Enhanced documentation. Refs #9766.

Code/Mantid/docs/source/algorithms/GeneratePeaks-v1.rst

@@ -9,16 +9,30 @@
 Description
 -----------
 
-Generate a workspace by summing over the peak functions. The peaks'
-parameters are given in a `TableWorkspace <http://www.mantidproject.org/TableWorkspace>`_.
+Generate a workspace by summing over the peak functions and optionally background functions.
+The peaks' and background'
+parameters are either (1) given in a `TableWorkspace <http://www.mantidproject.org/TableWorkspace>`_
+or (2) given by an array of doubles.
 
-Peak Parameters
-###############
+Function Parameters
+###################
 
+There are 2 different approaches to input parameter values of peak and background function.
 
-Peak parameters must have the following columns, which are case
+TableWorkspace
+##############
+##############
+
+Peak and background parameters must have the following columns, which are case
 sensitive in input `TableWorkspace <http://www.mantidproject.org/TableWorkspace>`_
 
+The definition of this table workspace is consistent with the output
+peak and background parameter `TableWorkspace <http://www.mantidproject.org/TableWorkspace>`_
+of algorithm FindPeaks.
+
+The following table contains the effective peak and background parameters.
+
+
 +------+--------------------+-------+
 |Column|          Name      |Comment|
 +======+====================+=======+
@@ -39,20 +53,112 @@ sensitive in input `TableWorkspace <http://www.mantidproject.org/TableWorkspace>
 |  8   | chi2               |       |
 +------+--------------------+-------+
 
+Double Array
+##############
+##############
+
+An alternative way to input function parameters is to specify parameter values
+in property 'PeakParameterValues' and 'BackgroundParameterValues'.
+
+In this case, there is only one peak function that can be specified and generated.
+
+The order of the parameters are pre-determined,
+which can be found in the dropdown list of 'PeakType' and 'BackgroundType'.
+For example in 'PeakType', there is an item named 'Gaussian(Height,PeakCentre, Sigma)'.
+Therefore, the order of parameters for Gaussian is height, peak centre and sigma.
+It does not matter whether 'Gaussian' or 'Gaussian(Height,PeakCentre, Sigma)' is selected.
+
+
+Effective Peak and Background Parameters
+########################################
 
-The background is a quadratic function 
+GeneratePeak supports effective peak and background parameters.
 
-.. math:: \mbox{A0}+\mbox{A1}*x+\mbox{A2}*x^2
+For peak parameters, the effective parameters are centre, height and FWHM.
+This order must be followed if the parameter values are input through 'PeakParameterValues'.
+
+For background parameters, the effective parameters are
+interception, slope and A2.
+This order must be followed if the parameter values are input through 'BackgroundParameterValues'.
 
 
 Output
 ######
 
-| ``Output will include``
-| ``1. pure peak``
-| ``2. pure background (with specified range of FWHM (int))``
-| ``3. peak + background``
+Output can be either pure peak with 'GenerateBackground' deselected or peak and background.
+
+If 'InputWorkspace', which is optional, is not given, then a single spectrum workspace can be generatged from scratch
+according to property 'BinningParameters'.
+
+
+Usage
+-----
+
+Generate peaks from a TableWorkspace
+####################################
+
+.. testcode:: GeneratePeakFromTable
+
+  # Create an input Tableworkspace by FindPeaks
+  Load(Filename='focussed.nxs', OutputWorkspace='focussed', LoaderName='LoadNexusProcessed',
+    LoaderVersion=1, LoadHistory=False)
+  FindPeaks(InputWorkspace='focussed', WorkspaceIndex=3, BackgroundType='Quadratic', PeaksList='PeakList3')
+
+  # Geneate peaks
+  GeneratePeaks(PeakParametersWorkspace='PeakList3', PeakType='Gaussian', BackgroundType='Quadratic',
+        InputWorkspace='focussed', NumberWidths=5, OutputWorkspace='GaussianPeak', IsRawParameter=False)
+
+  # Print
+  outws = mtd["GaussianPeak"]
+  vecx3 = outws.readX(3)
+  vecy3 = outws.readY(3)
+  for i in xrange(4277, 4283):
+    print "X = %f, Y = %f" % (vecx3[i], vecy3[i])
+
+.. testcleanup:: GeneratePeakFromTable
+
+  DeleteWorkspace(Workspace=outws)
+  DeleteWorkspace(Workspace="focussed")
+  DeleteWorkspace(Workspace="PeakList3")
+
+Output:
+
+.. testoutput:: GeneratePeakFromTable
+
+  X = 2.137026, Y = 24074.469544
+  X = 2.139414, Y = 25091.516123
+  X = 2.141805, Y = 25481.643702
+  X = 2.144199, Y = 25120.243602
+  X = 2.146595, Y = 24105.695010
+  X = 2.148994, Y = 22713.122811
+
+
+Generate peaks from arrays
+##########################
+
+
+.. testcode:: GeneratePeakFromArray
+
+  GeneratePeaks(PeakType='Gaussian (Height, PeakCentre, Sigma)', PeakParameterValues='10,1,0.2',
+      BackgroundType='Linear (A0, A1)', BackgroundParameterValues='5,1',
+      BinningParameters='0,0.01,20', NumberWidths=5, OutputWorkspace='GaussianPeak')
+
+  outws = mtd["GaussianPeak"]
+  for i in [92,93,94,95]:
+      print "X = %f, Y = %f" % (outws.readX(0)[i], outws.readY(0)[i])
+
+
+.. testcleanup:: GeneratePeakFromArray
+
+  DeleteWorkspace(Workspace=outws)
+
+Output:
 
+.. testoutput:: GeneratePeakFromArray
 
+  X = 0.920000, Y = 15.151163
+  X = 0.930000, Y = 15.335881
+  X = 0.940000, Y = 15.499975
+  X = 0.950000, Y = 15.642332
 
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