[R] Where to find the source codes for the internal function in stats package

[Murray Cooper]

Dear Dr Murdoch,

I understand in principle your explanation, but specifically where in the
source distribution are these functions found? For instance, I would like
to look at the code for model.matrix. Ex:
    ans <- .Internal(model.matrix(t, data))

I have looked at the source distribution but been unable to locate the
file which contains model.matrix.

Thanks for your help.

Murray Cooper

----- Original Message ----- 
From: "Duncan Murdoch" <murdoch at stats.uwo.ca>
To: "zhijie zhang" <rusers.sh at gmail.com>
Cc: <r-help at stat.math.ethz.ch>
Sent: Saturday, January 17, 2009 6:00 AM
Subject: Re: [R] Where to find the source codes for the internal function in 
stats package


> On 17/01/2009 2:23 AM, zhijie zhang wrote:
>> Dear all,
>>   I want to see the source codes for "dchisq(x, df, ncp=0, log = FALSE)",
>> but cannot find it.
>> I input "dchisq" in the R interface, and then enter, the following 
>> message
>> return:
>>> dchisq
>> /*****************************************************/
>> function (x, df, ncp = 0, log = FALSE)
>> {
>>     if (missing(ncp))
>>         .Internal(dchisq(x, df, log))
>>     else .Internal(dnchisq(x, df, ncp, log))
>> }
>> <environment: namespace:stats>
>> /*****************************************************/
>>  It seems that dchisq() is the internal function in STATS package. So go
>> to "C:\Program Files\R\R-2.7.2\library\stats" to look for it. I browsed 
>> the
>> files in this catalog, but it seems that i missed it.
>> Anybody can tell me how and where to find the codes, Thanks a lot.
>
> Uwe Ligges wrote a nice article on finding source in R News :
>
>   Ligges, U. (2006): R Help Desk: Accessing the Sources. R News 6 (4), 
> 43-45. http://cran.r-project.org/doc/Rnews/
>
> As it explains, .Internal() calls functions in the main R binary, not in a 
> package DLL.
>
> Duncan Murdoch
>
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