Set a numpy array for a spectrum in one go. Refs #6156

Code/Mantid/Framework/PythonInterface/mantid/api/src/Exports/MatrixWorkspace.cpp

@@ -12,6 +12,7 @@
 #include <boost/python/overloads.hpp>
 #include <boost/python/copy_const_reference.hpp>
 #include <boost/python/implicit.hpp>
+#include <boost/python/numeric.hpp>
 
 using namespace Mantid::API;
 using Mantid::Geometry::IDetector_sptr;
@@ -25,6 +26,7 @@ namespace
 {
   /// Typedef for data access, i.e. dataX,Y,E members
   typedef Mantid::MantidVec&(MatrixWorkspace::*data_modifier)(const std::size_t);
+
   /// return_value_policy for read-only numpy array
   typedef return_value_policy<Policies::VectorRefToNumpy<Converters::WrapReadOnly> > return_readonly_numpy;
   /// return_value_policy for read-write numpy array
@@ -34,6 +36,72 @@ namespace
   // Overloads for binIndexOf function which has 1 optional argument
   BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(MatrixWorkspace_binIndexOfOverloads,
                                          MatrixWorkspace::binIndexOf, 1, 2)
+
+  /**
+   * Set the values from an python array-style object into the given spectrum in the workspace
+   * @param self :: A reference to the calling object
+   * @param accessor :: A member-function pointer to the data{X,Y,E} member that will extract the writable values.
+   * @param wsIndex :: The workspace index for the spectrum to set
+   * @param values :: A numpy array. The length must match the size of the
+   */
+  void setSpectrumFromPyObject(MatrixWorkspace & self, data_modifier accessor,
+                               const size_t wsIndex, numeric::array values)
+  {
+    boost::python::tuple shape(values.attr("shape"));
+    if( boost::python::len(shape) != 1 )
+    {
+      throw std::invalid_argument("Invalid shape for setting 1D spectrum array, array is "
+          + boost::lexical_cast<std::string>(boost::python::len(shape)) + "D");
+    }
+    const size_t pyArrayLength = boost::python::extract<size_t>(shape[0]);
+    Mantid::MantidVec & wsArrayRef = (self.*accessor)(wsIndex);
+    const size_t wsArrayLength = wsArrayRef.size();
+
+    if(pyArrayLength != wsArrayLength)
+    {
+      throw std::invalid_argument("Length mismatch between workspace array & python array. ws="
+            + boost::lexical_cast<std::string>(wsArrayLength) + ", python=" + boost::lexical_cast<std::string>(pyArrayLength));
+    }
+    for(size_t i = 0; i < wsArrayLength; ++i)
+    {
+      wsArrayRef[i] = extract<double>(values[i]);
+    }
+  }
+
+
+  /**
+   * Set the X values from an python array-style object
+   * @param self :: A reference to the calling object
+   * @param wsIndex :: The workspace index for the spectrum to set
+   * @param values :: A numpy array. The length must match the size of the
+   */
+  void setXFromPyObject(MatrixWorkspace & self, const size_t wsIndex, numeric::array values)
+  {
+    setSpectrumFromPyObject(self, &MatrixWorkspace::dataX, wsIndex, values);
+  }
+
+  /**
+   * Set the Y values from an python array-style object
+   * @param self :: A reference to the calling object
+   * @param wsIndex :: The workspace index for the spectrum to set
+   * @param values :: A numpy array. The length must match the size of the
+   */
+  void setYFromPyObject(MatrixWorkspace & self, const size_t wsIndex, numeric::array values)
+  {
+    setSpectrumFromPyObject(self, &MatrixWorkspace::dataY, wsIndex, values);
+  }
+
+  /**
+   * Set the E values from an python array-style object
+   * @param self :: A reference to the calling object
+   * @param wsIndex :: The workspace index for the spectrum to set
+   * @param values :: A numpy array. The length must match the size of the
+   */
+  void setEFromPyObject(MatrixWorkspace & self, const size_t wsIndex, numeric::array values)
+  {
+    setSpectrumFromPyObject(self, &MatrixWorkspace::dataE, wsIndex, values);
+  }
+
 }
 
