Merge pull request #28800 from mantidproject/28628_HandleMaskedDetectorsInMonteCarloAbsorption

Make MonteCarloAbsorption ignore masked detectors

Framework/Algorithms/src/MonteCarloAbsorption.cpp

@@ -273,8 +273,8 @@ MatrixWorkspace_uptr MonteCarloAbsorption::doSimulation(
     auto &outE = simulationWS.mutableE(i);
     // The input was cloned so clear the errors out
     outE = 0.0;
-    // Final detector position
-    if (!spectrumInfo.hasDetectors(i)) {
+
+    if (!spectrumInfo.hasDetectors(i) || spectrumInfo.isMasked(i)) {
       continue;
     }
     // Per spectrum values

Framework/Algorithms/test/MonteCarloAbsorptionTest.h

@@ -10,6 +10,7 @@
 #include "MantidAPI/FileFinder.h"
 #include "MantidAPI/FrameworkManager.h"
 #include "MantidAPI/Sample.h"
+#include "MantidAPI/SpectrumInfo.h"
 #include "MantidAlgorithms/ConvertUnits.h"
 #include "MantidAlgorithms/MonteCarloAbsorption.h"
 #include "MantidDataHandling/LoadBinaryStl.h"
@@ -282,6 +283,26 @@ public:
     TS_ASSERT_THROWS_NOTHING(mcAbsorb->execute());
   }
 
+  void test_ignore_masked_spectra() {
+    using Mantid::Kernel::DeltaEMode;
+    TestWorkspaceDescriptor wsProps = {
+        5, 10, Environment::SampleOnly, DeltaEMode::Elastic, -1, -1};
+    auto testWS = setUpWS(wsProps);
+    testWS->mutableSpectrumInfo().setMasked(0, true);
+    auto mcAbsorb = createAlgorithm();
+    TS_ASSERT_THROWS_NOTHING(mcAbsorb->setProperty("InputWorkspace", testWS));
+    TS_ASSERT_THROWS_NOTHING(mcAbsorb->execute());
+    auto outputWS = getOutputWorkspace(mcAbsorb);
+    // should still output a spectra but it should also be masked and equal to
+    // zero
+    TS_ASSERT_EQUALS(outputWS->getNumberHistograms(), 5);
+    TS_ASSERT_EQUALS(outputWS->spectrumInfo().isMasked(0), true);
+    auto yData = outputWS->getSpectrum(0).dataY();
+    bool allZero = std::all_of(yData.begin(), yData.end(),
+                               [](double i) { return i == 0; });
+    TS_ASSERT_EQUALS(allZero, true);
+  }
+
   //---------------------------------------------------------------------------
   // Failure cases
   //---------------------------------------------------------------------------

docs/source/release/v5.1.0/framework.rst

@@ -20,6 +20,7 @@ Algorithms
    cost of cloning the inputWorkspace.
 - Adjusted :ref:`AddPeak <algm-AddPeak>` to only allow peaks from the same instrument as the peaks worksapce to be added to that workspace.
 - :ref:`MonteCarloAbsorption <algm-MonteCarloAbsorption>` Bug fixed where setting ResimulateTracksForDifferentWavelengths parameter to True was being ignored
+- :ref:`MonteCarloAbsorption <algm-MonteCarloAbsorption>` Corrections are not calculated anymore for masked spectra
 - :ref:`MaskDetectorsIf <algm-MaskDetectorsIf>` has received a number of updates:
 
   - The algorithm now checks all of the data bins for each spectrum of a workspace, previously it only checked the first bin.