[R] pchisq error

[Jeremy Silver]

oops. . . .  Turning it into a void function fixed the problem!

Thanks.

Jeremy


Thomas Lumley wrote:
>
> I don't get the error, but I assume it's because your C function
> returns a double and .C() assumes it is a void function.
>
>     -thomas
>
>
> On Mon, 19 Jan 2009, Jeremy Silver wrote:
>
>> Dear R experts,
>>
>> I'm trying to call 'pchisq' from within a C subroutine. The following
>> error is returned:
>>
>>   ** NON-convergence in pgamma()'s pd_lower_cf() f= nan.
>>
>> This error message is not printed the first time I call 'pchisq' from
>> the C subroutine, but the second time or the next time I call 'pchisq'
>> from within R.
>>
>> My session output is shown below:
>>
>> ######################
>>
>>> system('R CMD SHLIB reproduceError.c')
>>
>> make: `reproduceError.so' is up to date.
>>
>>>
>>
>>> reproduceError <- function(x){
>>
>> +   dyn.load('reproduceError.so')
>>
>> +   .C('tempCfunction',as.double(x))
>>
>> +   dyn.unload('reproduceError.so')
>>
>> +   invisible(NULL)
>>
>> + }
>>
>>>
>>
>>> pchisq(5.464342,1,lower.tail = FALSE)
>>
>> [1] 0.01940836
>>
>>> reproduceError(5.464342)
>>
>> stat = 5.464342, p = 0.019408
>>
>>> pchisq(5.464342,1,lower.tail = FALSE)
>>
>> [1] NaN
>>
>> Warning messages:
>>
>> 1: In pchisq(5.464342, 1, lower.tail = FALSE) :
>>
>>   ** NON-convergence in pgamma()'s pd_lower_cf() f= nan.
>>
>> 2: In pchisq(q, df, lower.tail, log.p) : NaNs produced
>>
>>> reproduceError(5.464342)
>>
>> stat = 5.464342, p = 0.019408
>>
>>> reproduceError(5.464342)
>>
>> stat = 5.464342, p = nan
>>
>> Warning message:
>>
>> In reproduceError(5.464342) :
>>
>>   ** NON-convergence in pgamma()'s pd_lower_cf() f= nan.
>>
>>> pchisq(5.464342,1,lower.tail = FALSE)
>>
>> [1] NaN
>>
>> Warning messages:
>>
>> 1: In pchisq(5.464342, 1, lower.tail = FALSE) :
>>
>>   ** NON-convergence in pgamma()'s pd_lower_cf() f= nan.
>>
>> 2: In pchisq(q, df, lower.tail, log.p) : NaNs produced
>>
>>> pchisq(5.464342,1,lower.tail = FALSE)
>>
>> [1] 0.01940836
>>
>>> pchisq(5.464342,1,lower.tail = FALSE)
>>
>> [1] 0.01940836
>>
>>>
>>
>>> sessionInfo()
>>
>> R version 2.8.0 (2008-10-20)
>>
>> i686-pc-linux-gnu
>>
>> locale:
>>
>> LC_CTYPE=en_US.UTF-8;LC_NUMERIC=C;LC_TIME=en_US.UTF-8;LC_COLLATE=en_US.UTF-8;LC_MONETARY=C;LC_MESSAGES=en_US.UTF-8;LC_PAPER=en_US.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US.UTF-8;LC_IDENTIFICATION=C
>>
>>
>> attached base packages:
>>
>> [1] stats     graphics  grDevices utils     datasets  methods   base
>>
>> #############################
>>
>>
>> The C file (reproduceError.c) with the subroutine tempCfunction is:
>>
>> #############################
>>
>> #include <stdio.h>
>>
>> #include <Rmath.h>
>>
>> #include <R.h>
>>
>> #include <Rinternals.h>
>>
>> #include <string.h>
>>
>> double tempCfunction(double *x){
>>
>>  double stat = x[0];
>>
>>  double pval = pchisq(stat, 1.0 , 0, 0);
>>
>>  printf("stat = %f, p = %f\n",stat,pval);
>>
>>
>>
>>  return pval;
>>
>> }
>>
>> #############################
>>
>> Can anybody explain this behaviour?
>>
>> Thanks,
>>
>> Jeremy
>>
>> -- 
>> /****************************************
>> Jeremy Silver
>> Research Assistant
>> University of Copenhagen, Denmark
>> ph: +45 3532 7917
>> email: j.silver at biostat.ku.dk or jere at pubhealth.ku.dk
>>
>> ______________________________________________
>> 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.
>>
>
> Thomas Lumley            Assoc. Professor, Biostatistics
> tlumley at u.washington.edu    University of Washington, Seattle
>
>