squiggle.c

commit 015d33adca87d305784402ce89b0b75821878a5b
parent fa714f91ae0a49eefc0232513c82d9a40ebb80c1
Author: NunoSempere <nuno.sempere@protonmail.com>
Date:   Wed, 27 Sep 2023 13:51:05 +0100

reword comments

Diffstat:
M
squiggle.c
 | 
9
+++------

1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/squiggle.c b/squiggle.c
@@ -22,13 +22,10 @@
 // Pseudo Random number generator
 uint64_t xorshift32(uint32_t* seed)
 {
-    // The reader isn't expected to understand this code immediately;
-    // read the linked Wikipedia page!
     // Algorithm "xor" from p. 4 of Marsaglia, "Xorshift RNGs"
     // See <https://stackoverflow.com/questions/53886131/how-does-xorshift32-works>
     // https://en.wikipedia.org/wiki/Xorshift
     // Also some drama: <https://www.pcg-random.org/posts/on-vignas-pcg-critique.html>, <https://prng.di.unimi.it/>
-    // for floats
     uint64_t x = *seed;
     x ^= x << 13;
     x ^= x >> 17;
@@ -38,7 +35,7 @@ uint64_t xorshift32(uint32_t* seed)
 
 uint64_t xorshift64(uint64_t* seed)
 {
-    // same as above, but for generating doubles
+    // same as above, but for generating doubles instead of floats
     uint64_t x = *seed;
     x ^= x << 13;
     x ^= x >> 7;
@@ -79,7 +76,7 @@ double sample_lognormal(double logmean, double logstd, uint64_t* seed)
     return exp(sample_normal(logmean, logstd, seed));
 }
 
-inline double sample_normal_from_95_confidence_interval(double low, double high, uint64_t* seed)
+inline double sample_normal_from_90_confidence_interval(double low, double high, uint64_t* seed)
 {
     // Explanation of key idea:
     // 1. We know that the 90% confidence interval of the unit normal is
@@ -112,7 +109,7 @@ double sample_to(double low, double high, uint64_t* seed)
     // Then see code for sample_normal_from_95_confidence_interval
     double loglow = logf(low);
     double loghigh = logf(high);
-    return exp(sample_normal_from_95_confidence_interval(loglow, loghigh, seed));
+    return exp(sample_normal_from_90_confidence_interval(loglow, loghigh, seed));
 }
 
 double sample_gamma(double alpha, uint64_t* seed)