On Fri, 17 Jan 2020 13:55:39 +0000 وليد خلف معوض المطيرى <wkmtie...@qu.edu.sa> wrote:

> So, does anyone have an idea of how to solve this issue. "Writing R Extensions", 1.6. Writing portable packages: >> Compiled code should not call the system random number generators >> such as rand, drand48 and random, but rather use the interfaces to >> R’s RNGs described in Random numbers. In particular, if more than >> one package initializes the system RNG (e.g. via srand), they will >> interfere with each other. >> Nor should the C++11 random number library be used, nor any other >> third-party random number generators such as those in GSL. It somewhat less convenient to call the R random number generator from Fortran than it would be from C or C++, but still possible. There is a F77-style example of such use [1], but since you are already using iso_c_binding, you should be able to declare the C API [2] right in the Fortran source: subroutine GetRNGState() bind(c) end subroutine subroutine PutRNGstate() bind(c) end subroutine As a bonus, you get to use the R distribution functions [3], without the need to implement them yourself from uniformly distributed samples: function rnorm(mu, sigma) bind(c) result(ret) use intrinsic, iso_c_binding, only: c_double real(c_double), value :: mu, sigma real(c_double) ret end function function rgamma(shape, scale) bind(c) result(ret) use intrinsic, iso_c_binding, only: c_double real(c_double), value :: shape, scale real(c_double) ret end function (The prototypes above are unchecked; I haven't written any Fortran 2003 in more than a year.) -- Best regards, Ivan [1]: https://cran.r-project.org/doc/manuals/R-exts.html#index-Random-numbers-in-Fortran [2]: https://cran.r-project.org/doc/manuals/R-exts.html#Random-numbers [3]: https://cran.r-project.org/doc/manuals/R-exts.html#Distribution-functions ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel