[R] Converting a function from Splus to R
R. Michael Weylandt
michael.weylandt at gmail.com
Wed Feb 29 15:07:55 CET 2012
Oh...that does make more sense -- seemed like a rather odd choice of
variable name.
Michael
On Wed, Feb 29, 2012 at 8:40 AM, Prof Brian Ripley
<ripley at stats.ox.ac.uk> wrote:
> On 29/02/2012 13:24, R. Michael Weylandt wrote:
>>
>> Change the name to something syntactically valid? The problem is that
>> you can't (well, you can, but it's ill advised) have variable names
>> beginning with numbers. They don't seem to be used much so there
>> won't be much trouble in that.
>
>
> I think that 2.0d0 is someone translating C into R. Just use 2 . In R, 2 is
> a double precision floating-point constant: in C and (recent S-PLUS) it is
> integer and you need to use 2.0 .
>
>> Michael
>>
>> 2012/2/29 Freddy Hernández<fhernanb at gmail.com>:
>>>
>>> I have a function written for Splus, when I run it in R I obtain get an
>>> error
>>> because the function has the elements "0.d0" and "2.d0". How can I change
>>> it
>>> to run in R?
>>>
>>> The function can be found in page 230 from
>>> http://www.stat.wisc.edu/~mchung/teaching/stat471/stat_computing.pdf
>>>
>>> Function is as follows:
>>>
>>> gauher<- function(n) {# Gauss-Hermite: returns x,w so that
>>> #\int_-\infty^\infty exp(-x^2) f(x) dx \doteq \sum w_i f(x_i)
>>> EPS<- 3.e-14
>>> PIM4<- .7511255444649425D0
>>> MAXIT<- 10
>>> m<- trunc((n+1)/2)
>>> x<- w<- rep(-1,n)
>>> for (i in 1:m) {
>>> if (i==1) {
>>> z<- sqrt(2*n+1)-1.85575*(2*n+1)^(-.16667)
>>> } else if(i==2) {
>>> z<- z-1.14*n^.426/z
>>> } else if (i==3) {
>>> z<- 1.86*z-.86*x[1]
>>> } else if (i==4) {
>>> z<- 1.91*z-.91*x[2]
>>> } else {
>>> z<- 2.*z-x[i-2]
>>> }
>>> for (its in 1:MAXIT) {
>>> p1<- PIM4
>>> p2<- 0.d0
>>> for (j in 1:n) {
>>> p3<- p2
>>> p2<- p1
>>> p1<- z*sqrt(2.d0/j)*p2-sqrt((j-1)/j)*p3
>>> }
>>> pp<- sqrt(2.d0*n)*p2
>>> z1<- z
>>> z<- z1-p1/pp
>>> if(abs(z-z1)<= EPS) break
>>> }
>>> x[i]<- z
>>> x[n+1-i]<- -z
>>> w[i]<- 2/(pp*pp)
>>> w[n+1-i]<- w[i]
>>> }
>>> list(x=x,w=w)
>>> }
>>>
>>> --
>>> View this message in context:
>>> http://r.789695.n4.nabble.com/Converting-a-function-from-Splus-to-R-tp4431416p4431416.html
>>> Sent from the R help mailing list archive at Nabble.com.
>>>
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>>
>>
>> ______________________________________________
>> 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.
>
>
>
> --
> Brian D. Ripley, ripley at stats.ox.ac.uk
> Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
> University of Oxford, Tel: +44 1865 272861 (self)
> 1 South Parks Road, +44 1865 272866 (PA)
> Oxford OX1 3TG, UK Fax: +44 1865 272595
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