formatting pass, upkeep

This commit is contained in:
NunoSempere 2024-01-20 14:30:20 +01:00
parent 199e76bdfb
commit 1d89eb6231
5 changed files with 68 additions and 61 deletions

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@ -15,8 +15,16 @@ int main()
int n_dists = 4;
// These are nested functions. They will not compile without gcc.
double sample_0(uint64_t * seed) { UNUSED(seed); return 0; }
double sample_1(uint64_t * seed) { UNUSED(seed); return 1; }
double sample_0(uint64_t * seed)
{
UNUSED(seed);
return 0;
}
double sample_1(uint64_t * seed)
{
UNUSED(seed);
return 1;
}
double sample_few(uint64_t * seed) { return sample_to(1, 3, seed); }
double sample_many(uint64_t * seed) { return sample_to(2, 10, seed); }

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@ -1,11 +1,11 @@
#include "../squiggle.h"
// #include "../squiggle_more.h"
#include "../../../squiggle.h"
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
double sample_loguniform(double a, double b, uint64_t* seed){
double sample_loguniform(double a, double b, uint64_t* seed)
{
return exp(sample_uniform(log(a), log(b), seed));
}
@ -16,10 +16,11 @@ int main()
// set randomness seed
uint64_t* seed = malloc(sizeof(uint64_t));
*seed = UINT64_MAX/64; // xorshift can't start with a seed of 0
double sample_fermi_naive(uint64_t* seed){
double rate_of_star_formation = sample_loguniform(1,100, seed);
*seed = UINT64_MAX / 64; // xorshift can't start with a seed of 0
double sample_fermi_naive(uint64_t * seed)
{
double rate_of_star_formation = sample_loguniform(1, 100, seed);
double fraction_of_stars_with_planets = sample_loguniform(0.1, 1, seed);
double number_of_habitable_planets_per_star_system = sample_loguniform(0.1, 1, seed);
double rate_of_life_formation_in_habitable_planets = sample_lognormal(1, 50, seed);
@ -41,34 +42,29 @@ int main()
// Expected number of civilizations in the Milky way;
// see footnote 3 (p. 5)
double n = rate_of_star_formation *
fraction_of_stars_with_planets *
number_of_habitable_planets_per_star_system *
fraction_of_habitable_planets_in_which_any_life_appears *
fraction_of_planets_with_life_in_which_intelligent_life_appears *
fraction_of_intelligent_planets_which_are_detectable_as_such *
longevity_of_detectable_civilizations;
double n = rate_of_star_formation * fraction_of_stars_with_planets * number_of_habitable_planets_per_star_system * fraction_of_habitable_planets_in_which_any_life_appears * fraction_of_planets_with_life_in_which_intelligent_life_appears * fraction_of_intelligent_planets_which_are_detectable_as_such * longevity_of_detectable_civilizations;
return n;
}
double sample_fermi_paradox_naive(uint64_t* seed){
double sample_fermi_paradox_naive(uint64_t * seed)
{
double n = sample_fermi_naive(seed);
return ((n > 1) ? 1 : 0);
}
double n = 1000000;
double naive_fermi_proportion = 0;
for(int i=0; i<n; i++){
for (int i = 0; i < n; i++) {
double result = sample_fermi_paradox_naive(seed);
// printf("result: %lf\n", result);
naive_fermi_proportion+=result;
naive_fermi_proportion += result;
}
printf("Naïve %% that we are not alone: %lf\n", naive_fermi_proportion/n);
printf("Naïve %% that we are not alone: %lf\n", naive_fermi_proportion / n);
// Thinking in log space
double sample_fermi_logspace(uint64_t* seed){
double sample_fermi_logspace(uint64_t * seed)
{
double log_rate_of_star_formation = sample_uniform(log(1), log(100), seed);
double log_fraction_of_stars_with_planets = sample_uniform(log(0.1), log(1), seed);
double log_number_of_habitable_planets_per_star_system = sample_uniform(log(0.1), log(1), seed);
@ -83,13 +79,7 @@ int main()
// printf(" log_fraction_of_intelligent_planets_which_are_detectable_as_such = %lf\n", log_fraction_of_intelligent_planets_which_are_detectable_as_such);
// printf(" log_longevity_of_detectable_civilizations = %lf\n", log_longevity_of_detectable_civilizations);
double log_n1 =
log_rate_of_star_formation +
log_fraction_of_stars_with_planets +
log_number_of_habitable_planets_per_star_system +
log_fraction_of_planets_with_life_in_which_intelligent_life_appears +
log_fraction_of_intelligent_planets_which_are_detectable_as_such +
log_longevity_of_detectable_civilizations;
double log_n1 = log_rate_of_star_formation + log_fraction_of_stars_with_planets + log_number_of_habitable_planets_per_star_system + log_fraction_of_planets_with_life_in_which_intelligent_life_appears + log_fraction_of_intelligent_planets_which_are_detectable_as_such + log_longevity_of_detectable_civilizations;
// printf("first part of calculation: %lf\n", log_n1);
/* Consider fraction_of_habitable_planets_in_which_any_life_appears separately.
