Merge pull request #24526 from mantidproject/21401_IndirectElasticWindowMultiplePropagateErrors

Indirect - ElasticWindowMultiple doesn't propagate errors

Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/ElasticWindowMultiple.py

@@ -10,6 +10,8 @@ from mantid.simpleapi import AppendSpectra, CloneWorkspace, ElasticWindow, LoadL
 from mantid.kernel import *
 from mantid.api import *
 
+import numpy as np
+
 
 def _normalize_by_index(workspace, index):
     """
@@ -19,15 +21,28 @@ def _normalize_by_index(workspace, index):
     @param workspace    The workspace to normalize.
     @param index        The index of the y-value to normalize by.
     """
+    number_of_histograms = workspace.getNumberHistograms()
+
+    for idx in range(0, number_of_histograms):
+        y_values = workspace.readY(idx)
+        y_errors = workspace.readE(idx)
+
+        # Avoid divide by zero
+        if y_values[index] == 0.0:
+            scale = np.reciprocal(1.0e-8)
+        else:
+            scale = np.reciprocal(y_values[index])
+
+        # Normalise y values
+        y_values_normalised = scale * y_values
 
-    num_hist = workspace.getNumberHistograms()
+        # Propagate y errors: C = A / B ; dC = sqrt( (dA/B)^2 + (A*dB/B^2)^2 )
+        a = (y_errors*scale)
+        b = (y_values*y_errors[index]*(scale ** 2))
+        y_errors_propagated = np.sqrt(a ** 2 + b ** 2)
 
-    # Normalize each spectrum in the workspace
-    for idx in range(0, num_hist):
-        y_vals = workspace.readY(idx)
-        scale = 1.0 / y_vals[index]
-        y_vals_scaled = scale * y_vals
-        workspace.setY(idx, y_vals_scaled)
+        workspace.setY(idx, y_values_normalised)
+        workspace.setE(idx, y_errors_propagated)
 
 
 class ElasticWindowMultiple(DataProcessorAlgorithm):

Testing/SystemTests/tests/analysis/reference/II.AnalysisElWinMulti.nxs.md5

-c411c711cfef6fea15184c45d733a480
+bd3274a0fe71c8d634f7cecd4d90479e
\ No newline at end of file

docs/source/release/v3.14.0/indirect_inelastic.rst

@@ -75,6 +75,7 @@ Bugfixes
 - The output workspace ending with _Results now contains workspaces with corrected names which detail the fit functions used.
 - Selecting multiple data using the All Spectra checkbox without first selected a sample file used to cause an unexpected error.
   This is now prevented. Meaningful error messages are also displayed when a sample or resolution file are not selected.
+- In the Elwin interface, the errors are now propagated correctly through to the workspace with extension _elt.
 
 
 Data Corrections Interface

qt/scientific_interfaces/Indirect/Elwin.cpp

@@ -325,7 +325,7 @@ void Elwin::setPlotSpectrumValue(int value) {
 }
 
 void Elwin::updateAvailablePlotSpectra() {
-  auto const name = m_uiForm.cbPlotWorkspace->currentText().toStdString();
+  auto const name = getPlotWorkspaceName().toStdString();
   auto const maximumValue = getNumberOfSpectra(name) - 1;
   setPlotSpectrumMinMax(0, maximumValue);
   setPlotSpectrumValue(0);

qt/scientific_interfaces/Indirect/Elwin.ui

@@ -314,6 +314,9 @@
              <height>0</height>
             </size>
            </property>
+           <property name="sizeAdjustPolicy">
+            <enum>QComboBox::AdjustToContents</enum>
+           </property>
           </widget>
          </item>
          <item>

qt/scientific_interfaces/Indirect/Stretch.ui

@@ -365,6 +365,9 @@
                <height>0</height>
               </size>
              </property>
+             <property name="sizeAdjustPolicy">
+              <enum>QComboBox::AdjustToContents</enum>
+             </property>
             </widget>
            </item>
            <item>
@@ -411,17 +414,17 @@
   </layout>
  </widget>
  <customwidgets>
-  <customwidget>
-   <class>MantidQt::MantidWidgets::DataSelector</class>
-   <extends>QWidget</extends>
-   <header>MantidQtWidgets/Common/DataSelector.h</header>
-  </customwidget>
   <customwidget>
    <class>MantidQt::MantidWidgets::PreviewPlot</class>
    <extends>QWidget</extends>
    <header>MantidQtWidgets/LegacyQwt/PreviewPlot.h</header>
    <container>1</container>
   </customwidget>
+  <customwidget>
+   <class>MantidQt::MantidWidgets::DataSelector</class>
+   <extends>QWidget</extends>
+   <header>MantidQtWidgets/Common/DataSelector.h</header>
+  </customwidget>
  </customwidgets>
  <resources/>
  <connections/>