Added Vesuvio resolution algorithm

Refs #10346

Code/Mantid/Framework/PythonInterface/plugins/algorithms/VesuvioResolution.py

+from mantid.simpleapi import *
+from mantid.api import *
+from mantid.kernel import *
+import mantid
+
+
+class VesuvioResolution(PythonAlgorithm):
+
+    def category(self):
+        return 'Inelastic'
+
+    def summary(self):
+        return 'Calculates the resolution function for VESUVIO'
+
+    def PyInit(self):
+        self.declareProperty(WorkspaceProperty(name='Sample',
+                                               defaultValue='',
+                                               direction=Direction.Input),
+                             doc='Sample workspace')
+
+        self.declareProperty(name='SpectraIndex', defaultValue=0,
+                             doc='Spectra index to use for resolution')
+
+        self.declareProperty(name='Mass', defaultValue=100.0,
+                             doc='The mass defining the recoil peak in AMU')
+
+        self.declareProperty(name='OutputMode', defaultValue='TOF',
+                             validator=StringListValidator(['TOF', 'y-Space']),
+                             doc='')
+
+        self.declareProperty(WorkspaceProperty(name='OutputWorkspace',
+                                               defaultValue='',
+                                               direction=Direction.Output),
+                             doc='Output resolution workspace')
+
+
+    def PyExec(self):
+        sample_ws = self.getPropertyValue('Sample')
+        out_ws = self.getPropertyValue('OutputWorkspace')
+        spectrum_index = self.getProperty('SpectraIndex').value
+        mass = self.getProperty('Mass').value
+        output_mode = self.getPropertyValue('OutputMode')
+
+        function = 'name=VesuvioResolution, Mass=%f' % mass
+        fit_naming_stem = '__vesuvio_res_fit'
+
+        # Execute the resolution function using fit.
+        # Functions can't currently be executed as stand alone objects,
+        # so for now we will run fit with zero iterations to achieve the same result.
+        fit = mantid.api.AlgorithmManager.createUnmanaged('Fit')
+        fit.initialize()
+        fit.setChild(True)
+        fit.setLogging(False)
+        mantid.simpleapi._set_properties(fit, function, sample_ws, MaxIterations=0,
+                CreateOutput=True, Output=fit_naming_stem, WorkspaceIndex=spectrum_index,
+                OutputCompositeMembers=True)
+        fit.execute()
+        fit_ws = fit.getProperty("OutputWorkspace").value
+
+        # Extract just the function values from the fit spectrum
+        extract = mantid.api.AlgorithmManager.createUnmanaged('ExtractSingleSpectrum')
+        extract.initialize()
+        extract.setChild(True)
+        extract.setLogging(False)
+        extract.setProperty("InputWorkspace", fit_ws)
+        extract.setProperty("OutputWorkspace", out_ws)
+        extract.setProperty("WorkspaceIndex", 1)
+        extract.execute()
+        out_ws = extract.getProperty('OutputWorkspace').value
+
+        # Convert to y-Space if needed
+        if output_mode == 'y-Space':
+            pass
+
+        self.setProperty('OutputWorkspace', out_ws)
+
+
+AlgorithmFactory.subscribe(VesuvioResolution)