refs #11056. Peak looks up detector after setQLab.

Refactor to use the ray tracing tools to look up the detector. Distance is optional, but I'd rather remove it altogether.

Code/Mantid/Framework/API/inc/MantidAPI/IPeak.h

@@ -7,6 +7,7 @@
 #include "MantidKernel/Matrix.h"
 #include "MantidKernel/V3D.h"
 #include "MantidKernel/PhysicalConstants.h"
+#include <boost/optional.hpp>
 
 namespace Mantid {
 namespace API {
@@ -52,7 +53,7 @@ public:
   virtual void setQSampleFrame(Mantid::Kernel::V3D QSampleFrame,
                                double detectorDistance = 1.0) = 0;
   virtual void setQLabFrame(Mantid::Kernel::V3D QLabFrame,
-                            double detectorDistance = 1.0) = 0;
+                            boost::optional<double> detectorDistance = boost::optional<double>()) = 0;
 
   virtual void setWavelength(double wavelength) = 0;
   virtual double getWavelength() const = 0;

Code/Mantid/Framework/DataObjects/inc/MantidDataObjects/Peak.h

@@ -3,12 +3,15 @@
 
 #include "MantidAPI/IPeak.h"
 #include "MantidGeometry/Instrument.h"
+#include "MantidKernel/Logger.h"
 #include "MantidKernel/Matrix.h"
 #include "MantidKernel/V3D.h"
 #include "MantidKernel/PhysicalConstants.h"
 #include "MantidKernel/System.h"
 #include "MantidGeometry/Crystal/PeakShape.h"
 #include <boost/shared_ptr.hpp>
+#include <boost/optional.hpp>
+
 
 namespace Mantid {
 namespace DataObjects {
@@ -85,7 +88,7 @@ public:
   void setQSampleFrame(Mantid::Kernel::V3D QSampleFrame,
                        double detectorDistance = 1.0);
   void setQLabFrame(Mantid::Kernel::V3D QLabFrame,
-                    double detectorDistance = 1.0);
+                    boost::optional<double> detectorDistance = boost::optional<double>());
 
   void setWavelength(double wavelength);
   double getWavelength() const;
@@ -134,7 +137,7 @@ public:
 
 private:
 
-
+  bool findDetector(const Mantid::Kernel::V3D &beam);
 
   /// Shared pointer to the instrument (for calculating some values )
   Geometry::Instrument_const_sptr m_inst;
@@ -208,6 +211,9 @@ private:
 
   /// Peak shape
   Mantid::Geometry::PeakShape_const_sptr m_peakShape;
+
+  /// Static logger
+  static Mantid::Kernel::Logger g_log;
 };
 
 } // namespace Mantid

Code/Mantid/Framework/DataObjects/src/Peak.cpp

@@ -484,11 +484,11 @@ void Peak::setQSampleFrame(Mantid::Kernel::V3D QSampleFrame,
  *        This is in inelastic convention: momentum transfer of the LATTICE!
  *        Also, q does have a 2pi factor = it is equal to 2pi/wavelength (in
  *Angstroms).
- * @param detectorDistance :: distance between the sample and the detector.
- *        Used to give a valid TOF. Default 1.0 meters.
+ * @param detectorDistance :: distance between the sample and the detector. If this is provided. Then we do not
+ * ray trace to find the intersecing detector.
  */
 void Peak::setQLabFrame(Mantid::Kernel::V3D QLabFrame,
-                        double detectorDistance) {
+                        boost::optional<double> detectorDistance) {
   // Clear out the detector = we can't know them
   m_DetectorID = -1;
   m_det = IDetector_sptr();
@@ -535,11 +535,25 @@ void Peak::setQLabFrame(Mantid::Kernel::V3D QLabFrame,
   this->setWavelength(wl);
 
   V3D detectorDir = q * -1.0;
-  detectorDir[refFrame->pointingAlongBeam()] = one_over_wl - q.Z();
+  detectorDir[refFrame->pointingAlongBeam()] = one_over_wl - qBeam;
   detectorDir.normalize();
 
