Changeset 5144

Timestamp:

Mar 10, 2008, 11:53:33 AM (17 years ago)

Author:

nick

Message:

add information about 'find_optimal_smoothing_parameter' to the user_manual/anuga_user_manual.tex. Closing trac ticket 216

File:

• anuga_core/documentation/user_manual/anuga_user_manual.tex (modified) (2 diffs)

anuga_core/documentation/user_manual/anuga_user_manual.tex

@@ -3692 +3692 @@
 new object are disjoin set of each other.
         
-Points of the two new object have selected RANDOMLY. 
+Points of the two new geospatial_data object are selected RANDOMLY. 
         
-Input - the factor which to split the object, if 0.1 then 10% of the
+Input - the (\code{factor}) which to split the object, if 0.1 then 10% of the
 together object will be returned
         
@@ -3703 +3703 @@
 north_boundary=None, south_boundary=None, east_boundary=None, west_boundary=None, plot_name='all_alphas', split_factor=0.1, seed_num=None, cache=False, verbose=False}
 
-Returns two geospatial_data object, first is the size of the 'factor'
-smaller the original and the second is the remainder. The two
-new object are disjoin set of each other.
-        
-Points of the two new object have selected RANDOMLY. 
-        
-Input - the factor which to split the object, if 0.1 then 10% of the
-together object will be returned
-        
-Output - two geospatial_data objects that are disjoint sets of the original
+Removes a small random sample of points from 'data_file'. Creates 
+models from resulting points in 'data_file' with different alpha values from 'alpha_list' and cross validates 
+the predicted value to the previously removed point data. Returns the
+alpha value which has the smallest covariance.
+
+data_file: must not contain points outside the boundaries defined
+and it either a pts, txt or csv file. 
+    
+alpha_list: the alpha values to test in a single list
+    
+mesh_file: name of the created mesh file or if passed in will read it. 
+NOTE, if there is a mesh file mesh_resolution, north_boundary, south... etc will be ignored.
+    
+mesh_resolution: the maximum area size for a triangle
+    
+north_boundary... west_boundary: the value of the boundary
+    
+plot_name: the name for the plot contain the results
+    
+seed_num: the seed to the random number generator
+    
+USAGE:
+convariance_value, alpha = find_optimal_smoothing_parameter(data_file=fileName, 
+                                             alpha_list=[0.0001, 0.01, 1],
+                                             mesh_file=None,
+                                             mesh_resolution=3,
+                                             north_boundary=5,
+                                             south_boundary=-5,
+                                             east_boundary=5,
+                                             west_boundary=-5,
+                                             plot_name='all_alphas',
+                                             seed_num=100000,
+                                             verbose=False)
+    
+OUTPUT: returns the minumum normalised covalance calculate AND the 
+alpha that created it. PLUS writes a plot of the results
+           
+NOTE: code will not work if the data_file extent is greater than the
+boundary_polygon or any of the boundaries, eg north_boundary...west_boundary
 \end{methoddesc}