M.van_Iterson at lumc.nl
2016-Mar-10 11:47 UTC
[Rd] rmultinom.c error probability not sum to 1
Dear all, I have a questions regarding using the c function rmultinom.c. I got the following error message "rbinom: probability sum should be 1, but is 0.999264" Which is thrown by: if(fabs((double)(p_tot - 1.)) > 1e-7) MATHLIB_ERROR(_("rbinom: probability sum should be 1, but is %g"), (double) p_tot); I understand my probabilities do not sum to one close enough. I tried the following, p[2] = 1. - p[0] - p[1], where 'p', are the probabilities but this is not sufficient to pass the error message! Thanks in advance! Regards, Maarten (I don't think this is an issue with versions but I used R version 3.2.3 and can provide more details on my linux build if necessary.) [[alternative HTML version deleted]]
On 10 Mar 2016, at 12:47 , M.van_Iterson at lumc.nl wrote:> Dear all, > > I have a questions regarding using the c function rmultinom.c. > > I got the following error message "rbinom: probability sum should be 1, but is 0.999264" > > Which is thrown by: > > if(fabs((double)(p_tot - 1.)) > 1e-7) > MATHLIB_ERROR(_("rbinom: probability sum should be 1, but is %g"), > (double) p_tot); > > I understand my probabilities do not sum to one close enough. I tried the following, > p[2] = 1. - p[0] - p[1], where 'p', are the probabilities but this is not sufficient to pass the error message! >p[0] ????> Thanks in advance! > > Regards, > Maarten > > (I don't think this is an issue with versions but I used R version 3.2.3 and can provide more details on my linux build if necessary.) > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel-- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
M.van_Iterson at lumc.nl
2016-Mar-10 20:25 UTC
[Rd] rmultinom.c error probability not sum to 1
Hi all, I should have given a better explanation of my problem. Here it is. I extracted from my code the bit that gives the error. Place this in a file called test.c #include <math.h> #include <R.h> #include <Rmath.h> #include <float.h> #include <R_ext/Print.h> int main(){ double prob[3] = {0.0, 0.0, 0.0}; double prob_tot = 0.; prob[0] = 0.3*dnorm(2, 0, 1, 0); prob[1] = 0.5*dnorm(5, 0, 1, 0); prob[2] = 0.2*dnorm(-3, 0, 1, 0); //obtain prob_tot prob_tot = 0.; for(int j = 0; j < 3; j++) prob_tot += prob[j]; //normalize probabilities for(int j = 0; j < 3; j++) prob[j] = prob[j]/prob_tot; //or this give the same error //prob[2] = 1.0 - prob[1] - prob[0]; //checking indeed prob_tot not exactly 1 for(int j = 0; j < 3; j++) prob_tot += prob[j]; Rprintf("Prob_tot: %f\n", prob_tot); int rN[3]; rmultinom(1, prob, 1, rN); return 0; } run R CMD SHLIB test.c to generate the test.so. Now from within R> dyn.load("test.so") > .C("main")Prob_tot: 1.017084 Error: rbinom: probability sum should be 1, but is 0.948075 Maybe I miss some trivial C knowledge why this is not exactly one! Thanks in advance! Regards, Maarten ________________________________________ From: peter dalgaard [pdalgd at gmail.com] Sent: Thursday, March 10, 2016 1:26 PM To: Iterson, M. van (MOLEPI) Cc: r-devel at r-project.org Subject: Re: [Rd] rmultinom.c error probability not sum to 1 On 10 Mar 2016, at 12:47 , M.van_Iterson at lumc.nl wrote:> Dear all, > > I have a questions regarding using the c function rmultinom.c. > > I got the following error message "rbinom: probability sum should be 1, but is 0.999264" > > Which is thrown by: > > if(fabs((double)(p_tot - 1.)) > 1e-7) > MATHLIB_ERROR(_("rbinom: probability sum should be 1, but is %g"), > (double) p_tot); > > I understand my probabilities do not sum to one close enough. I tried the following, > p[2] = 1. - p[0] - p[1], where 'p', are the probabilities but this is not sufficient to pass the error message! >p[0] ????> Thanks in advance! > > Regards, > Maarten > > (I don't think this is an issue with versions but I used R version 3.2.3 and can provide more details on my linux build if necessary.) > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel-- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
Maybe Matching Threads
- rmultinom.c error probability not sum to 1
- rmultinom.c error probability not sum to 1
- rmultinom.c error probability not sum to 1
- Error message for infinite probability parameters in rbinom() and rmultinom()
- Error message for infinite probability parameters in rbinom() and rmultinom()