Refs #5285 MatrixWorkspace-level generateHistogram() method

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

@@ -231,7 +231,8 @@ namespace Mantid
       virtual void setData(const std::size_t index, const MantidVecPtr::ptr_type& Y, const MantidVecPtr::ptr_type& E)
       { getSpectrum(index)->setData(Y,E); }
 
-
+      /// Generate the histogram or rebin the existing histogram.
+      virtual void generateHistogram(const std::size_t index, const MantidVec& X, MantidVec& Y, MantidVec& E, bool skipError = false) const = 0;
 
 
       /// Return a vector with the integrated counts for all spectra withing the given range

Code/Mantid/Framework/API/test/CompositeFunctionTest.h

@@ -73,6 +73,8 @@ class CompositeFunctionTest_MocMatrixWorkspace : public MatrixWorkspace
   virtual const ISpectrum * getSpectrum(const size_t index) const {return &m_spectra[index];}
   const std::string id(void) const {return "";}
   void init(const size_t &,const size_t &,const size_t &) { }
+  void generateHistogram(const std::size_t , const MantidVec& , MantidVec& , MantidVec& , bool ) const { }
+
 private:
   std::vector<CompositeFunctionTest_MocSpectrum> m_spectra;
   size_t m_blocksize;

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

@@ -125,6 +125,8 @@ class DLLExport EventWorkspace : public API::IEventWorkspace
   // Get a pointer to the x data at the given workspace index
   Kernel::cow_ptr<MantidVec> refX(const std::size_t) const;
 
+  void generateHistogram(const std::size_t index, const MantidVec& X, MantidVec& Y, MantidVec& E, bool skipError = false) const;
+
   //------------------------------------------------------------
   // Set the x-axis data (histogram bins) for all pixels
   void setAllX(Kernel::cow_ptr<MantidVec> &x);

Code/Mantid/Framework/DataObjects/inc/MantidDataObjects/Workspace2D.h

@@ -80,6 +80,7 @@ class DLLExport Workspace2D : public API::MatrixWorkspace
   /// Return the underlying ISpectrum ptr (const version) at the given workspace index.
   virtual const Mantid::API::ISpectrum * getSpectrum(const size_t index) const;
 
+  void generateHistogram(const std::size_t index, const MantidVec& X, MantidVec& Y, MantidVec& E, bool skipError = false) const;
 
   /** sets the monitorWorkspace indexlist
     @param mList :: a vector holding the monitor workspace indexes

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

@@ -79,6 +79,7 @@ class DLLExport WorkspaceSingleValue : public API::MatrixWorkspace
   // Return the underlying ISpectrum ptr (const version) at the given workspace index.
   virtual const Mantid::API::ISpectrum * getSpectrum(const size_t index) const;
 
+  void generateHistogram(const std::size_t index, const MantidVec& X, MantidVec& Y, MantidVec& E, bool skipError = false) const;
 
 private:
   /// Private copy constructor. NO COPY ALLOWED

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

@@ -703,6 +703,22 @@ namespace DataObjects
     return this->data[index]->ptrX();
   }
 
+  //---------------------------------------------------------------------------
+  /** Using the event data in the event list, generate a histogram of it.
+   *
+   * @param index :: workspace index to generate
+   * @param X :: input X vector of the bin boundaries.
+   * @param Y :: output vector to be filled with the Y data.
+   * @param E :: output vector to be filled with the Error data (optionally)
+   * @param skipError :: if true, the error vector is NOT calculated.
+   *        This may save some processing time.
+   */
+   void EventWorkspace::generateHistogram(const std::size_t index, const MantidVec& X, MantidVec& Y, MantidVec& E, bool skipError) const
+  {
+    if (index >= this->m_noVectors)
+      throw std::range_error("EventWorkspace::generateHistogram, histogram number out of range");
+    this->data[index]->generateHistogram(X, Y, E, skipError);
+  }
 
 
   //-----------------------------------------------------------------------------

Code/Mantid/Framework/DataObjects/src/Workspace2D.cpp

@@ -8,6 +8,7 @@
 #include "MantidAPI/WorkspaceProperty.h"
 #include "MantidAPI/WorkspaceFactory.h"
 #include "MantidAPI/ISpectrum.h"
+#include "MantidKernel/VectorHelper.h"
 
 using Mantid::API::ISpectrum;
 
