Merge pull request #22337 from mantidproject/21967_ConvertToDistribution

Convert the workspace into distribution in DirectILLReduction

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

@@ -6,8 +6,9 @@ import DirectILL_common as common
 from mantid.api import (AlgorithmFactory, DataProcessorAlgorithm, InstrumentValidator,
                         MatrixWorkspaceProperty, Progress, PropertyMode, WorkspaceProperty, WorkspaceUnitValidator)
 from mantid.kernel import (CompositeValidator, Direction, FloatArrayProperty, StringListValidator)
-from mantid.simpleapi import (BinWidthAtX, CloneWorkspace, ConvertSpectrumAxis, ConvertUnits, CorrectKiKf, DetectorEfficiencyCorUser,
-                              Divide, GroupDetectors, MaskDetectors, Rebin, Scale, SofQWNormalisedPolygon, Transpose)
+from mantid.simpleapi import (BinWidthAtX, CloneWorkspace, ConvertSpectrumAxis, ConvertToDistribution, ConvertUnits, CorrectKiKf,
+                              DetectorEfficiencyCorUser, Divide, GroupDetectors, MaskDetectors, Rebin, Scale, SofQWNormalisedPolygon,
+                              Transpose)
 import math
 import numpy
 import roundinghelper
@@ -225,6 +226,9 @@ class DirectILLReduction(DataProcessorAlgorithm):
         mainWS = self._rebinInW(mainWS, wsNames, wsCleanup, report,
                                 subalgLogging)
 
+        # Divide the energy transfer workspace by bin widths.
+        mainWS = self._convertToDistribution(mainWS, wsNames, wsCleanup, subalgLogging)
+
         # Detector efficiency correction.
         progress.report('Correcting detector efficiency')
         mainWS = self._correctByDetectorEfficiency(mainWS, wsNames,
@@ -340,6 +344,17 @@ class DirectILLReduction(DataProcessorAlgorithm):
         wsCleanup.cleanup(mainWS)
         return maskedWS
 
+    def _convertToDistribution(self, mainWS, wsNames, wsCleanup, subalgLogging):
+        """Convert the workspace into a distribution."""
+        distributionWSName = wsNames.withSuffix('as_distribution')
+        distributionWS = CloneWorkspace(InputWorkspace=mainWS,
+                                        OutputWorkspace=distributionWSName,
+                                        EnableLogging=subalgLogging)
+        wsCleanup.cleanup(mainWS)
+        ConvertToDistribution(Workspace=distributionWS,
+                              EnableLogging=subalgLogging)
+        return distributionWS
+
     def _convertTOFToDeltaE(self, mainWS, wsNames, wsCleanup, subalgLogging):
         """Convert the X axis units from time-of-flight to energy transfer."""
         energyConvertedWSName = wsNames.withSuffix('energy_converted')

Framework/PythonInterface/test/python/plugins/algorithms/WorkflowAlgorithms/DirectILLReductionTest.py

@@ -78,6 +78,22 @@ class DirectILLReductionTest(unittest.TestCase):
         groupIds = groupedWS.getDetector(0).getDetectorIDs()
         self.assertEqual(collections.Counter(detectorIds), collections.Counter(groupIds))
 
+    def testOutputIsDistribution(self):
+        outWSName = 'outWS'
+        algProperties = {
+            'InputWorkspace': self._TEST_WS_NAME,
+            'OutputWorkspace': outWSName,
+            'OutputSofThetaEnergyWorkspace': 'SofThetaE',
+            'rethrow': True
+        }
+        run_algorithm('DirectILLReduction', **algProperties)
+        self.assertTrue(mtd.doesExist(outWSName))
+        ws = mtd[outWSName]
+        self.assertTrue(ws.isDistribution())
+        self.assertTrue(mtd.doesExist('SofThetaE'))
+        ws = mtd['SofThetaE']
+        self.assertTrue(ws.isDistribution())
+
     def _checkAlgorithmsInHistory(self, ws, *args):
         """Return true if algorithm names listed in *args are found in the
         workspace's history.

docs/source/diagrams/DirectILLReduction-v1_wkflw.dot

@@ -23,6 +23,7 @@ digraph DirectILLReduction {
     $algorithm_style
     AbsoluteUnits [label="Scale to absolute units"]
     ApplyDiagnostics [label="Mask spectra"]
+    ConvertToDistribution [label="ConvertToDistribution"]
     ConvertToEnergy [label="Convert TOF to energy transfer"]
     CorrectKiKf [label="CorrectKiKf"]
     DetectorEfficiency [label="DetectorEfficiencyCorUser"]
@@ -49,7 +50,8 @@ digraph DirectILLReduction {
   ConvertToEnergy -> CorrectKiKf
   CorrectKiKf -> Rebin
   wRebinParams -> Rebin
-  Rebin -> DetectorEfficiency
+  Rebin -> ConvertToDistribution
+  ConvertToDistribution -> DetectorEfficiency
   DetectorEfficiency -> GroupDetectors
   GroupDetectors -> outputOptionalWS
   GroupDetectors -> SofQW

docs/source/release/v3.13.0/direct_inelastic.rst

@@ -20,6 +20,8 @@ New features
 Improvements
 ############
 
+- :ref:`DirectILLReduction <algm-DirectILLReduction>` now converts all its output workspaces to distributions, i.e. divides the histograms by the bin width.
+
 Bug fixes
 #########