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small reorg, comment purpose of functions

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NunoSempere 2023-07-22 19:24:00 +02:00
parent 04070a934e
commit 36249ebf39
1 changed files with 6 additions and 0 deletions
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squiggle.c
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@ -28,6 +28,7 @@ uint32_t xorshift32(uint32_t* seed)
} }
// Distribution & sampling functions // Distribution & sampling functions
// Unit distributions
float sample_unit_uniform(uint32_t* seed) float sample_unit_uniform(uint32_t* seed)
{ {
// samples uniform from [0,1] interval. // samples uniform from [0,1] interval.
@ -43,11 +44,13 @@ float sample_unit_normal(uint32_t* seed)
return z; return z;
} }
// Composite distributions
float sample_uniform(float from, float to, uint32_t* seed) float sample_uniform(float from, float to, uint32_t* seed)
{ {
return sample_unit_uniform(seed) * (to - from) + from; return sample_unit_uniform(seed) * (to - from) + from;
} }
float sample_normal(float mean, float sigma, uint32_t* seed) float sample_normal(float mean, float sigma, uint32_t* seed)
{ {
return (mean + sigma * sample_unit_normal(seed)); return (mean + sigma * sample_unit_normal(seed));
@ -60,6 +63,9 @@ float sample_lognormal(float logmean, float logsigma, uint32_t* seed)
float sample_to(float low, float high, uint32_t* seed) float sample_to(float low, float high, uint32_t* seed)
{ {
// Given a (positive) 90% confidence interval,
// returns a sample from a lognormal
// with a matching 90% c.i.
const float NORMAL95CONFIDENCE = 1.6448536269514722; const float NORMAL95CONFIDENCE = 1.6448536269514722;
float loglow = logf(low); float loglow = logf(low);
float loghigh = logf(high); float loghigh = logf(high);