@@ -121,6 +122,36 @@ namespace Mantid
       return data.size();
     }
 
+
+    //---------------------------------------------------------------------------
+    /** Rebin a particulare spectrum to a new histogram bin boundaries.
+     *
+     * @param index :: workspace index to generate
+     * @param X :: input X vector of the bin boundaries.
+     * @param Y :: output vector to be filled with the Y data.
+     * @param E :: output vector to be filled with the Error data (optionally)
+     * @param skipError :: if true, the error vector is NOT calculated.
+     *        CURRENTLY IGNORED, the Error is always calculated.
+     */
+    void Workspace2D::generateHistogram(const std::size_t index, const MantidVec& X, MantidVec& Y, MantidVec& E, bool skipError) const
+    {
+      UNUSED_ARG(skipError);
+      if (index >= this->m_noVectors)
+        throw std::range_error("Workspace2D::generateHistogram, histogram number out of range");
+      // output data arrays are implicitly filled by function
+      const ISpectrum * spec = this->getSpectrum(index);
+      const MantidVec & currentX = spec->readX();
+      const MantidVec & currentY = spec->readY();
+      const MantidVec & currentE = spec->readE();
+      if (X.size() <= 1) throw std::runtime_error("Workspace2D::generateHistogram(): X vector must be at least length 2");
+      Y.resize(X.size()-1, 0);
+      E.resize(X.size()-1, 0);
+      // Perform the rebin from the current bins to the new ones
+      Mantid::Kernel::VectorHelper::rebin(currentX,currentY,currentE, X, Y, E,
+          this->isDistribution());
+    }
+
+
   } // namespace DataObjects
 } //NamespaceMantid
 

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

@@ -57,6 +57,17 @@ namespace Mantid
       return &data;
     }
 
+    /// Rebin the workspace. Not implemented for this workspace.
+    void WorkspaceSingleValue::generateHistogram(const std::size_t index, const MantidVec& X, MantidVec& Y, MantidVec& E, bool skipError) const
+    {
+      UNUSED_ARG(index);
+      UNUSED_ARG(X);
+      UNUSED_ARG(Y);
+      UNUSED_ARG(E);
+      UNUSED_ARG(skipError);
+      throw std::runtime_error("generateHistogram() not implemented for WorkspaceSingleValue.");
+    }
+
 
   } // namespace DataObjects
 } // namespace Mantid

Code/Mantid/Framework/DataObjects/test/Workspace2DTest.h

@@ -166,6 +166,23 @@ class Workspace2DTest : public CxxTest::TestSuite
     }
   }
 
+  void test_generateHistogram()
+  {
+    Workspace2D_sptr ws = Create2DWorkspaceBinned(2, 5);
+    MantidVec X, Y, E;
+    X.push_back(0.0);
+    X.push_back(0.5);
+    X.push_back(1.0);
+    TS_ASSERT_THROWS_ANYTHING( ws->generateHistogram(2, X, Y, E); );
+    TS_ASSERT_THROWS_NOTHING( ws->generateHistogram(0, X, Y, E); );
+    TS_ASSERT_EQUALS( Y.size(), 2);
+    TS_ASSERT_EQUALS( E.size(), 2);
+    TS_ASSERT_DELTA( Y[0], 1.0, 1e-5);
+    TS_ASSERT_DELTA( Y[1], 1.0, 1e-5);
+    TS_ASSERT_DELTA( E[0], 1.0, 1e-5);
+    TS_ASSERT_DELTA( E[1], 1.0, 1e-5);
+  }
+
   void testDataDx()
   {
     TS_ASSERT_EQUALS( ws->readDx(0).size(), 6 );

Code/Mantid/Framework/TestHelpers/inc/MantidTestHelpers/FakeObjects.h

@@ -104,6 +104,7 @@ class WorkspaceTester : public MatrixWorkspace
   size_t blocksize() const {return vec[0].dataY().size();}
   ISpectrum * getSpectrum(const size_t index) { return &vec[index]; }
   const ISpectrum * getSpectrum(const size_t index) const { return &vec[index];; }
+  void generateHistogram(const std::size_t , const MantidVec& , MantidVec& , MantidVec& , bool ) const { }
 
 private:
   std::vector<SpectrumTester> vec;