[Rcpp-devel] Rcpp: Error: not compatible with requested type

[Dirk Eddelbuettel]

Hi Pierre,

On 3 October 2014 at 18:19, Pierre Lafaye de Micheaux wrote:
| Dear Dirk,
| 
| Thank you very much for this. I modified slightly your own code so that 
| it is very similar (for the names of the arguments) to the one on 
| StackOverflow:
| http://stackoverflow.com/questions/26181068/rcpp-error-not-compatible-with-requested-type
| 
| This gives me this code saved in /tmp/pierre.cpp:
| 
| -----------------------------------------------------------------------------------------------
| #include <Rcpp.h>
| 
| // [[Rcpp::export]]
| Rcpp::List gensampleRcpp2(Rcpp::Function rlawfunc, Rcpp::IntegerVector n) {
|    Rcpp::RNGScope __rngScope;
     ^^^^^^^^^^^^^^^^^^^^^^^^^^

Not needed. Rcpp Attributes adds that for your, and better.

|    return Rcpp::List::create(Rcpp::Named("sample") = rlawfunc(n),
|                              Rcpp::Named("law.name") = " ",
|                              Rcpp::Named("law.pars") = R_NilValue);
| }
| 
| // [[Rcpp::export]]
| Rcpp::List compQuantRcpp2(Rcpp::IntegerVector n, Rcpp::IntegerVector M, 
| Rcpp::Function Rlaw) {
|    int i;
|    GetRNGstate();

Not needed. Rcpp Attributes deals with that via RNGScope. 

|    for (i=1;i<=M[0];i++) {
|      Rcpp::List resultsample = gensampleRcpp2(Rlaw, n);
|      Rcpp::NumericVector mysample = resultsample["sample"];
|    }
|     PutRNGstate();

Ditto.

So try without, and for kicks add   verbose=TRUE  to the call to sourceCpp().

|     return Rcpp::List::create(Rcpp::Named("law.pars") = "");
| }
| 
| 
| /*** R
| res <- compQuantRcpp2(n=50, M=10^3, Rlaw=rnorm)
| print(str(res))
| */
| -----------------------------------------------------------------------------------------------
| 
| Please have a look to compare both codes. They are very similar.
| 
| I then issue this command in R:
| for (i in 1:100)  Rcpp::sourceCpp("tmp/pierre.cpp")
| 
| Magic! No error occur.
| 
| So now I will try to implement all this in a package (I guess I should 
| read more carefully the Attributes vignette that you told me about. Am I 
| right? Is it the good document to read for that purpose?).
| 
| By the way, since both codes are such similar, would you have an 
| explanation on what goes wrong with what I have written on StackOverflow?

I don't have time to drill through it function by function. The gist of it is
that you were doing A LOT of forced manual conversions, and one of them goes
bad.  If you really want to know, add prints statements (or step through) and
simplify.  

What you sent, even after your numerous prior emails was still not a
__minimally__ reproducible example.

The more complex the code is that you submit, the less likely it is
volunteers will spend _their_ going through it for you.

Dirk
 
| Regards,
| 
| Pierre L.
| 
| 
| 
| Le 03/10/2014 12:49, Dirk Eddelbuettel a écrit :
| > Oh, and I missed one call to a subordinate function.  So add
| >
| > // [[Rcpp::export]]
| > SEXP newCompQuant2(int n, int M, Rcpp::Function f) {
| >    SEXP res = compquantRcpp2(n, M, f);
| >    return res;
| > }
| >
| > and at the bottom call it:
| >
| > res <- newCompQuant2(n=50, M=10^3, f=rnorm)
| > print(str(res))
| >
| > and then the result is
| >
| > R> res <- newCompQuant2(n=50, M=10^3, f=rnorm)
| >
| > R> print(str(res))
| > List of 1
| >   $ law.pars: chr ""
| > NULL
| > R>
| >
| > just like you were told as well on StackOverflow.
| >
| > Dirk
| >
| 
| _______________________________________________
| Rcpp-devel mailing list
| Rcpp-devel at lists.r-forge.r-project.org
| https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel

-- 
http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org