Re: [R] How to use curve() function without using x as the variable name inside expression?
Hi Philippe,
Ah! Thanks for pointing out the pesky ifelse() issue. I have only recently
been learning (the hard way) that ifelse() is not a tool for the uninformed
like me, but it is ever so tempting!
I would like to offer another way to speed things up. findInterval() can be
quite fast, and the speed up is most noticeable when the size of the input
grows (note I made input x <- 1:3000).
func <- function (x, mn, mx) 1/(mx-mn) * (x >= mn & x <= mx)
funcIfElse <- function (x, mn, mx) ifelse(x < mn | x > mx, 0, 1/(mx - mn))
funcFindInterval <- function(x, mn, mx) 1/(mx - mn) * (findInterval(x, c(mn,
mx), rightmost.closed = TRUE) == 1)
mn<- 100; mx <- 200; x <- 1:3000
microbenchmark::microbenchmark(func(x, mn, mx), funcIfElse(x, mn, mx),
funcFindInterval(x, mn, mx))
#Unit: microseconds
#expr min lq mean median uq
max neval
# func(x, mn, mx) 74.920 76.006 88.57119 76.5635 78.7065
897.333 100
# funcIfElse(x, mn, mx) 728.388 733.206 832.02225 735.4280 796.1910
1645.804 100
# funcFindInterval(x, mn, mx) 33.954 35.334 56.57323 36.5010 38.3340
993.193 100
r1 <- func(x, mn, mx)
r2 <- funcIfElse(x, mn, mx)
r3 <- funcFindInterval(x, mn, mx)
identical(r1, r2)
#[1] TRUE
identical(r2, r3)
#[1] TRUE
Cheers,
Ben
On Jan 31, 2015, at 4:03 AM, Philippe Grosjean wrote:
> Also note that ifelse() should be avoided as much as possible. To define a
> piecewise function you can use this trick:
>
> func <- function (x, min, max) 1/(max-min) * (x >= min & x <= max)
>
> The performances are much better. This has no impact here, but it is a good
> habit to take in case you manipulate such kind of functions in a more
> computing-intensive context (numerical integration, nls(), etc.).
>
> funcIfElse <- function (x, min, max) ifelse(x < min | x > max, 0, 1/(max -
> min))
> min <- 100; max <- 200; x <- 1:300
> microbenchmark::microbenchmark(func(x, min, max), funcIfElse(x, min, max))
> ## Unit: microseconds
> ## exprmin lq mean median
> uq max neval
> ## func(x, min, max) 10.242 16.0175 18.43348 18.446 19.8680
> 47.266 100
> ## funcIfElse(x, min, max) 90.386 125.1605 148.18555 143.455 148.6695
> 1203.292 100
>
> Best,
>
> Philippe Grosjean
>
>> On 31 Jan 2015, at 09:39, Rolf Turner wrote:
>>
>> On 31/01/15 21:10, C W wrote:
>>> Hi Bill,
>>>
>>> One quick question. What if I wanted to use curve() for a uniform
>>> distribution?
>>>
>>> Say, unif(0.5, 1.3), 0 elsewhere.
>>>
>>> My R code:
>>> func <- function(min, max){
>>> 1 / (max - min)
>>> }
>>>
>>> curve(func(min = 0.5, max = 1.3), from = 0, to = 2)
>>>
>>> curve() wants an expression, but I have a constant. And I want zero
>>> everywhere else.
>>
>> Well if that's what you want, then say so!!!
>>
>> func <- function(x,min,max) {
>> ifelse(x < min | x > max, 0, 1/(max - min))
>> }
>>
>> curve(func(u,0.5,1.3),0,2,xname="u")
>>
>> Or, better (?) curve(func(u,0.5,1.3),0,2,xname="u",type="s")
>>
>> which avoids the slight slope in the "vertical" lines.
>>
>> cheers,
>>
>> Rolf Turner
>>
>> --
>> Rolf Turner
>> Technical Editor ANZJS
>> Department of Statistics
>> University of Auckland
>> Phone: +64-9-373-7599 ext. 88276
>> Home phone: +64-9-480-4619
>>
>> __
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
__
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Re: [R] How to use curve() function without using x as the variable name inside expression?
Also note that ifelse() should be avoided as much as possible. To define a
piecewise function you can use this trick:
func <- function (x, min, max) 1/(max-min) * (x >= min & x <= max)
The performances are much better. This has no impact here, but it is a good
habit to take in case you manipulate such kind of functions in a more
computing-intensive context (numerical integration, nls(), etc.).
funcIfElse <- function (x, min, max) ifelse(x < min | x > max, 0, 1/(max - min))
min <- 100; max <- 200; x <- 1:300
microbenchmark::microbenchmark(func(x, min, max), funcIfElse(x, min, max))
## Unit: microseconds
## exprmin lq mean median
uq max neval
## func(x, min, max) 10.242 16.0175 18.43348 18.446 19.8680
47.266 100
## funcIfElse(x, min, max) 90.386 125.1605 148.18555 143.455 148.6695 1203.292
100
Best,
Philippe Grosjean
> On 31 Jan 2015, at 09:39, Rolf Turner wrote:
>
> On 31/01/15 21:10, C W wrote:
>> Hi Bill,
>>
>> One quick question. What if I wanted to use curve() for a uniform
>> distribution?
