std::generate_canonical
From cppreference.com
Defined in header <random> | ||
template<class RealType, std::size_t Bits, class Generator > RealType generate_canonical( Generator& g ); | (since C++11) | |
Generates a random floating point number in range [0, 1).
To generate enough entropy, generate_canonical() will call g() exactly k times, where k = max(1, ⌈ b / log2 R ⌉) and
- b =std::min(Bits, std::size_t{std::numeric_limits<RealType>::digits}),
- R = g.max()- g.min()+1.
Contents |
[edit]Parameters
| g | - | generator to use to acquire entropy |
[edit]Return value
Floating point value in range [0, 1).
[edit]Exceptions
None except from those thrown by g.
[edit]Notes
Some existing implementations have a bug where they may occasionally return 1.0 if RealType is floatGCC #63176LLVM #18767MSVC STL #1074. This is LWG issue 2524.
[edit]Example
Produce random numbers with 10 bits of randomness: this may produce only k * R distinct values.
Run this code
#include <iostream>#include <random> int main(){std::random_device rd;std::mt19937 gen(rd());for(int n =0; n <10;++n)std::cout<< std::generate_canonical<double, 10>(gen)<<' ';std::cout<<'\n';}
Possible output:
0.208143 0.824147 0.0278604 0.343183 0.0173263 0.864057 0.647037 0.539467 0.0583497 0.609219
[edit]See also
(C++11) | produces real values evenly distributed across a range (class template) |
