Add getAzimuthal calculation

Framework/DataObjects/inc/MantidDataObjects/LeanElasticPeak.h

@@ -66,7 +66,6 @@ public:
   void setInstrument(const Geometry::Instrument_const_sptr &) override;
   Geometry::IDetector_const_sptr getDetector() const override;
   Geometry::Instrument_const_sptr getInstrument() const override;
-  void setReferenceFrame(std::shared_ptr<Geometry::ReferenceFrame> frame);
   std::shared_ptr<const Geometry::ReferenceFrame>
   getReferenceFrame() const override;
 
@@ -110,6 +109,8 @@ public:
   LeanElasticPeak &operator=(const LeanElasticPeak &other);
 
 private:
+  void setReferenceFrame(std::shared_ptr<Geometry::ReferenceFrame> frame);
+
   /// Q_sample vector
   Mantid::Kernel::V3D m_Qsample;
 

Framework/DataObjects/src/LeanElasticPeak.cpp

@@ -53,7 +53,7 @@ LeanElasticPeak::LeanElasticPeak(const Mantid::Kernel::V3D &QSampleFrame)
 LeanElasticPeak::LeanElasticPeak(
     const Mantid::Kernel::V3D &QSampleFrame,
     const Mantid::Kernel::Matrix<double> &goniometer,
-    boost::optional<std::shared_ptr<ReferenceFrame>> refFrame)
+    boost::optional<std::shared_ptr<Geometry::ReferenceFrame>> refFrame)
     : BasePeak() {
   if (refFrame.is_initialized())
     setReferenceFrame(refFrame.get());
@@ -177,7 +177,15 @@ double LeanElasticPeak::getScattering() const {
 // -------------------------------------------------------------------------------------
 /** Calculate the azimuthal angle of the peak  */
 double LeanElasticPeak::getAzimuthal() const {
-  return std::numeric_limits<double>::quiet_NaN();
+  const V3D qLab = getQLabFrame();
+  std::shared_ptr<const ReferenceFrame> refFrame = getReferenceFrame();
+  const double qSign = (convention != "Crystallography") ? 1.0 : -1.0;
+  const V3D detectorDir = -qLab * qSign;
+  if (refFrame)
+    return atan2(detectorDir[refFrame->pointingUp()],
+                 detectorDir[refFrame->pointingHorizontal()]);
+  else
+    return atan2(detectorDir[1], detectorDir[0]);
 }
 
 // -------------------------------------------------------------------------------------
@@ -206,9 +214,6 @@ Mantid::Kernel::V3D LeanElasticPeak::getQSampleFrame() const {
 //----------------------------------------------------------------------------------------------
 /** Set the peak using the peak's position in reciprocal space, in the sample
  *frame.
- * The GoniometerMatrix will be used to find the Q in the lab frame, so it
- *should
- * be set beforehand.
  *
  * @param QSampleFrame :: Q of the center of the peak, in reciprocal space
  *        This is in inelastic convention: momentum transfer of the LATTICE!
@@ -239,10 +244,6 @@ void LeanElasticPeak::setQSampleFrame(
 //----------------------------------------------------------------------------------------------
 /** Set the peak using the peak's position in reciprocal space, in the lab
  *frame.
- * The detector position will be determined.
- * DetectorID, row and column will be set to -1 since they are not (necessarily)
- *found.
- * You can call findDetector to look for the detector ID
  *
  * @param qLab :: Q of the center of the peak, in reciprocal space.
  *        This is in inelastic convention: momentum transfer of the LATTICE!

Framework/DataObjects/test/LeanElasticPeakTest.h

@@ -50,7 +50,7 @@ public:
     TS_ASSERT_THROWS(p.getSamplePos(), const Exception::NotImplementedError &)
     TS_ASSERT(std::isnan(p.getTOF()))
     TS_ASSERT_EQUALS(p.getScattering(), 0.)
-    TS_ASSERT(std::isnan(p.getAzimuthal()))
+    TS_ASSERT_EQUALS(p.getAzimuthal(), -M_PI)
     TS_ASSERT_THROWS(p.getL1(), const Exception::NotImplementedError &)
     TS_ASSERT_THROWS(p.getL2(), const Exception::NotImplementedError &)
   }
@@ -90,6 +90,17 @@ public:
     TS_ASSERT_DELTA(p.getWavelength(), M_PI * 6 / 7, 1e-9)
     TS_ASSERT_DELTA(p.getDSpacing(), 1.679251908362714, 1e-9)
     TS_ASSERT_DELTA(p.getScattering(), 1.860548028230944, 1e-9)
+    TS_ASSERT_DELTA(p.getAzimuthal(), -2.6779450449, 1e-9)
+
+    // calculate Q_lab from scattering and azimuthal to check values
+    const auto k = 2 * M_PI / p.getWavelength();
+    V3D qLab(-sin(p.getScattering()) * cos(p.getAzimuthal()),
+             -sin(p.getScattering()) * sin(p.getAzimuthal()),
+             1 - cos(p.getScattering()));
+    qLab *= k;
+    TS_ASSERT_DELTA(qLab.X(), 2, 1e-9)
+    TS_ASSERT_DELTA(qLab.Y(), 1, 1e-9)
+    TS_ASSERT_DELTA(qLab.Z(), 3, 1e-9)
   }
 
   void test_Qsample_gon_constructor_refFrame() {
@@ -117,6 +128,16 @@ public:
     TS_ASSERT_DELTA(p.getWavelength(), M_PI * 4 / 7, 1e-9)
     TS_ASSERT_DELTA(p.getDSpacing(), 1.679251908362714, 1e-9)
     TS_ASSERT_DELTA(p.getScattering(), 1.1278852827212578, 1e-9)
+
+    // calculate Q_lab from scattering and azimuthal to check values
+    const auto k = 2 * M_PI / p.getWavelength();
+    V3D qLab(1 - cos(p.getScattering()),
+             -sin(p.getScattering()) * sin(p.getAzimuthal()),
+             -sin(p.getScattering()) * cos(p.getAzimuthal()));
+    qLab *= k;
+    TS_ASSERT_DELTA(qLab.X(), 2, 1e-9)
+    TS_ASSERT_DELTA(qLab.Y(), 1, 1e-9)
+    TS_ASSERT_DELTA(qLab.Z(), 3, 1e-9)
   }
 
   void test_Qsample_gon_constructor_wavelength_fail() {
@@ -294,6 +315,9 @@ public:
     TS_ASSERT_DELTA(leanpeak.getScattering(), peak.getScattering(), 1e-7);
     TS_ASSERT_DELTA(leanpeak.getScattering(), 0.2203733065, 1e-7);
 
+    TS_ASSERT_DELTA(leanpeak.getAzimuthal(), peak.getAzimuthal(), 1e-7);
+    TS_ASSERT_DELTA(leanpeak.getAzimuthal(), 0.7853981637, 1e-7);
+
     TS_ASSERT_EQUALS(leanpeak.getRunNumber(), peak.getRunNumber());
     TS_ASSERT_EQUALS(leanpeak.getRunNumber(), 1234);