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, 21.9.2000