Mercurial > octave
diff libinterp/corefcn/rand.cc @ 17258:213ee68b59da
Handle out-of-range values consistently when initializing random number generator.
* oct-rand.cc: New function double2uint32(). It normalizes a finite double by
taking it modulo 2^32, such that the result is in [0, 2^32). Nonfinites give
zero as result. This prevents compiler-dependent casting of a double whose
truncated value cannot be represented in a uint32_t.
* rand.cc: Add %!test block to verify behavior.
| author | Philipp Kutin <philipp.kutin@gmail.com> |
|---|---|
| date | Thu, 15 Aug 2013 20:14:30 +0200 |
| parents | 2fc554ffbc28 |
| children | bc924baa2c4e |
line wrap: on
line diff
--- a/libinterp/corefcn/rand.cc Thu Aug 15 14:17:20 2013 -0700 +++ b/libinterp/corefcn/rand.cc Thu Aug 15 20:14:30 2013 +0200 @@ -533,6 +533,19 @@ %! endif */ +/* +%!# Test out-of-range values as rand() seeds. See oct-rand.cc: double2uint32(). +%!function v = __rand_sample__ (initval) +%! rand ("state", initval); +%! v = rand (1, 6); +%!endfunction +%! +%!assert (__rand_sample__ (0), __rand_sample__ (2^32)) +%!assert (__rand_sample__ (-2), __rand_sample__ (2^32-2)) +%!assert (__rand_sample__ (Inf), __rand_sample__ (NaN)) +%!assert (! isequal (__rand_sample__ (-1), __rand_sample__ (-2))) +*/ + static std::string current_distribution = octave_rand::distribution (); DEFUN (randn, args, ,