formatting pass, upkeep

examples/core/03_gcc_nested_function/example.c

@@ -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); }
 

examples/core/06_dissolving_fermi_paradox/example.c

@@ -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));
 }
 
@@ -18,7 +18,8 @@ int main()
     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 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);
@@ -41,18 +42,13 @@ 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);
     }
@@ -66,9 +62,9 @@ int main()
     }
     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.
@@ -139,7 +129,8 @@ 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);
     }
@@ -151,7 +142,6 @@ int main()
         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);
 }

scratchpad/scratchpad.c

@@ -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);
 }