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[Rcpp-devel] not sure if it's a rcpp question or a cpp question

Dirk Eddelbuettel
On 14 March 2013 at 14:42, Aileen Lin wrote:
| My C code:
| //[[Rcpp::depends("Rcpp")]]
| #include <Rcpp.h>
| #include <iostream>
| using namespace Rcpp;
| ?
| //[[Rcpp::export]]
| NumericVector sigmutest(double pd, double rsq){
| ? double qpd = R::qnorm(pd, 0, 1, 1, 0);
| ? double sgtemp = 0.2;
| ? double sg = 0.3;
| ? double eor = 1;
| ?
| ? double w = 0;
| ? while (eor>=0.0001) {?
| ??????? sg = sgtemp;
| ??????? w = pd * 0.4 / (R::pnorm((qpd - sqrt(rsq) * (-0.42) * sgtemp),
| 0, 1, 1, 0));
| ??????? sgtemp = (-0.5) * w + 0.4;
| ??????? std::cout << "sg " << sg << std::endl;
| ??????? std::cout << "sgtemp " << sgtemp << std::endl;
| ??????? eor = abs(sg - sgtemp);
| ???????
| ??????? std::cout << "error " << eor << std::endl;
| ???????
| ????? }
| ? NumericVector out(3);
| ? out(0) = sg;
| ? out(1) = sgtemp;
| ? out(2) = eor;
| ? return out;?
| }
| 
| My R code:
| 
| > Rcpp::sourceCpp('src/sbi.cpp')
| > x <- sigmutest(0.0002327279, 0.1025499338)
| sg 0.2
| sgtemp 0.219135
| error 0
| 
| ?
| Does anyone know what is going on? Thanks.

abs() is a C function for int-on-int. So eor becomes 0. 

Use std::fabs() instead.

Dirk

| --
| Aileen L.
| 
| View my Linkedin profile:?http://au.linkedin.com/in/aileen2
| 
| 
| Being happy doesn't mean you're perfect. It just means you've decided to look
| beyond the imperfections-?K.B Indiana (age 14)
| 
| 
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Thread (3 messages)

Aileen Lin not sure if it's a rcpp question or a cpp question Mar 13 Dirk Eddelbuettel not sure if it's a rcpp question or a cpp question Mar 13 Alon Honig not sure if it's a rcpp question or a cpp question Mar 13