<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Hi, I ran the same code on all systems: main () {   double i, j, k;   mpq_t rat;     printf("hi\n");   mpq_init(rat);   mpq_set_ui(rat, 4, 5);   k = mpq_get_d(rat);   printf("rat is %.17f\n", k);   } and I built from the same GMP source. The version of gcc used for each build is different: 32 bit Linux                     gcc 3.2.3 MinGW 32 bit Windows    gcc 3.4.1 MinGW 64 bit Windows    gcc 4.4.0 Does the version of gcc makes a difference? The Linux version was the only one I was able to run make check on (and it passed, as far as I can tell), because the others were all cross-compiled. Is this a known issue for GMP 4.2.2 on Linux? Is there anyway I can avoid it -- I would like to use the same version of GMP for all platforms if possible. Cheers, Kish --- On Tue, 3/17/09, Sisyphus <sisyphus1@optusnet.com.au> wrote: <blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;">From: Sisyphus <sisyphus1@optusnet.com.au> Subject: Re: mpq_get_d() rounding for different platforms? To: "K Shen" <kishshen@yahoo.com>, gmp-discuss@gmplib.org Date: Tuesday, March 17, 2009, 10:56 AM <pre>----- Original Message ----- From: "K Shen" <kishshen@yahoo.com> > For example, for the rational 4/5, > > the MinGW version returns 0.79999999999999993, while the Linux version > returns 0.80000000000000004. Make sure that the assignment of 4/5 is being carried out in the same way. As the following little program demonstrates, mpq_set_str(q, "4/5", 10) and mpq_set_d(q, (double) 4 / 5) assigm different values: ############################# #include <stdio.h> #include <gmp.h> int main(void) { mpq_t q1; mpq_t q2; mpq_init(q1); mpq_init(q2); mpq_set_str(q1, "4/5", 10); mpq_set_d(q2, (double)4 / 5); printf("%.17f\n", mpq_get_d(q1)); printf("%.17f\n", mpq_get_d(q2)); mpq_clear(q1); mpq_clear(q2); return 0; } ############################# For me (both Linux and MinGW) that outputs: 0.79999999999999993 0.80000000000000004 Cheers, Rob </pre></blockquote></td></tr></table>