@ -125,9 +115,9 @@ int main()
// printf("log_rate_of_life_formation_in_habitable_planets: %lf\n", log_rate_of_life_formation_in_habitable_planets);
double log_fraction_of_habitable_planets_in_which_any_life_appears;
if(log_rate_of_life_formation_in_habitable_planets < -32){
if (log_rate_of_life_formation_in_habitable_planets < -32) {
log_fraction_of_habitable_planets_in_which_any_life_appears = log_rate_of_life_formation_in_habitable_planets;
} else{
} else {
double rate_of_life_formation_in_habitable_planets = exp(log_rate_of_life_formation_in_habitable_planets);
double fraction_of_habitable_planets_in_which_any_life_appears = -expm1(-rate_of_life_formation_in_habitable_planets);
log_fraction_of_habitable_planets_in_which_any_life_appears = log(fraction_of_habitable_planets_in_which_any_life_appears);
@ -139,19 +129,19 @@ int main()
return log_n;
}
double sample_fermi_paradox_logspace(uint64_t* seed){
double sample_fermi_paradox_logspace(uint64_t * seed)
{
double n = sample_fermi_logspace(seed);
return ((n > 0) ? 1 : 0);
}
double logspace_fermi_proportion = 0;
for(int i=0; i<n; i++){
for (int i = 0; i < n; i++) {
double result = sample_fermi_paradox_logspace(seed);
// printf("result: %lf\n", result);
logspace_fermi_proportion+=result;
logspace_fermi_proportion += result;
}
printf("Using more accurate logspace computations, %% that we are not alone: %lf\n", logspace_fermi_proportion/n);
double result2;
printf("Using more accurate logspace computations, %% that we are not alone: %lf\n", logspace_fermi_proportion / n);
free(seed);
}

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@ -1,5 +1,5 @@
#include "../squiggle.h"
#include "../squiggle_more.h"
// #include "../squiggle_more.h"
#include <math.h>
#include <stdint.h>
#include <stdio.h>
@ -7,16 +7,18 @@
double sample_loguniform(double a, double b, uint64_t* seed){
return exp(sample_uniform(log(a), log(b), seed));
}
int main()
{
// Replicate <https://arxiv.org/pdf/1806.02404.pdf>, and in particular the red line in page 11.
// Could also be interesting to just produce and save many samples.
