more info on ParentWorkspace, re #10587

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

@@ -9,12 +9,21 @@
 Description
 -----------
 
-This algorithm constructs a MatrixWorkspace when passed a vector for each
-of the X, Y, and E data values. The unit for the X Axis can optionally be
-specified as any of the units in the Kernel's UnitFactory.  Multiple spectra
-may be created by supplying the NSpec Property (integer, default 1). When
-this is provided the vectors are split into equal-sized spectra (all X, Y,
-E values must still be in a single vector for input).
+This algorithm constructs a :ref:`MatrixWorkspace <MatrixWorkspace>`
+when passed a vector for each of the X, Y, and E data values. The unit
+for the X Axis can optionally be specified as any of the units in the
+Mantid `Unit Factory <http://www.mantidproject.org/Units>`__ (see `the
+list of units currently available
+<http://www.mantidproject.org/Units>`__).  Multiple spectra may be
+created by supplying the NSpec Property (integer, default 1). When
+this is provided the vectors are split into equal-sized spectra (all
+X, Y, E values must still be in a single vector for input).
+
+When you use the input property ParentWorkspace, the new workspace is
+created with the same instrument (including its parameters), sample
+and run information, and comment field as the parent. The Y units and
+title are also copied from the parent workspace unless they are
+provided in the input properties passed to the algorithm.
 
 Usage
 -----