From - Mon Jan 18 13:46:45 1999 From: zaykin@statgen.ncsu.edu (Dmitri Zaykin) Newsgroups: sci.math.num-analysis,sci.stat.math,sci.math Subject: Re: Random numbers for C: Improvements. Supersedes: <790f18msk.fsf@poole.statgen.ncsu.edu> Date: 18 Jan 1999 00:16:24 GMT Organization: Statistical Genetics dwnoon@compuserve.com (David W. Noon) writes: > The only other language I know of that has sufficiently powerful macro > facilities to force inlining like C but with better syntax, is > portable across many platforms, and produces efficient object code is > PL/I. If anybody besides me can use such code, I will produce it > too/instead. Another option is to re-write macros as C++ member functions. If all the code is in the body of the class or "inline" keyword is explicitly given, the compiler will attempt to inline the functions. Below is my version of it and an example of usage. I've put "//" comments in places where I thought changes to the C code are necessary. There are additional advantages over C-macros. (1) No global variables are introduced. (2) It is easy to run several "independent" random sequences by creating several variables of Rnd type and seeding them differently (something that would not be straightforward to do in C). Dmitri #include // ULONG_MAX and UCHAR_MAX defined there class Rnd { Rnd() {} typedef unsigned long Unlo; Unlo z, w, jsr, jcong, t[UCHAR_MAX+1], x, y; unsigned char c; Unlo znew() { return (z = 36969UL*(z & 65535UL)+(z >> 16)); } // +UL Unlo wnew() { return (w = 18000UL*(w & 65535UL)+(w >> 16)); } // +UL public: Rnd (Unlo i1, Unlo i2, Unlo i3, Unlo i4) : z(i1), w(i2), jsr(i3), jcong(i4), x(0), y(0), c(0) { for(int i=0; i>13))^(jsr<<5) jsr=jsr^(jsr<<17); jsr=jsr^(jsr>>13); return (jsr=jsr^(jsr<<5)); } Unlo Cong() { return (jcong = 69069UL*jcong + 1234567UL); } // +UL Unlo Kiss() { return (Mwc() ^ Cong()) + Shr3(); } Unlo Swb () { // was: t[c+237]=(x=t[c+15])-(y=t[c]+(x #include int main() { unsigned i, seed=time(0); Rnd rn (seed, 2*seed, 3*seed, 4*seed); for(i=0; i<5; i++) cout << rn(5) << endl; // [0, 1, 2, 3, 4] for(i=0; i<5; i++) cout << rn() << endl; // (0, ..., 1) for(i=0; i<5; i++) cout << rn.Vni() << endl; // (-1, ..., 1) for(i=0; i<5; i++) cout << rn(10, 20) << endl; // (10, ..., 20) for(i=0; i<5; i++) cout << rn.Lfib4() << endl; // trying Lfib4 for(i=0; i<5; i++) cout << rn.Swb() << endl; // trying Swb } ----------------------------------------------------------------------------- From - Thu Jan 21 15:28:34 1999 From: zaykin@statgen.ncsu.edu (Dmitri Zaykin) Newsgroups: sci.stat.math,sci.math,sci.math.num-analysis Subject: Re: Random numbers for C: Improvements. Date: 21 Jan 1999 04:40:53 GMT Organization: Statistical Genetics To check if C-macros for these random number generators do indeed always produce faster, and maybe "less bloated" code than inlined C++ member functions, I did a little experiment with timing/code size using the GNU compiler (egcs-1.1.1 g++/gcc) on Solaris 2.5.1. With this compiler, it is clearly not the case. (1) Executable size (conclusion: C++ code smaller) inlined member functions C-macros C-macros g++ -Winline -O2 -s g++ -Winline -O2 -s gcc -Winline -O2 -s 8908 9820 9532 (2) Timing in 10 experiments (conclusion: C++ code faster) inlined member functions C-macros C-macros g++ -Winline -O2 -s g++ -Winline -O2 -s gcc -Winline -O2 -s 11330000 15030000 14500000 11330000 15040000 14470000 11340000 15030000 14490000 11340000 15040000 14520000 11340000 15030000 14500000 11320000 15030000 14490000 11340000 15040000 14480000 11340000 15030000 14510000 11340000 15030000 14500000 11340000 15030000 14500000 //----------------------------------------------------- // C++ code: #include #include #include class Rnd { Rnd() {} typedef unsigned long Unlo; typedef unsigned char Uc; Unlo z, w, jsr, jcong, t[UCHAR_MAX+1], x, y, a, b; unsigned char c; Unlo znew() { return (z = 36969UL*(z & 65535UL)+(z >> 16)); } Unlo wnew() { return (w = 18000UL*(w & 65535UL)+(w >> 16)); } public: Rnd (Unlo i1, Unlo i2, Unlo i3, Unlo i4, Unlo i5, Unlo i6) : z(i1), w(i2), jsr(i3), jcong(i4), x(0), y(0), a(i5), b(i6), c(0) { for(int i=0; i>13); return (jsr=jsr^(jsr<<5)); } Unlo Cong() { return (jcong = 69069UL*jcong + 1234567UL); } Unlo Kiss() { return (Mwc() ^ Cong()) + Shr3(); } Unlo Swb () { x = t[(Uc)(c+15)]; t[(Uc)(c+237)] = x - (y = t[(Uc)(c+1)] + (x < y)); return t[++c]; } Unlo Lfib4() { t[c]=t[c]+t[(Uc)(c+58)]+t[(Uc)(c+119)]+t[(Uc)(c+179)]; return t[++c]; } Unlo Fib() { b=a+b; return (a=b-a); } double Uni() { return Kiss() * 2.328306e-10; } double Vni() { return long(Kiss()) * 4.656613e-10; } double operator () () { return Uni(); } Unlo operator () (Unlo n) { return n == 1 ? 0 : Kiss() / (ULONG_MAX/n + 1); } double operator () (double Min, double Max) { return Min+Uni()*(Max-Min); } }; int main() { unsigned long i, xx=0, seed=time(0); long spent; Rnd rn (seed, 2*seed, 3*seed, 4*seed, 5*seed, 6*seed); spent=clock(); for(i=0; i<77777777; i++) xx += (rn.Kiss() + rn.Swb()); printf ("%ld \t", clock()-spent); printf("\n"); } /*****************************************************************/ /* C-macros */ #include #include #include #define znew (z=36969UL*(z&65535UL)+(z>>16)) #define wnew (w=18000UL*(w&65535UL)+(w>>16)) #define MWC ((znew<<16)+wnew ) #define SHR3 (jsr^=(jsr<<17), jsr^=(jsr>>13), jsr^=(jsr<<5)) #define CONG (jcong=69069UL*jcong+1234567UL) #define FIB ((b=a+b),(a=b-a)) #define KISS ((MWC^CONG)+SHR3) #define UC (unsigned char) #define LFIB4 (c++,t[c]=t[c]+t[UC(c+58)]+t[UC(c+119)]+t[UC(c+178)]) #define SWB (x = t[UC(c+15)], t[UC(c+237)] = x-(y=t[UC(c+1)]+(x