Re: [R] Plotting a segmented function
Try
f - function(x){
if(x = 0) return(0)
if( 0 x x = 1 ) return( 0.5*x^2 )
if( 1 x x = 2 ) return( -0.5*x^2 + 2*x - 1 )
return(1)
}
xx - seq(-1, 3, 0.1)
yy - sapply(xx, f)
Regards, Adai
On Thu, 2006-03-30 at 09:25 -0200, Ken Knoblauch wrote:
You could try nested ifelse statements,
something like (untested)
x - seq(-1, 3, 0.1)
y - ifelse( x = 3,
ifelse( x = 2,
ifelse( x = 1,
ifelse( x = 0, 0, x^2/2), 2 * x - (x^2/2) -1), 1) )
plot(x, y)
**
This might be a trivial question, but I would appreciate if anybody
could suggest an elegant way of plotting a function such as the
following (a simple distribution function):
F(x) = 0 if x=0
=(x^2)/2 if 0x=1
=2x-((x^2)/2)-1 if 1x=2
=1 if x2
This is just an example. In this case it is a continuous function. But
how to do it in general in an elegant way.
I've done the following:
x1 - seq(-1,0,.01)
f1 - rep(0,101)
x2 - seq(0,1,.01)
f2 - 0.5*(x2^2)
x3 - seq(1,2,.01)
f3 - (2*x3)-(0.5*(x3^2))-1
x4 - seq(2,3,.01)
f4 - rep(1,101)
x - c(x1,x2,x3,x4)
F - c(f1,f2,f3,f4)
plot(x,F,type='l')
But this seems very cumbersome.
Any help is much appreciated.
Thanks
Jacob
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[R] Plotting a segmented function
This might be a trivial question, but I would appreciate if anybody could suggest an elegant way of plotting a function such as the following (a simple distribution function): F(x) = 0 if x=0 =(x^2)/2 if 0x=1 =2x-((x^2)/2)-1 if 1x=2 =1 if x2 This is just an example. In this case it is a continuous function. But how to do it in general in an elegant way. I've done the following: x1 - seq(-1,0,.01) f1 - rep(0,101) x2 - seq(0,1,.01) f2 - 0.5*(x2^2) x3 - seq(1,2,.01) f3 - (2*x3)-(0.5*(x3^2))-1 x4 - seq(2,3,.01) f4 - rep(1,101) x - c(x1,x2,x3,x4) F - c(f1,f2,f3,f4) plot(x,F,type='l') But this seems very cumbersome. Any help is much appreciated. Thanks Jacob Jacob L van Wyk Department of Statistics University of Johannesburg APK P O Box 524 Auckland Park 2006 South Africa Tel: +27-11-489-3080 Fax: +27-11-489-2832 __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Plotting a segmented function
Jacob van Wyk wrote:
This might be a trivial question, but I would appreciate if anybody
could suggest an elegant way of plotting a function such as the
following (a simple distribution function):
F(x) = 0 if x=0
=(x^2)/2 if 0x=1
=2x-((x^2)/2)-1 if 1x=2
=1 if x2
This is just an example. In this case it is a continuous function. But
how to do it in general in an elegant way.
I've done the following:
x1 - seq(-1,0,.01)
f1 - rep(0,101)
x2 - seq(0,1,.01)
f2 - 0.5*(x2^2)
x3 - seq(1,2,.01)
f3 - (2*x3)-(0.5*(x3^2))-1
x4 - seq(2,3,.01)
f4 - rep(1,101)
x - c(x1,x2,x3,x4)
F - c(f1,f2,f3,f4)
plot(x,F,type='l')
But this seems very cumbersome.
Any help is much appreciated.
Define a function such as
f - function(x){
(x2) +
(2*x-((x^2)/2)-1) * ((1 x) (x = 2)) +
((x^2)/2) * ((0 x) (x = 1))
}
curve(f, from = -1, to = 3)
Thanks
Jacob
Jacob L van Wyk
Department of Statistics
University of Johannesburg APK
P O Box 524
Auckland Park 2006
South Africa
Tel: +27-11-489-3080
Fax: +27-11-489-2832
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R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
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R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
[R] Plotting a segmented function
You could try nested ifelse statements, something like (untested) x - seq(-1, 3, 0.1) y - ifelse( x = 3, ifelse( x = 2, ifelse( x = 1, ifelse( x = 0, 0, x^2/2), 2 * x - (x^2/2) -1), 1) ) plot(x, y) ** This might be a trivial question, but I would appreciate if anybody could suggest an elegant way of plotting a function such as the following (a simple distribution function): F(x) = 0 if x=0 =(x^2)/2 if 0x=1 =2x-((x^2)/2)-1 if 1x=2 =1 if x2 This is just an example. In this case it is a continuous function. But how to do it in general in an elegant way. I've done the following: x1 - seq(-1,0,.01) f1 - rep(0,101) x2 - seq(0,1,.01) f2 - 0.5*(x2^2) x3 - seq(1,2,.01) f3 - (2*x3)-(0.5*(x3^2))-1 x4 - seq(2,3,.01) f4 - rep(1,101) x - c(x1,x2,x3,x4) F - c(f1,f2,f3,f4) plot(x,F,type='l') But this seems very cumbersome. Any help is much appreciated. Thanks Jacob -- Ken Knoblauch Inserm U371 Cerveau et Vision Dept. of Cognitive Neuroscience 18 avenue du Doyen Lépine 69500 Bron France tel: +33 (0)4 72 91 34 77 fax: +33 (0)4 72 91 34 61 portable: +33 (0)6 84 10 64 10 http://www.lyon.inserm.fr/371/ __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
