You need to declare the drand48 function within your C source file. Either
#include <stdlib.h> or extern double drand48(void); [EMAIL PROTECTED] writes: > Hello > > I'm trying to use C random generator function drand48() which return > floating-point values, uniformly distributed over [0,1], > (http://www.opengroup.org/onlinepubs/007908799/xsh/drand48.html). When > values are returned to R, they are not in [0,1]. A simple C program > using drand48() gives values in [0,1] so I suppose there is a problem > (type definition ?) between C and R. Here are R and C function and an > example. > > > # R function > simulC <- function(n) > { > dyn.load("test.so") > simR <- runif(n) > simC <- .C("test", > as.integer(n), > res=double(n))$res > out <- list(simR=simR,simC=simC) > out > } > > // C function > void test(int *n,double *res) > { > int i; > for(i=0;i<*n;i++) {res[i] = drand48();} > } > > # Result of x <- simulC(5) > > x > $simR > [1] 0.398567942 0.866053345 0.332070718 0.535814830 0.473418784 > $simC > [1] -1222291199 211182456 1007036963 1254056690 -646279915 > > > Any help will be greatly appreciated, > S�bastien > > > > -- > S�bastien D�jean ~~~~~~~~~~~ > http://www.lsp.ups-tlse.fr/Fp/Dejean > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help -- Douglas Bates [EMAIL PROTECTED] Statistics Department 608/262-2598 University of Wisconsin - Madison http://www.stat.wisc.edu/~bates/ ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
