False, update_parameters=True, pr
                     self.direct_beam_list[direct_beam_list_id] = nexus_data
 
                 # Compute reflectivity
-                try:
-                    self.calculate_reflectivity()
-                except Exception as e:
-                    logging.error("Reflectivity calculation failed for %s exception %s", file_name, e)
+                if not nexus_data.is_direct_beam():
+                    try:
+                        self.calculate_reflectivity()
+                    except Exception as e:
+                        logging.error("Reflectivity calculation failed for %s exception %s", file_name, e)
 
                 # if cached reduced data exceeds maximum cache size, remove the oldest reduced data
                 while len(self._cache) >= self.MAX_CACHE:

test/ui/test_missing_cross_section.py

@@ -24,11 +24,9 @@ def test_missing_cross_section(qtbot):
     intensity_off_on = np.sum(ui_utilities.data_from_plot2D(main_window.xtof_overview))
     # select the On-On spin combination
     main_window.selectedChannel1.click()
-    # check that the reflectivity curve is empty
-    _, data_y = ui_utilities.data_from_plot1D(main_window.refl)
-    test = data_y.data - data_y.data[0]
-    assert np.all(test <= TEST_REFLECTIVITY_THRESHOLD_VALUE)
-    tmp = ui_utilities.data_from_plot2D(main_window.xtof_overview)
+    # check that no reflectivity curve is displayed
+    plot_text = ui_utilities.text_from_plot1D(main_window.refl)
+    assert plot_text == "No data"
     # check the x vs TOF plot has changed
     intensity_on_on = np.sum(ui_utilities.data_from_plot2D(main_window.xtof_overview))
     assert intensity_on_on / intensity_off_on < TEST_REFLECTIVITY_THRESHOLD_VALUE

test/ui/ui_utilities.py

@@ -2,6 +2,7 @@
 
 
 # third party imports
+import matplotlib.pyplot as plt
 from numpy.ma import MaskedArray
 from PyQt5 import QtCore
 
@@ -47,6 +48,23 @@ def data_from_plot2D(widget: "MplWidget") -> MaskedArray:
     return axes.get_images()[0].get_array()
 
 
+def text_from_plot1D(widget: "MplWidget", line_number=0) -> tuple:
+    r"""Get the text from an MplWidget representing a 1D plot
+    Returns
+    -------
+    str
+        The first text that is not a title or label
+    """
+    figure = widget.canvas.fig
+    axes = figure.get_axes()[0]
+    texts = [
+        child
+        for child in axes.get_children()
+        if isinstance(child, plt.Text) and child not in [axes.title, axes.xaxis.label, axes.yaxis.label]
+    ]
+    return texts[0].get_text()
+
+
 def set_current_file_by_run_number(widget, run_number):
     r"""Set the selected file in the main window file list by the given run number"""
     list_item = widget.file_list.findItems(str(run_number), QtCore.Qt.MatchContains)[0]