Keywords - Function groups - @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Group: Statistical Data Analysis
Topic: Nonparametric Methods
See also: isoreg sknn rmed l1line lowess

Function: sker
Description: sker computes a direct kernel estimate without binning from scatter plot data.


Reference(s):

Usage: z = sker (x, h, K, y {, xest})
Input:
x n x p x d1 x ... x dn array
h 1 x p x d1 x ... x dn array (global bandwidth)
n x p x d1 x ... x dn array (local bandwidth)
K text (kernel)
y n x m x d1 x ... x dn array
xest k x p x d1 x ... x dn array
Output:
z k x m x d1 x ... x dn array

Note:

Example:

library("kernel")        ; loading the quartic kernel
x = 2.*uniform(100)-1
x = sort(x)
y = 5*x^2+0.5*normal(100)
d = createdisplay(1,1)
;
r = sker (x, 0.25, "qua", y)
f = sker (x, 0.25, "qua", matrix(100))
mh = r./f                ; nadaraya-watson estimator on x
show(d, 1, 1, x~y, x~mh)
; continuing using xest
xest = 2.*(0:100)/100-1
r = sker (x, 0.25, "qua", y, xest)
f = sker (x, 0.25, "qua", matrix(100), xest)
mh = r./f                ; nadaraya-watson estimator on xest
show(d, 1, 1, x~y, xest~mh)
Result:

Group: Statistical Data Analysis
Topic: Nonparametric Methods
See also: isoreg sknn rmed l1line lowess

Keywords - Function groups - @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

(C) MD*TECH Method and Data Technologies, 28.6.1999