Re #21608. Getter for global vector of spectrum numbers in IndexInfo.

Framework/Indexing/inc/MantidIndexing/IndexInfo.h

@@ -96,6 +96,7 @@ public:
   size_t globalSize() const;
 
   SpectrumNumber spectrumNumber(const size_t index) const;
+  const std::vector<SpectrumNumber> &spectrumNumbers() const;
 
   void setSpectrumNumbers(std::vector<SpectrumNumber> &&spectrumNumbers);
   void setSpectrumNumbers(const SpectrumNumber min, const SpectrumNumber max);

Framework/Indexing/inc/MantidIndexing/SpectrumNumberTranslator.h

@@ -60,6 +60,7 @@ public:
   size_t localSize() const;
 
   SpectrumNumber spectrumNumber(const size_t index) const;
+  const std::vector<SpectrumNumber> &globalSpectrumNumbers() const;
 
   SpectrumIndexSet makeIndexSet() const;
   SpectrumIndexSet makeIndexSet(SpectrumNumber min, SpectrumNumber max) const;

Framework/Indexing/src/IndexInfo.cpp

@@ -109,11 +109,18 @@ size_t IndexInfo::globalSize() const {
   return m_spectrumNumberTranslator->globalSize();
 }
 
-/// Returns the spectrum number for given index.
+/// Returns the spectrum number for given *local* index, i.e., spectrum numbers
+/// for spectra in this partition.
 SpectrumNumber IndexInfo::spectrumNumber(const size_t index) const {
   return m_spectrumNumberTranslator->spectrumNumber(index);
 }
 
+/// Returns a reference to the *global* vector of spectrum numbers, i.e., the
+/// spectrum numbers of spectra across all partitions.
+const std::vector<SpectrumNumber> &IndexInfo::spectrumNumbers() const {
+  return m_spectrumNumberTranslator->globalSpectrumNumbers();
+}
+
 /// Set a spectrum number for each index.
 void IndexInfo::setSpectrumNumbers(
     std::vector<SpectrumNumber> &&spectrumNumbers) {

Framework/Indexing/src/SpectrumNumberTranslator.cpp

@@ -83,6 +83,11 @@ SpectrumNumberTranslator::SpectrumNumberTranslator(
   }
 }
 
+const std::vector<SpectrumNumber> &
+SpectrumNumberTranslator::globalSpectrumNumbers() const {
+  return m_globalSpectrumNumbers;
+}
+
 SpectrumNumberTranslator::SpectrumNumberTranslator(
     const std::vector<GlobalSpectrumIndex> &globalIndices,
     const SpectrumNumberTranslator &parent)

Framework/Indexing/test/IndexInfoTest.h

@@ -31,12 +31,14 @@ void run_StorageMode_Cloned(const Parallel::Communicator &comm) {
 void run_StorageMode_Distributed(const Parallel::Communicator &comm) {
   IndexInfo i(47, Parallel::StorageMode::Distributed, comm);
   TS_ASSERT_EQUALS(i.globalSize(), 47);
+  TS_ASSERT_EQUALS(i.spectrumNumbers().size(), 47);
   size_t expectedSize = 0;
   for (size_t globalIndex = 0; globalIndex < i.globalSize(); ++globalIndex) {
+    SpectrumNumber specNum = static_cast<int>(globalIndex) + 1;
+    TS_ASSERT_EQUALS(i.spectrumNumbers()[globalIndex], specNum);
     // Current default is RoundRobinPartitioner
     if (static_cast<int>(globalIndex) % comm.size() == comm.rank()) {
-      TS_ASSERT_EQUALS(i.spectrumNumber(expectedSize),
-                       static_cast<int>(globalIndex) + 1);
+      TS_ASSERT_EQUALS(i.spectrumNumber(expectedSize), specNum);
       ++expectedSize;
     }
   }
@@ -163,6 +165,9 @@ public:
     TS_ASSERT_EQUALS(info.spectrumNumber(0), 3);
     TS_ASSERT_EQUALS(info.spectrumNumber(1), 2);
     TS_ASSERT_EQUALS(info.spectrumNumber(2), 1);
+    TS_ASSERT_EQUALS(info.spectrumNumbers()[0], 3);
+    TS_ASSERT_EQUALS(info.spectrumNumbers()[1], 2);
+    TS_ASSERT_EQUALS(info.spectrumNumbers()[2], 1);
   }
 
   void test_construct_from_parent_reorder() {