>>
>> Say, unif(0.5, 1.3), 0 elsewhere.
>>
>> My R code:
>> func <- function(min, max){
>> 1 / (max - min)
>> }
>>
>> curve(func(min = 0.5, max = 1.3), from = 0, to = 2)
>>
>> curve() wants an expression, but I have a constant. And I want zero
>> everywhere else.
>
> Well if that's what you want, then say so!!!
>
> func <- function(x,min,max) {
> ifelse(x < min | x > max, 0, 1/(max - min))
> }
>
> curve(func(u,0.5,1.3),0,2,xname="u")
>
> Or, better (?) curve(func(u,0.5,1.3),0,2,xname="u",type="s")
>
> which avoids the slight slope in the "vertical" lines.
>
> cheers,
>
> Rolf Turner
>
> --
> Rolf Turner
> Technical Editor ANZJS
> Department of Statistics
> University of Auckland
> Phone: +64-9-373-7599 ext. 88276
> Home phone: +64-9-480-4619
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] How to use curve() function without using x as the variable name inside expression?
> On 31 Jan 2015, at 09:39 , Rolf Turner wrote:
>
> On 31/01/15 21:10, C W wrote:
>> Hi Bill,
>>
>> One quick question. What if I wanted to use curve() for a uniform
>> distribution?
>>
>> Say, unif(0.5, 1.3), 0 elsewhere.
>>
>> My R code:
>> func <- function(min, max){
>> 1 / (max - min)
>> }
>>
>> curve(func(min = 0.5, max = 1.3), from = 0, to = 2)
>>
>> curve() wants an expression, but I have a constant. And I want zero
>> everywhere else.
>
> Well if that's what you want, then say so!!!
>
> func <- function(x,min,max) {
> ifelse(x < min | x > max, 0, 1/(max - min))
> }
>
Oy! help(Uniform) called. I wants its density function back...
> curve(func(u,0.5,1.3),0,2,xname="u")
>
> Or, better (?) curve(func(u,0.5,1.3),0,2,xname="u",type="s")
>
> which avoids the slight slope in the "vertical" lines.
It might put the verticals in the wrong place though. I usually just increase
the "n" parameter:
curve(dunif(u,.5, 1.3), from=0, to=2, n=5001, xname="u")
--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd@cbs.dk Priv: pda...@gmail.com
__
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and provide commented, minimal, self-contained, reproducible code.
Re: [R] How to use curve() function without using x as the variable name inside expression?
On 31/01/15 21:10, C W wrote:
Hi Bill,
One quick question. What if I wanted to use curve() for a uniform
distribution?
Say, unif(0.5, 1.3), 0 elsewhere.
My R code:
func <- function(min, max){
1 / (max - min)
}
curve(func(min = 0.5, max = 1.3), from = 0, to = 2)
curve() wants an expression, but I have a constant. And I want zero
everywhere else.
Well if that's what you want, then say so!!!
func <- function(x,min,max) {
ifelse(x < min | x > max, 0, 1/(max - min))
}
curve(func(u,0.5,1.3),0,2,xname="u")
Or, better (?) curve(func(u,0.5,1.3),0,2,xname="u",type="s")
which avoids the slight slope in the "vertical" lines.
cheers,
Rolf Turner
--
Rolf Turner
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276
Home phone: +64-9-480-4619
__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] How to use curve() function without using x as the variable name inside expression?
Hi Bill,
One quick question. What if I wanted to use curve() for a uniform
distribution?
Say, unif(0.5, 1.3), 0 elsewhere.
My R code:
func <- function(min, max){
1 / (max - min)
}
curve(func(min = 0.5, max = 1.3), from = 0, to = 2)
curve() wants an expression, but I have a constant. And I want zero
everywhere else.
Thanks,
Mike
On Thu, Jan 29, 2015 at 10:34 PM, C W wrote:
> Hi Bill,
>
> You solved by problem. For some reason, I thought xname was only
> referring to name of the x-axis.
>
> I remember last time I fixed it, it was something about xname, couldn't
> get it right this time.
>
> Thanks! Saved me hours from frustration.
>
> Mike
>
> On Thu, Jan 29, 2015 at 9:04 PM, William Dunlap wrote:
>
>> Does
>>help(curve)
>> talk about its 'xname' argument?