   // Use the given detector distance to find the detector position.
-  detPos = samplePos + detectorDir * detectorDistance;
+  if(detectorDistance.is_initialized())
+  {
+      detPos = samplePos + detectorDir * detectorDistance.get();
+      // We do not-update the detector as by manually setting the distance the client seems to know better.
+  }
+  else
+  {
+      // Find the detector
+      const bool found = findDetector(detectorDir);
+      if (!found)
+      {
+          // This is important, so we ought to log when this fails to happen.
+          g_log.debug("Could not find detector after setting qLab via setQLab with QLab : " + q.toString());
+      }
+  }
 }
 
 /** After creating a peak using the Q in the lab frame,
@@ -552,12 +566,22 @@ void Peak::setQLabFrame(Mantid::Kernel::V3D QLabFrame,
  * @return true if the detector ID was found.
  */
 bool Peak::findDetector() {
-  bool found = false;
+
   // Scattered beam direction
   V3D oldDetPos = detPos;
   V3D beam = detPos - samplePos;
   beam.normalize();
 
+  return findDetector(beam);
+}
+
+/**
+ * @brief Peak::findDetector : Find the detector along the beam location. sets the detector, and detector position if found
+ * @param beam : detector direction from the sample as V3D
+ * @return True if a detector has been found
+ */
+bool Peak::findDetector(const Mantid::Kernel::V3D &beam) {
+    bool found = false;
   // Create a ray tracer
   InstrumentRayTracer tracker(m_inst);
   tracker.traceFromSample(beam);
@@ -904,5 +928,7 @@ Mantid::Kernel::V3D Peak::getDetectorPosition() const {
   return getDetector()->getPos();
 }
 
+Mantid::Kernel::Logger Peak::g_log("PeakLogger");
+
 } // namespace Mantid
 } // namespace DataObjects

Code/Mantid/Framework/DataObjects/test/PeakTest.h

@@ -329,7 +329,7 @@ public:
       const double l1 = beam1.norm();
       const double l2 = beam2.norm();
       const double scatteringAngle2 = beam2.angle(beam1);
-      const V3D qLabDir = beam1 - beam2;
+      const V3D qLabDir = (beam1/l1) - (beam2/l2);
 
       // Derive the wavelength
       std::vector<double> x;
@@ -427,7 +427,7 @@ public:
     const double wavelength = 2;
     Peak p(inst, detectorId, wavelength);
     TSM_ASSERT_THROWS_NOTHING("Nothing wrong here, detector is valid", p.getDetectorPosition());
-    p.setQLabFrame(V3D(1,1,1), 1); // This sets the detector pointer to null and detector id to -1;
+    p.setQLabFrame(V3D(1,1,1), 1.0); // This sets the detector pointer to null and detector id to -1;
     TSM_ASSERT_THROWS("Detector is not valid", p.getDetectorPosition(), Mantid::Kernel::Exception::NullPointerException&);
   }
 

Code/Mantid/Framework/TestHelpers/src/ComponentCreationHelper.cpp

@@ -582,18 +582,21 @@ Instrument_sptr createMinimalInstrument(const V3D& sourcePos, const V3D& sampleP
     // A source
     ObjComponent *source = new ObjComponent("source");
     source->setPos(sourcePos);
+    source->setShape(createSphere(0.01 /*1cm*/, V3D(0,0,0), "1"));
     instrument->add(source);
     instrument->markAsSource(source);
 
     // A sample
     ObjComponent *sample = new ObjComponent("some-surface-holder");
-    source->setPos(samplePos);
+    sample->setPos(samplePos);
+    sample->setShape(createSphere(0.01 /*1cm*/, V3D(0,0,0), "1"));
     instrument->add(sample);
     instrument->markAsSamplePos(sample);
 
     // A detector
     Detector *det = new Detector("point-detector", 1 /*detector id*/, NULL);
     det->setPos(detectorPos);
+    det->setShape(createSphere(0.01 /*1cm*/, V3D(0,0,0), "1"));
     instrument->add(det);
     instrument->markAsDetector(det);