 void export_MatrixWorkspace()
@@ -61,13 +129,15 @@ void export_MatrixWorkspace()
          return_value_policy<copy_const_reference>(), "Returns the status of the distribution flag")
     .def("YUnit", &MatrixWorkspace::YUnit, "Returns the current Y unit for the data (Y axis) in the workspace")
     .def("YUnitLabel", &MatrixWorkspace::YUnitLabel, "Returns the caption for the Y axis")
+
     //--------------------------------------- Setters -------------------------------------------------------------------------------
     .def("setYUnitLabel", &MatrixWorkspace::setYUnitLabel, "Sets a new caption for the data (Y axis) in the workspace")
     .def("setYUnit", &MatrixWorkspace::setYUnit, "Sets a new unit for the data (Y axis) in the workspace")
     .def("setDistribution", (bool& (MatrixWorkspace::*)(const bool))&MatrixWorkspace::isDistribution,
        return_value_policy<return_by_value>(), "Set distribution flag. If True the workspace has been divided by the bin-width.")
     .def("replaceAxis", &MatrixWorkspace::replaceAxis)
-    //--------------------------------------- Data access ---------------------------------------------------------------------------
+
+    //--------------------------------------- Read spectrum data ---------------------------------------------------------------------------
     .def("readX", &MatrixWorkspace::readX, return_readonly_numpy(),
           "Creates a read-only numpy wrapper around the original X data at the given index")
     .def("readY", &MatrixWorkspace::readY, return_readonly_numpy(),
@@ -76,6 +146,8 @@ void export_MatrixWorkspace()
           "Creates a read-only numpy wrapper around the original E data at the given index")
     .def("readDx", &MatrixWorkspace::readDx, return_readonly_numpy(),
          "Creates a read-only numpy wrapper around the original Dx data at the given index")
+
+    //--------------------------------------- Write spectrum data ---------------------------------------------------------------------------
     .def("dataX", (data_modifier)&MatrixWorkspace::dataX, return_readwrite_numpy(),
          "Creates a writable numpy wrapper around the original X data at the given index")
     .def("dataY", (data_modifier)&MatrixWorkspace::dataY, return_readwrite_numpy(),
@@ -84,6 +156,11 @@ void export_MatrixWorkspace()
          "Creates a writable numpy wrapper around the original E data at the given index")
     .def("dataDx", (data_modifier)&MatrixWorkspace::dataDx, return_readwrite_numpy(),
         "Creates a writable numpy wrapper around the original Dx data at the given index")
+    .def("setX", &setXFromPyObject, "Set X values from a python list or numpy array. It performs a simple copy into the array.")
+    .def("setY", &setYFromPyObject, "Set Y values from a python list or numpy array. It performs a simple copy into the array.")
+    .def("setE", &setEFromPyObject, "Set E values from a python list or numpy array. It performs a simple copy into the array.")
+
+    // --------------------------------------- Extract data ---------------------------------------------------------------------------------
     .def("extractX", Mantid::PythonInterface::cloneX,
          "Extracts (copies) the X data from the workspace into a 2D numpy array. "
          "Note: This can fail for large workspaces as numpy will require a block "

Code/Mantid/Framework/PythonInterface/test/python/MatrixWorkspaceTest.py

@@ -3,7 +3,7 @@
 import math
 from testhelpers import run_algorithm, can_be_instantiated
 from mantid.api import (MatrixWorkspace, WorkspaceProperty, Workspace,
-                        ExperimentInfo, AnalysisDataService)
+                        ExperimentInfo, AnalysisDataService, WorkspaceFactory)
 from mantid.geometry import Detector
 from mantid.kernel import V3D
 
@@ -106,6 +106,61 @@ def do_numpy_test(arr):
         for attr in [x,y,e,dx]:
             do_numpy_test(attr)
 
+    def test_setting_spectra_from_array_of_incorrect_length_raises_error(self):
+        nvectors = 2
+        xlength = 11
+        ylength = 10
+        test_ws = WorkspaceFactory.create("Workspace2D", nvectors, xlength, ylength)
+
+        values = np.arange(xlength + 1)
+        self.assertRaises(ValueError, test_ws.setX, 0, values)
+        self.assertRaises(ValueError, test_ws.setY, 0, values)
+        self.assertRaises(ValueError, test_ws.setE, 0, values)
+
+    def test_setting_spectra_from_array_of_incorrect_shape_raises_error(self):
+        nvectors = 2
+        xlength = 11
+        ylength = 10
+        test_ws = WorkspaceFactory.create("Workspace2D", nvectors, xlength, ylength)
+
+        values = np.linspace(0,1,num=xlength-1)
+        values = values.reshape(5,2)
+        self.assertRaises(ValueError, test_ws.setX, 0, values)
+        self.assertRaises(ValueError, test_ws.setY, 0, values)
+        self.assertRaises(ValueError, test_ws.setE, 0, values)
+
+    def test_setting_spectra_from_array_using_incorrect_index_raises_error(self):
+        nvectors = 2
+        xlength = 11
+        ylength = 10
+
+        test_ws = WorkspaceFactory.create("Workspace2D", nvectors, xlength, ylength)
+        xvalues = np.arange(xlength)
+        self.assertRaises(RuntimeError, test_ws.setX, 3, xvalues)
+
+    def test_setting_spectra_from_array_sets_expected_values(self):
+        nvectors = 2
+        xlength = 11
+        ylength = 10
+
+        test_ws = WorkspaceFactory.create("Workspace2D", nvectors, xlength, ylength)
+        ws_index = 1
+
+        values = np.linspace(0,1,xlength)
+        test_ws.setX(ws_index, values)
+        ws_values = test_ws.readX(ws_index)
+        self.assertTrue(np.array_equal(values, ws_values))
+
+        values = np.ones(ylength)
+        test_ws.setY(ws_index, values)
+        ws_values = test_ws.readY(ws_index)
+        self.assertTrue(np.array_equal(values, ws_values))
+
+        values = np.sqrt(values)
+        test_ws.setE(ws_index, values)
+        ws_values = test_ws.readE(ws_index)
+        self.assertTrue(np.array_equal(values, ws_values))
+
     def test_data_can_be_extracted_to_numpy_successfully(self):
         x = self._test_ws.extractX()
         y = self._test_ws.extractY()