On 09/02/2015 01:35 PM, Marcus Müller wrote:
I'd say we rather want better
randomness than faster noise sources
If that's the case, I'd recommend that Stefan uses the
normal_distribution variate from boost (Stefan, see my example), rather
than doing his own "normalization" of the RV, and we use that.
Regarding Boost's mt19937 and the ways Stefan and I make normal
distributed RV out of the uint32_t that this emits:
From getting "raw" uniform uint32_t instead of normal floats through
boost's normal_distribution(rng) variate is that, to little surprise,
75% of time is spent looking up/interpolating/calculating based on the
uniform integers to normally distributed floats. Blind guess is that
this would be something that someone who really cares about speed might
implement in VOLK with sufficient accuracy, making WGN generation
X3x0-capable.
Cheers,
Marcus
A call to SHA-256 can return 256 bytes at a time.... Map those bytes
into {-1.0,1.0}. That may still not be fast enough, dunno. But the
distribution
should be good.
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