Greetings R members.
I have a few vectors that denote the 'steps' of different step functions
v1=c(3,4,5,1,2,3,4,5)
v2=c(5,6,2,4,7,3,2,5)
v3=c(1,2,4,7,3,1,3,5)
Here v1,v2,v3 are considered as the steps for the f1,f2,f3 step functions.
For example f1 looks like that (step size is always same and fixed)
f1= 3 (x>=-3,x<-2)
f1= 4 (x>=-2,x<-1)
f1= 5 (x>=-1,x<0)
f1= 1 (x>=0, x<1)
and so on.
What I only have are these vectors that are interpreted as functions (as shown
above, x (step is 1 here). I would like to ask your help of how I can create
some function that reads one of the vector v1,v2,v3.... and returns results that
are acceptable by integrate() function.
Usually integrate wants a pre-defined function like
myfunc(x)<-function{ x^2 }
but this is not the case here.
Could you please give me some hints how I can proceed?
I would like to thank u in advance for your help
Regards
Alex
try this:> f.main <- function(vec){+ breaks <- seq(-3, by = 1, length = length(vec) + 1L) + function(x){ + indx <- findInterval(x, breaks) + vec[indx] + } + }> f1 <- f.main(c(3,4,5,1,2,3,4,5)) > f2 <- f.main(c(5,6,2,4,7,3,2,5)) > f3 <- f.main(c(1,2,4,7,3,1,3,5)) > > f1(c(-2.5,-2,-.5,0,.5,1.5,2.5))[1] 3 4 5 1 1 2 3> f2(c(-2.5,-2,-.5,0,.5,1.5,2.5))[1] 5 6 2 4 4 7 3> f3(c(-2.5,-2,-.5,0,.5,1.5,2.5))[1] 1 2 4 7 7 3 1>On Mon, Jan 10, 2011 at 11:42 AM, Alaios <alaios at yahoo.com> wrote:> Greetings R members. > > I have a few vectors that denote the 'steps' of different step functions > v1=c(3,4,5,1,2,3,4,5) > v2=c(5,6,2,4,7,3,2,5) > v3=c(1,2,4,7,3,1,3,5) > > Here v1,v2,v3 are considered as the steps for the f1,f2,f3 step functions. > > For example f1 looks like that (step size is always same and fixed) > > f1= 3 (x>=-3,x<-2) > f1= 4 (x>=-2,x<-1) > f1= 5 (x>=-1,x<0) > f1= 1 (x>=0, x<1) > and so on. > > What I only have are these vectors that are interpreted as functions (as shown above, x (step is 1 here). I would like to ask your help of how I can create some function that reads one of the vector v1,v2,v3.... and returns results that are acceptable by integrate() function. > > Usually integrate wants a pre-defined function like > myfunc(x)<-function{ x^2 } > but this is not the case here. > > Could you please give me some hints how I can proceed? > > I would like to thank u in advance for your help > > Regards > Alex > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Jim Holtman Data Munger Guru What is the problem that you are trying to solve?
?approxfun -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.snow at imail.org 801.408.8111> -----Original Message----- > From: r-help-bounces at r-project.org [mailto:r-help-bounces at r- > project.org] On Behalf Of Alaios > Sent: Monday, January 10, 2011 9:43 AM > To: r-help at r-project.org > Subject: [R] From vector to a step function > > Greetings R members. > > I have a few vectors that denote the 'steps' of different step > functions > v1=c(3,4,5,1,2,3,4,5) > v2=c(5,6,2,4,7,3,2,5) > v3=c(1,2,4,7,3,1,3,5) > > Here v1,v2,v3 are considered as the steps for the f1,f2,f3 step > functions. > > For example f1 looks like that (step size is always same and fixed) > > f1= 3 (x>=-3,x<-2) > f1= 4 (x>=-2,x<-1) > f1= 5 (x>=-1,x<0) > f1= 1 (x>=0, x<1) > and so on. > > What I only have are these vectors that are interpreted as functions > (as shown above, x (step is 1 here). I would like to ask your help of > how I can create some function that reads one of the vector > v1,v2,v3.... and returns results that are acceptable by integrate() > function. > > Usually integrate wants a pre-defined function like > myfunc(x)<-function{ x^2 } > but this is not the case here. > > Could you please give me some hints how I can proceed? > > I would like to thank u in advance for your help > > Regards > Alex > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting- > guide.html > and provide commented, minimal, self-contained, reproducible code.