random123

ut_uniform.cpp (5947B)

---

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  /* ut_uniform.cpp:   unit test for uniform.hpp.  
 
     This is a "sanity test" of u01, uneg11 and u01fixedpt.  We confirm
     that a histogram of few thousand calls to each of the functions
     matches a reference histogram.  This verifies that the results are
     generally sane i.e., they fall within the expected range, and that
     they are close to a correct distribution.  It is *not* a foolproof
     test of correctness, but it should catch portability issues
     like errors in r123::make_signed or r123::make_unsigned
     or r123::maxTvalue or misunderstandings about std::numeric_limits.
 
     There is a "known answer test" for uniform.hpp in ut_uniform_IEEEkat.cpp,
     but it is only expected to work on machines with strict IEEE arithmetic
     and  no high-precicision intermediates.  See its own comments for
     more details.
  */
 
 #include <Random123/uniform.hpp>
 #include <Random123/threefry.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <map>
 #include <string>
 #include <sstream>
 
 using namespace r123;
 
 template <typename T>
 typename r123::make_unsigned<T>::type U(T x){ return x; }
 
 template <typename T>
 typename r123::make_signed<T>::type S(T x){ return x; }
         
 #define Chk(u, Rng, Ftype) do{                            \
         chk<Ftype, Rng>(#u, #Rng, #Ftype, &u<Ftype, Rng::ctr_type::value_type>); \
     }while(0)
 
 std::map<std::string, std::string> refmap;
 
 void RefHist(const char* k, const char *v){
     refmap[std::string(k)] = std::string(v);
 }
 
 void fillrefhist(){
 #include "ut_uniform_reference.hpp"
 }
 
 bool checking = true;
 int nfail = 0;
 
 template<typename Ftype, typename RNG, typename Utype>
 void chk(const std::string& fname, const std::string& rngname, const std::string& ftypename, Utype f){
     std::string key = fname + " " + rngname + " " + ftypename;
     RNG rng;
     typedef typename RNG::ukey_type ukey_type;
     typedef typename RNG::ctr_type ctr_type;
     typedef typename RNG::key_type key_type;
 
     ctr_type c = {{}};
     ukey_type uk = {{}};
     key_type k = uk;
     // 26 bins - 13 greater than 0 and 13 less.  Why 13?  Because a
     // prime number seems less likely to tickle the rounding-related
     // corner cases, which is aruably both good and bad.
     const int NBINS=26;
     
     int hist[NBINS] = {};
     for(int i=0; i<1000; ++i){
         c = c.incr();
         ctr_type r = rng(c, k);
         for(int j=0; j<ctr_type::static_size; ++j){
             Ftype u = f(r[j]);
             //printf("%s %llx, %.17g\n", key.c_str(), (long long)r[j], (double)u);
             R123_ASSERT( u >= -1.);
             R123_ASSERT( u <= 1.);
             int idx = (int) ((u + Ftype(1.))*Ftype(NBINS/2));
             hist[idx]++;
         }
     }
     std::ostringstream oss;
     for(int i=0; i<NBINS; ++i){
         oss << " " << hist[i];
     }
     if(checking){
         if( oss.str() != refmap[key] ){
             printf("MISMATCH:  %s:\n\tcomputed histogram=%s\n\treference histogram=%s\n", 
                    key.c_str(),
                    oss.str().c_str(),
                    refmap[key].c_str());
             nfail++;
         }
     }else{
         printf("RefHist(\"%s\", \"%s\");\n",  key.c_str(), oss.str().c_str());
     }
 }
 
 int main(int argc, char **argv){
     checking = (argc==1);
     fillrefhist();
 
     // 18 tests:  3 functions (u01, uneg11, u01fixedpt)
     //          x 2 input sizes (32 bit or 64 bit)
     //          x 3 output sizes (float, double, long double)
     Chk(u01, Threefry4x32, float);
     Chk(u01, Threefry4x32, double);
     Chk(u01, Threefry4x32, long double);
 
 #if R123_USE_64BIT
     Chk(u01, Threefry4x64, float);
     Chk(u01, Threefry4x64, double);
     Chk(u01, Threefry4x64, long double);
 #endif
 
     Chk(uneg11, Threefry4x32, float);
     Chk(uneg11, Threefry4x32, double);
     Chk(uneg11, Threefry4x32, long double);
 
 #if R123_USE_64BIT
     Chk(uneg11, Threefry4x64, float);
     Chk(uneg11, Threefry4x64, double);
     Chk(uneg11, Threefry4x64, long double);
 #endif
     
     Chk(u01fixedpt, Threefry4x32, float);
     Chk(u01fixedpt, Threefry4x32, double);
     Chk(u01fixedpt, Threefry4x32, long double);
 
 #if R123_USE_64BIT
     Chk(u01fixedpt, Threefry4x64, float);
     Chk(u01fixedpt, Threefry4x64, double);
     Chk(u01fixedpt, Threefry4x64, long double);
 #endif
 
     if(nfail){
         printf("// %s: FAILED %d Known-Answer-Tests failed\n", argv[0], nfail);
     }else if(checking){
         printf("%s: SUCCESS\n", argv[0]);
     }
 
     return !!nfail;
 }