I want to generate a set of unit vectors (for any arbitrary dimension), which are evenly distributed across all directions. For this I generate normally distributed numbers for each vector component and scale the result by the inverse of the magnitude.
My question: Can I use a single std::default_random_engine
to generate numbers for all components of my vector or does every component require its own engine?
Afaik, each component needs to be Gaussian-distributed independently for the math to work out and I cannot assess the difference between the two scenarios. Here's a MWE with a single RNG (allocation and normalization of vectors is omitted here).
std::vector<std::vector<double>> GenerateUnitVecs(size_t dimension, size_t count)
{
std::vector<std::vector<double>> result;
/* Set up a _single_ RNG */
size_t seed = GetSeed(); // system_clock
std::default_random_engine gen(seed);
std::normal_distribution<double> distribution(0.0, 1.0);
/* Generate _multiple_ (independent?) distributions */
for(size_t ii = 0; ii < count; ++ii){
std::vector<double> vec;
for(size_t comp = 0; comp < dimension; ++comp)
vec.push_back(distribution(gen)); // <-- random number goes here
result.push_back(vec);
}
return result;
}
Thank you.
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