>>
>> Try
>>curve(10*foofoo, from=0, to=17, xname="foofoo")
>>
>> You will have to modify your function, since curve() will
>> call it once with a long vector for the independent variable
>> and func(rnorm(10), rnorm(10), mu=seq(0,5,len=501)) won't
>> work right.
>>
>>
>> Bill Dunlap
>> TIBCO Software
>> wdunlap tibco.com
>>
>> On Thu, Jan 29, 2015 at 5:43 PM, C W wrote:
>>
>>> Hi Rui,
>>>
>>> Thank you for your help. That works for now, but eventually, I need to
>>> be
>>> pass in x and y.
>>>
>>> Is there a way to tell the curve() function, x is a fix vector, mu is a
>>> variable!
>>>
>>> Thanks,
>>>
>>> Mike
>>>
>>> On Thu, Jan 29, 2015 at 5:25 PM, Rui Barradas
>>> wrote:
>>>
>>> > Hello,
>>> >
>>> > The following will work, but I don't know if it's what you want. func2
>>> > will get x and y from the global environment.
>>> >
>>> > func2 <- function(mu){
>>> >x + y + mu ^ 2
>>> > }
>>> >
>>> > curve(func2, from = 0, to = 10)
>>> >
>>> >
>>> > Hope this helps,
>>> >
>>> > Rui Barradas
>>> >
>>> > Em 29-01-2015 21:02, C W escreveu:
>>> >
>>> >> Hi all,
>>> >>
>>> >> I want to graph a curve as a function of mu, not x.
>>> >>
>>> >> Here's the R code:
>>> >>
>>> >> x <- rnorm(10)
>>> >> y <- rnorm(10)
>>> >>
>>> >> func <- function(x, y, mu){
>>> >> x + y + mu ^ 2
>>> >> }
>>> >>
>>> >> curve(f = func(x = x, y = y, mu), from = 0, to = 10)
>>> >> I know I can change variable mu to x, but is there a way to tell R
>>> that mu
>>> >> is the variable of interest, not x.
>>> >>
>>> >> Thanks in advance,
>>> >>
>>> >> Mike
>>> >>
>>> >> [[alternative HTML version deleted]]
>>> >>
>>> >> __
>>> >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> >> 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.
>>> >>
>>> >>
>>>
>>> [[alternative HTML version deleted]]
>>>
>>> __
>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> 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.
>>>
>>
>>
>
[[alternative HTML version deleted]]
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] How to use curve() function without using x as the variable name inside expression?
Hi Bill,
You solved by problem. For some reason, I thought xname was only referring
to name of the x-axis.
I remember last time I fixed it, it was something about xname, couldn't get
it right this time.
Thanks! Saved me hours from frustration.
Mike
On Thu, Jan 29, 2015 at 9:04 PM, William Dunlap wrote:
> Does
>help(curve)
> talk about its 'xname' argument?
>
> Try
>curve(10*foofoo, from=0, to=17, xname="foofoo")
>
> You will have to modify your function, since curve() will
> call it once with a long vector for the independent variable
> and func(rnorm(10), rnorm(10), mu=seq(0,5,len=501)) won't
> work right.
>
>
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
>
> On Thu, Jan 29, 2015 at 5:43 PM, C W wrote:
>
>> Hi Rui,
>>
>> Thank you for your help. That works for now, but eventually, I need to be
>> pass in x and y.
>>
>> Is there a way to tell the curve() function, x is a fix vector, mu is a
>> variable!
>>
>> Thanks,
>>
>> Mike
>>
>> On Thu, Jan 29, 2015 at 5:25 PM, Rui Barradas
>> wrote:
>>
>> > Hello,
>> >
>> > The following will work, but I don't know if it's what you want. func2
>> > will get x and y from the global environment.
>> >
>> > func2 <- function(mu){
>> >x + y + mu ^ 2
>> > }
>> >
>> > curve(func2, from = 0, to = 10)
>> >
>> >
>> > Hope this helps,
>> >
>> > Rui Barradas
>> >
>> > Em 29-01-2015 21:02, C W escreveu:
>> >
>> >> Hi all,
>> >>
>> >> I want to graph a curve as a function of mu, not x.
>> >>
>> >> Here's the R code:
>> >>
>> >> x <- rnorm(10)
>> >> y <- rnorm(10)
>> >>
>> >> func <- function(x, y, mu){
>> >> x + y + mu ^ 2
>> >> }
>> >>
>> >> curve(f = func(x = x, y = y, mu), from = 0, to = 10)
>> >> I know I can change variable mu to x, but is there a way to tell R
>> that mu
>> >> is the variable of interest, not x.
