[Octave-cvsupdate] octave-forge/main/optiminterp/inst example_optiminterp.m, 1.1, 1.2 optiminterp1.m, 1.2, 1.3 optiminterp2.m, 1.2, 1.3 optiminterp3.m, 1.2, 1.3

[alex <aba...@us...>]

Update of /cvsroot/octave/octave-forge/main/optiminterp/inst
In directory sc8-pr-cvs3.sourceforge.net:/tmp/cvs-serv7638/inst

Modified Files:
	example_optiminterp.m optiminterp1.m optiminterp2.m 
	optiminterp3.m 
Log Message:
Improve example and fix typos

Index: optiminterp2.m
===================================================================
RCS file: /cvsroot/octave/octave-forge/main/optiminterp/inst/optiminterp2.m,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -d -r1.2 -r1.3
--- optiminterp2.m	13 Dec 2006 16:56:11 -0000	1.2
+++ optiminterp2.m	13 Dec 2006 17:20:30 -0000	1.3
@@ -31,7 +31,7 @@
 ##
 ## The background field of the optimal interpolation is zero.
 ## For a different background field, the background field
-## must be substracted from the observation, the difference 
+## must be subtracted from the observation, the difference 
 ## is mapped by OI onto the background grid and finally the
 ## background is added back to the interpolated field.
 ## The error variance of the background field is assumed to 

Index: example_optiminterp.m
===================================================================
RCS file: /cvsroot/octave/octave-forge/main/optiminterp/inst/example_optiminterp.m,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -d -r1.1 -r1.2
--- example_optiminterp.m	12 Dec 2006 23:29:54 -0000	1.1
+++ example_optiminterp.m	13 Dec 2006 17:20:30 -0000	1.2
@@ -1,6 +1,13 @@
 % Example program of the optimal interpolation toolbox
 
 
+% the grid onto which the observations are interpolated
+
+[xi,yi] = ndgrid(linspace(0,1,100));
+
+% background estimate or first guess
+xb = 10 + xi;
+
 % number of observations to interpolate
 
 on = 200;
@@ -13,15 +20,12 @@
 
 % the underlying function to interpolate
 
-f = sin(6*x) .* cos(6*y);
-
-% the error variance of the observations
-
-var = 0.0 * ones(on,1);
+yo = 10 + x + sin(6*x) .* cos(6*y);
 
-% the grid onto which the observations are interpolated
+% the error variance of the observations divided by the error 
+% variance of the background field
 
-[xi,yi] = ndgrid(linspace(0,1,100));
+var = 0.1 * ones(on,1);
 
 % the correlation length in x and y direction
 
@@ -32,8 +36,17 @@
 
 m = 30;
 
+% subtract the first guess from the observations
+% (DON'T FORGET THIS - THIS IS VERY IMPORTANT)
+
+Hxb = interp2(xi(:,1),yi(1,:),xb',x,y);
+f = yo - Hxb;
+
 % run the optimal interpolation
 % fi is the interpolated field and vari is its error variance
 
 [fi,vari] = optiminterp2(x,y,f,var,lenx,leny,m,xi,yi);
 
+% Add the first guess back
+
+xa = fi + xb;
\ No newline at end of file

Index: optiminterp1.m
===================================================================
RCS file: /cvsroot/octave/octave-forge/main/optiminterp/inst/optiminterp1.m,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -d -r1.2 -r1.3
--- optiminterp1.m	13 Dec 2006 16:56:11 -0000	1.2
+++ optiminterp1.m	13 Dec 2006 17:20:30 -0000	1.3
@@ -30,7 +30,7 @@
 ##
 ## The background field of the optimal interpolation is zero.
 ## For a different background field, the background field
-## must be substracted from the observation, the difference 
+## must be subtracted from the observation, the difference 
 ## is mapped by OI onto the background grid and finally the
 ## background is added back to the interpolated field.
 ## @end deftypefn

Index: optiminterp3.m
===================================================================
RCS file: /cvsroot/octave/octave-forge/main/optiminterp/inst/optiminterp3.m,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -d -r1.2 -r1.3
--- optiminterp3.m	13 Dec 2006 16:56:11 -0000	1.2
+++ optiminterp3.m	13 Dec 2006 17:20:30 -0000	1.3
@@ -32,7 +32,7 @@
 ##
 ## The background field of the optimal interpolation is zero.
 ## For a different background field, the background field
-## must be substracted from the observation, the difference 
+## must be subtracted from the observation, the difference 
 ## is mapped by OI onto the background grid and finally the
 ## background is added back to the interpolated field.
 ##