Re #21181. MPI support for (Find|Mask)DetectorsInShape.

Framework/DataHandling/inc/MantidDataHandling/FindDetectorsInShape.h

 #ifndef MANTID_DATAHANDLING_FINDDETECTORSINSHAPE_H_
 #define MANTID_DATAHANDLING_FINDDETECTORSINSHAPE_H_
 
-//----------------------------------------------------------------------
-// Includes
-//----------------------------------------------------------------------
-#include "MantidAPI/Algorithm.h"
+#include "MantidAPI/DistributedAlgorithm.h"
 
 namespace Mantid {
 namespace DataHandling {
@@ -55,7 +52,7 @@ namespace DataHandling {
     File change history is stored at: <https://github.com/mantidproject/mantid>.
     Code Documentation is available at: <http://doxygen.mantidproject.org>
 */
-class DLLExport FindDetectorsInShape : public API::Algorithm {
+class DLLExport FindDetectorsInShape : public API::DistributedAlgorithm {
 public:
   /// Algorithm's name for identification overriding a virtual method
   const std::string name() const override { return "FindDetectorsInShape"; };

Framework/DataHandling/inc/MantidDataHandling/MaskDetectorsInShape.h

 #ifndef MANTID_DATAHANDLING_MASKDETECTORSINSHAPE_H_
 #define MANTID_DATAHANDLING_MASKDETECTORSINSHAPE_H_
 
-//----------------------------------------------------------------------
-// Includes
-//----------------------------------------------------------------------
-#include "MantidAPI/Algorithm.h"
+#include "MantidAPI/DistributedAlgorithm.h"
 
 namespace Mantid {
 namespace DataHandling {
@@ -55,7 +52,7 @@ namespace DataHandling {
     File change history is stored at: <https://github.com/mantidproject/mantid>.
     Code Documentation is available at: <http://doxygen.mantidproject.org>
 */
-class DLLExport MaskDetectorsInShape : public API::Algorithm {
+class DLLExport MaskDetectorsInShape : public API::DistributedAlgorithm {
 public:
   /// Algorithm's name for identification overriding a virtual method
   const std::string name() const override { return "MaskDetectorsInShape"; };
@@ -79,7 +76,7 @@ private:
                                            const bool includeMonitors);
   /// Calls MaskDetectors as a Child Algorithm
   void runMaskDetectors(API::MatrixWorkspace_sptr workspace,
-                        const std::vector<int> detectorIds);
+                        const std::vector<int> &detectorIds);
 };
 
 } // namespace DataHandling

Framework/DataHandling/src/MaskDetectorsInShape.cpp

-//----------------------------------------------------------------------
-// Includes
-//----------------------------------------------------------------------
 #include "MantidDataHandling/MaskDetectorsInShape.h"
+#include "MantidDataHandling/MaskSpectra.h"
 
+#include "MantidAPI/Algorithm.tcc"
 #include "MantidAPI/MatrixWorkspace.h"
+#include "MantidGeometry/Instrument/DetectorInfo.h"
 #include "MantidKernel/ArrayProperty.h"
 #include "MantidKernel/MandatoryValidator.h"
+#include "MantidIndexing/Conversion.h"
+#include "MantidIndexing/GlobalSpectrumIndex.h"
+#include "MantidIndexing/IndexInfo.h"
 
 namespace Mantid {
 namespace DataHandling {
@@ -70,10 +73,19 @@ std::vector<int> MaskDetectorsInShape::runFindDetectorsInShape(
 }
 
 void MaskDetectorsInShape::runMaskDetectors(
-    API::MatrixWorkspace_sptr workspace, const std::vector<int> detectorIds) {
-  IAlgorithm_sptr alg = createChildAlgorithm("MaskDetectors", 0.85, 1.0);
-  alg->setProperty<std::vector<int>>("DetectorList", detectorIds);
-  alg->setProperty<MatrixWorkspace_sptr>("Workspace", workspace);
+    API::MatrixWorkspace_sptr workspace, const std::vector<int> &detectorIds) {
+  auto alg = createChildAlgorithm("MaskSpectra", 0.85, 1.0);
+  const auto &detInfo = workspace->detectorInfo();
+  std::vector<size_t> detectorIndices;
+  for (const auto id : detectorIds)
+    detectorIndices.push_back(detInfo.indexOf(id));
+  const auto &globalSpectrumIndices =
+      workspace->indexInfo().globalSpectrumIndicesFromDetectorIndices(
+          detectorIndices);
+  alg->setWorkspaceInputProperties(
+      "InputWorkspace", workspace, IndexType::WorkspaceIndex,
+      Indexing::castVector<int64_t>(globalSpectrumIndices));
+  alg->setProperty("OutputWorkspace", workspace);
   try {
     if (!alg->execute()) {
       throw std::runtime_error(

docs/source/development/AlgorithmMPISupport.rst

@@ -476,6 +476,7 @@ FilterBadPulses                   all
 FilterByLogValue                  all
 FilterByTime                      all
 FilterEventsByLogValuePreNexus    Identical               see ``IFileLoader``
+FindDetectorsInShape              all
 Fit                               MasterOnly, Identical   see ``IFittingAlgorithm``
 IFileLoader                       Identical               implicitly adds support for many load-algorithms inheriting from this
 IFittingAlgorithm                 MasterOnly, Identical   implicitly adds support for several fit-algorithms inheriting from this
@@ -526,6 +527,7 @@ LoadSwans                         Identical               see ``IFileLoader``
 LoadTBL                           Identical               see ``IFileLoader``
 LoadTOFRawNexus                   Identical               see ``IFileLoader``
 MaskBins                          all
+MaskDetectorsInShape              all
 MaskSpectra                       all
 Minus                             all                     see ``BinaryOperation``
 MoveInstrumentComponent           all