>> >>
>> >> Thanks in advance,
>> >>
>> >> Mike
>> >>
>> >> [[alternative HTML version deleted]]
>> >>
>> >> __
>> >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> >> 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.
>> >>
>> >>
>>
>> [[alternative HTML version deleted]]
>>
>> __
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>>
>
>
[[alternative HTML version deleted]]
__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] How to use curve() function without using x as the variable name inside expression?
Does
help(curve)
talk about its 'xname' argument?
Try
curve(10*foofoo, from=0, to=17, xname="foofoo")
You will have to modify your function, since curve() will
call it once with a long vector for the independent variable
and func(rnorm(10), rnorm(10), mu=seq(0,5,len=501)) won't
work right.
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Thu, Jan 29, 2015 at 5:43 PM, C W wrote:
> Hi Rui,
>
> Thank you for your help. That works for now, but eventually, I need to be
> pass in x and y.
>
> Is there a way to tell the curve() function, x is a fix vector, mu is a
> variable!
>
> Thanks,
>
> Mike
>
> On Thu, Jan 29, 2015 at 5:25 PM, Rui Barradas
> wrote:
>
> > Hello,
> >
> > The following will work, but I don't know if it's what you want. func2
> > will get x and y from the global environment.
> >
> > func2 <- function(mu){
> >x + y + mu ^ 2
> > }
> >
> > curve(func2, from = 0, to = 10)
> >
> >
> > Hope this helps,
> >
> > Rui Barradas
> >
> > Em 29-01-2015 21:02, C W escreveu:
> >
> >> Hi all,
> >>
> >> I want to graph a curve as a function of mu, not x.
> >>
> >> Here's the R code:
> >>
> >> x <- rnorm(10)
> >> y <- rnorm(10)
> >>
> >> func <- function(x, y, mu){
> >> x + y + mu ^ 2
> >> }
> >>
> >> curve(f = func(x = x, y = y, mu), from = 0, to = 10)
> >> I know I can change variable mu to x, but is there a way to tell R that
> mu
> >> is the variable of interest, not x.
> >>
> >> Thanks in advance,
> >>
> >> Mike
> >>
> >> [[alternative HTML version deleted]]
> >>
> >> __
> >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >> 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.
> >>
> >>
>
> [[alternative HTML version deleted]]
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] How to use curve() function without using x as the variable name inside expression?
Hi Rui,
Thank you for your help. That works for now, but eventually, I need to be
pass in x and y.
Is there a way to tell the curve() function, x is a fix vector, mu is a
variable!
Thanks,
Mike
On Thu, Jan 29, 2015 at 5:25 PM, Rui Barradas wrote:
> Hello,
>
> The following will work, but I don't know if it's what you want. func2
> will get x and y from the global environment.
>
> func2 <- function(mu){
>x + y + mu ^ 2
> }
>
> curve(func2, from = 0, to = 10)
>
>
> Hope this helps,
>
> Rui Barradas
>
> Em 29-01-2015 21:02, C W escreveu:
>
>> Hi all,
>>
>> I want to graph a curve as a function of mu, not x.
>>
>> Here's the R code:
>>
>> x <- rnorm(10)
>> y <- rnorm(10)
>>
>> func <- function(x, y, mu){
>> x + y + mu ^ 2
>> }
>>
>> curve(f = func(x = x, y = y, mu), from = 0, to = 10)
>> I know I can change variable mu to x, but is there a way to tell R that mu
>> is the variable of interest, not x.
>>
>> Thanks in advance,
>>
>> Mike
>>
>> [[alternative HTML version deleted]]
>>
>> __
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>>
>>
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] How to use curve() function without using x as the variable name inside expression?
Hello,
The following will work, but I don't know if it's what you want. func2
will get x and y from the global environment.
func2 <- function(mu){
x + y + mu ^ 2
}
curve(func2, from = 0, to = 10)
Hope this helps,
Rui Barradas
Em 29-01-2015 21:02, C W escreveu:
Hi all,
I want to graph a curve as a function of mu, not x.
Here's the R code:
x <- rnorm(10)
y <- rnorm(10)
func <- function(x, y, mu){
x + y + mu ^ 2
}
curve(f = func(x = x, y = y, mu), from = 0, to = 10)
I know I can change variable mu to x, but is there a way to tell R that mu
is the variable of interest, not x.
Thanks in advance,
Mike
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
[R] How to use curve() function without using x as the variable name inside expression?
Hi all,
I want to graph a curve as a function of mu, not x.
Here's the R code:
x <- rnorm(10)
y <- rnorm(10)
func <- function(x, y, mu){
x + y + mu ^ 2
}
curve(f = func(x = x, y = y, mu), from = 0, to = 10)
I know I can change variable mu to x, but is there a way to tell R that mu
is the variable of interest, not x.
Thanks in advance,
Mike
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