Consolidate code relating to Q convention.

Refs #26839

Framework/Crystal/inc/MantidCrystal/PeakAlgorithmHelpers.h

@@ -14,6 +14,12 @@ class V3D;
 
 namespace Mantid::Crystal {
 
+/// return -1 if convention is "Crystallography" and 1 otherwise.
+double qConventionFactor(const std::string &convention);
+
+/// convenience overload to pull the convention from the config service
+double qConventionFactor();
+
 /// Tie together a modulated peak number with its offset
 using MNPOffset = std::tuple<double, double, double, Kernel::V3D>;
 

Framework/Crystal/src/PeakAlgorithmHelpers.cpp

@@ -8,16 +8,35 @@
 #include "MantidKernel/ArrayLengthValidator.h"
 #include "MantidKernel/ArrayProperty.h"
 #include "MantidKernel/BoundedValidator.h"
+#include "MantidKernel/ConfigService.h"
 #include "MantidKernel/V3D.h"
 
 using Mantid::Kernel::ArrayLengthValidator;
 using Mantid::Kernel::ArrayProperty;
 using Mantid::Kernel::BoundedValidator;
+using Mantid::Kernel::ConfigService;
 using Mantid::Kernel::Direction;
 using Mantid::Kernel::V3D;
 
 namespace Mantid::Crystal {
 
+/**
+ * @return -1 if Q.convention==Crystallography, else return 1.0
+ */
+double qConventionFactor(const std::string &convention) {
+  if (convention == "Crystallography") {
+    return -1.0;
+  }
+  return 1.0;
+}
+
+/**
+ * @return qConventionFactor for Q.convention setting in ConfigService
+ */
+double qConventionFactor() {
+  return qConventionFactor(ConfigService::Instance().getString("Q.convention"));
+}
+
 /**
  * Append the common set of properties that relate to modulation vectors
  * to the given algorithm

Framework/Crystal/src/PredictPeaks.cpp

@@ -9,6 +9,7 @@
 #include "MantidAPI/MatrixWorkspace.h"
 #include "MantidAPI/Run.h"
 #include "MantidAPI/Sample.h"
+#include "MantidCrystal/PeakAlgorithmHelpers.h"
 #include "MantidGeometry/Crystal/BasicHKLFilters.h"
 #include "MantidGeometry/Crystal/EdgePixel.h"
 #include "MantidGeometry/Crystal/HKLFilterWavelength.h"
@@ -38,24 +39,11 @@ using namespace Mantid::DataObjects;
 using namespace Mantid::Geometry;
 using namespace Mantid::Kernel;
 
-namespace {
-/// Small helper function that return -1 if convention
-/// is "Crystallography" and 1 otherwise.
-double get_factor_for_q_convention(const std::string &convention) {
-  if (convention == "Crystallography") {
-    return -1.0;
-  }
-
-  return 1.0;
-}
-} // namespace
-
 /** Constructor
  */
 PredictPeaks::PredictPeaks()
     : m_runNumber(-1), m_inst(), m_pw(), m_sfCalculator(),
-      m_qConventionFactor(get_factor_for_q_convention(
-          ConfigService::Instance().getString("Q.convention"))) {
+      m_qConventionFactor(qConventionFactor()) {
   m_refConds = getAllReflectionConditions();
 }
 
@@ -510,7 +498,7 @@ void PredictPeaks::fillPossibleHKLsUsingPeaksWorkspace(
    * for the convention stored in the workspace.
    */
   double peaks_q_convention_factor =
-      get_factor_for_q_convention(peaksWorkspace->getConvention());
+      qConventionFactor(peaksWorkspace->getConvention());
 
   for (int i = 0; i < static_cast<int>(peaksWorkspace->getNumberPeaks()); ++i) {
     IPeak &p = peaksWorkspace->getPeak(i);

Framework/Crystal/src/PredictSatellitePeaks.cpp

@@ -9,6 +9,7 @@
 #include "MantidAPI/Run.h"
 #include "MantidAPI/Sample.h"
 #include "MantidAPI/WorkspaceFactory.h"
+#include "MantidCrystal/PeakAlgorithmHelpers.h"
 #include "MantidDataObjects/PeaksWorkspace.h"
 #include "MantidGeometry/Crystal/BasicHKLFilters.h"
 #include "MantidGeometry/Crystal/HKLGenerator.h"
@@ -30,23 +31,11 @@ namespace Crystal {
 
 DECLARE_ALGORITHM(PredictSatellitePeaks)
 
-namespace {
-/// Small helper function that return -1 if convention
-/// is "Crystallography" and 1 otherwise.
-double get_factor_for_q_convention(const std::string &convention) {
-  if (convention == "Crystallography") {
-    return -1.0;
-  }
-  return 1.0;
-}
-} // namespace
-
 /** Constructor
  */
 
 PredictSatellitePeaks::PredictSatellitePeaks()
-    : m_qConventionFactor(get_factor_for_q_convention(
-          ConfigService::Instance().getString("Q.convention"))) {}
+    : m_qConventionFactor(qConventionFactor()) {}
 
 /// Initialise the properties
 void PredictSatellitePeaks::init() {