Merge pull request #38801 from mantidproject/EWM8982-throw-exception

Matrix Workspace throw exception for invalid plot argument

Framework/API/src/MatrixWorkspace.cpp

@@ -333,15 +333,12 @@ void MatrixWorkspace::setPlotType(const std::string &t) {
   StringListValidator v(validPlotTypes);
 
   if (v.isValid(t) == "") {
-    if (run.hasProperty("plot_type"))
-      run.addProperty("plot_type", t, true);
-    else
-      run.addProperty("plot_type", t, false);
+    run.addProperty("plot_type", t, true);
   } else {
     std::string validValues = std::accumulate(
         validPlotTypes.begin() + 1, validPlotTypes.end(), validPlotTypes.front(),
         [](const std::string &valuesString, const std::string &plotType) { return valuesString + ", " + plotType; });
-    g_log.warning("Invalid plot type '" + t + "'. Must be one of: " + validValues);
+    throw std::invalid_argument("Invalid plot type '" + t + "'. Must be one of: " + validValues);
   }
 }
 
@@ -375,7 +372,7 @@ void MatrixWorkspace::setMarkerStyle(const std::string &markerType) {
                         [](const std::string &valuesString, const std::string &markerStyle) {
                           return valuesString + ", " + markerStyle;
                         });
-    g_log.warning("Invalid marker type '" + markerType + "'. Must be one of: " + validValues);
+    throw std::invalid_argument("Invalid marker type '" + markerType + "'. Must be one of: " + validValues);
   }
 }
 

Framework/API/test/MatrixWorkspaceTest.h

@@ -407,7 +407,7 @@ class MatrixWorkspaceTest : public CxxTest::TestSuite {
     TS_ASSERT_EQUALS(ws->getPlotType(), "plot");
 
     // test invalid is rejected
-    ws->setPlotType("invalid");
+    TS_ASSERT_THROWS(ws->setPlotType("invalid"), const std::invalid_argument &);
     TS_ASSERT_EQUALS(ws->getPlotType(), "plot");
 
     // test valid is accepted
@@ -419,6 +419,9 @@ class MatrixWorkspaceTest : public CxxTest::TestSuite {
     // test default
     TS_ASSERT_EQUALS(ws->getMarkerStyle(), "vline");
 
+    TS_ASSERT_THROWS(ws->setMarkerStyle("invalid"), const std::invalid_argument &);
+    TS_ASSERT_EQUALS(ws->getMarkerStyle(), "vline");
+
     // test set
     ws->setMarkerStyle("square");
     TS_ASSERT_EQUALS(ws->getMarkerStyle(), "square");

Framework/PythonInterface/test/python/mantid/api/MatrixWorkspaceTest.py

@@ -404,7 +404,7 @@ def test_setPlotType(self):
         self.assertEqual("plot", ws1.getPlotType())
 
         # test invalid doesn't take
-        ws1.setPlotType("invalid")
+        self.assertRaisesRegex(ValueError, "Invalid plot type", ws1.setPlotType, "invalid")
         self.assertEqual("plot", ws1.getPlotType())
 
         # test valid takes
@@ -419,7 +419,7 @@ def test_setMarkerStyle(self):
         self.assertEqual("vline", ws1.getMarkerStyle())
 
         # test invalid doesn't take
-        ws1.setMarkerStyle("invalid")
+        self.assertRaisesRegex(ValueError, "Invalid marker type", ws1.setMarkerStyle, "invalid")
         self.assertEqual("vline", ws1.getMarkerStyle())
 
         # test valid takes

docs/source/api/python/mantid/plots/index.rst

@@ -188,6 +188,7 @@ when giving the projection:
 Matrix Workspace Plotting
 =========================
 
+The :ref:`Matrix Workspace <MatrixWorkspace_Plotting>` has some additional features that help simplify plotting data.
 The `setPlotType()` method allows you to define how a workspace should be visualized when plotting. The following plot types are available:
 
 - **marker**:

docs/source/concepts/MatrixWorkspace.rst

@@ -284,13 +284,16 @@ Output:
   Counts
   Elephants
 
+.. _MatrixWorkspace_Plotting:
+
 Plotting
 ^^^^^^^^
-.. _MatrixWorkspace_Plotting:
 
 You can specify the type of plot to be used when plotting a Matrix Workspace. The following plot types are available:
-``plot``, ``marker``, ``errorbar_x``, ``errorbar_y``, ``errorbar_xy``, with ``plot`` as the default.
-Changing the plot type will affect the way the data is displayed and can be changed in the following way:
+``plot``, ``marker``, ``errorbar_x``, ``errorbar_y``, ``errorbar_xy``. By default all Matrix Workspaces will be
+treated as a ``plot`` type and this value will not auto-update or affect existing workspace plots. Changing the plot
+type will affect the way the data is displayed. An example of the different plot types can be seen in :ref:`mantid.plots`.
+Below is a simple example changing the plot type, a full example is available in the :ref:`plotting gallery<MarkerWS_Example>` page.
 
 .. testsetup:: MatrixWorkspacePlotType
 

docs/source/plotting/index.rst

@@ -308,6 +308,45 @@ Some data should be visualized as two dimensional colormaps
    cbar.set_label('Intensity (arb. units)') #add text to colorbar
    #fig.show()
 
+.. _MarkerWS_Example:
+
+Some data is best visualized as a Marker type workspace with no lines connecting the points.
+:ref:`Matrix workspace<MatrixWorkspace_Plotting>` has some built-in functions to simplify plotting Marker type workspaces.
+
+.. plot::
+   :include-source:
+
+   import numpy as np
+   import matplotlib.pyplot as plt
+   from mantid import plots
+   from mantid.simpleapi import CreateWorkspace
+
+   # Generate random x and y values for two workspaces
+   x1 = np.arange(20)
+   y1 = np.random.uniform(5, 50, len(x1))  # Random values between 5 and 50
+
+   x2 = np.arange(20)
+   y2 = np.random.uniform(10, 55, len(x2))  # Different random values
+
+   # Create a marker workspace
+   w1 = CreateWorkspace(DataX=x1, DataY=y1, NSpec=1)
+   w1.setPlotType('marker')
+
+   # Create a second marker workspace
+   w2 = CreateWorkspace(DataX=x2, DataY=y2, NSpec=1)
+   w2.setPlotType('marker')
+   w2.setMarkerStyle('circle')
+   w2.setMarkerSize(4)
+
+   # Plot using the mantid projection
+   fig, ax = plt.subplots(subplot_kw={'projection': 'mantid'})
+   ax.plot(w1)  # First marker workspace
+   ax.plot(w2)  # Second marker workspace with different style marker
+
+   ax.set_title("Marker Workspace Example")  # Set plot title
+   ax.legend()  # Show the legend
+   plt.show()
+
 One can then change properties of the plot. Here is an example that
 changes the label of the data, changes the label of the x and y axis,
 changes the limits for the y axis, adds a title, change tick orientations,