// set randomness seed
uint64_t* seed = malloc(sizeof(uint64_t));
*seed = UINT64_MAX/64; // xorshift can't start with a seed of 0
double fermi_naive(uint64_t* seed){
double sample_fermi_naive(uint64_t* seed){
double rate_of_star_formation = sample_loguniform(1,100, seed);
double fraction_of_stars_with_planets = sample_loguniform(0.1, 1, seed);
double number_of_habitable_planets_per_star_system = sample_loguniform(0.1, 1, seed);
@ -50,21 +52,23 @@ int main()
return n;
}
double fermi_paradox_naive(uint64_t* seed){
double n = fermi_naive(seed);
return (n > 1 ? 1 : 0);
double sample_fermi_paradox_naive(uint64_t* seed){
double n = sample_fermi_naive(seed);
return ((n > 1) ? 1 : 0);
}
double result;
for(int i=0; i<1000; i++){
result = fermi_naive(seed);
printf("result from fermi_naive: %lf\n", result);
printf("\n\n");
double n = 1000000;
double naive_fermi_proportion = 0;
for(int i=0; i<n; i++){
double result = sample_fermi_paradox_naive(seed);
// printf("result: %lf\n", result);
naive_fermi_proportion+=result;
}
printf("result from naïve implementation: %lf\n", result);
printf("Naïve %% that we are not alone: %lf\n", naive_fermi_proportion/n);
// Thinking in log space
double fermi_logspace(uint64_t* seed){
double sample_fermi_logspace(uint64_t* seed){
double log_rate_of_star_formation = sample_uniform(log(1), log(100), seed);
double log_fraction_of_stars_with_planets = sample_uniform(log(0.1), log(1), seed);
double log_number_of_habitable_planets_per_star_system = sample_uniform(log(0.1), log(1), seed);
@ -86,7 +90,7 @@ int main()
log_fraction_of_planets_with_life_in_which_intelligent_life_appears +
log_fraction_of_intelligent_planets_which_are_detectable_as_such +
log_longevity_of_detectable_civilizations;
printf("first part of calculation: %lf\n", log_n1);
// printf("first part of calculation: %lf\n", log_n1);
/* Consider fraction_of_habitable_planets_in_which_any_life_appears separately.
Imprecisely, we could do:
@ -110,14 +114,15 @@ int main()
Turns out there is!
Looking at the Taylor expansion for c = 1 - exp(-b), it's b - b^2/2 + b^3/6 - x^b/24, etc.
When b ~ 0 (as it is), this is close to b.
// https://www.wolframalpha.com/input?i=1-exp%28-x%29
When b ~ 0 (as is often the case), this is close to b.
But now, if b ~ 0
c ~ b
and d = log(c) ~ log(b) = log(exp(a)) = a
*/
double log_rate_of_life_formation_in_habitable_planets = sample_normal(1, 50, seed);
printf("log_rate_of_life_formation_in_habitable_planets: %lf\n", log_rate_of_life_formation_in_habitable_planets);
// printf("log_rate_of_life_formation_in_habitable_planets: %lf\n", log_rate_of_life_formation_in_habitable_planets);
double log_fraction_of_habitable_planets_in_which_any_life_appears;
if(log_rate_of_life_formation_in_habitable_planets < -32){
@ -127,22 +132,26 @@ int main()
double fraction_of_habitable_planets_in_which_any_life_appears = -expm1(-rate_of_life_formation_in_habitable_planets);
log_fraction_of_habitable_planets_in_which_any_life_appears = log(fraction_of_habitable_planets_in_which_any_life_appears);
}
printf(" log_fraction_of_habitable_planets_in_which_any_life_appears: %lf\n", log_fraction_of_habitable_planets_in_which_any_life_appears);
// printf(" log_fraction_of_habitable_planets_in_which_any_life_appears: %lf\n", log_fraction_of_habitable_planets_in_which_any_life_appears);
double log_n = log_n1 + log_fraction_of_habitable_planets_in_which_any_life_appears;
return log_n;
}
double result2;
/*
for(int i=0; i<1000; i++){
result2 = fermi_logspace(seed);
printf("result from logspace implementation: %lf.2\n", result2);
printf("\n\n");
double sample_fermi_paradox_logspace(uint64_t* seed){
double n = sample_fermi_logspace(seed);
return ((n > 0) ? 1 : 0);
}
*/
double logspace_fermi_proportion = 0;
for(int i=0; i<n; i++){
double result = sample_fermi_paradox_logspace(seed);
// printf("result: %lf\n", result);
logspace_fermi_proportion+=result;
}
printf("Using more accurate logspace computations, %% that we are not alone: %lf\n", logspace_fermi_proportion/n);
double result2;
free(seed);
}