From 1521030421af2e8734ff6721881f348e2f0f9bb9 Mon Sep 17 00:00:00 2001
From: NunoSempere <nuno.sempere@protonmail.com>
Date: Sun, 19 Nov 2023 15:50:21 +0000
Subject: [PATCH] tweak parallize function

---
 .../core/03_gcc_nested_function/example.c     |  1 +
 squiggle_more.c                               | 56 +++++++++----------
 squiggle_more.h                               |  2 +
 3 files changed, 30 insertions(+), 29 deletions(-)

diff --git a/examples/core/03_gcc_nested_function/example.c b/examples/core/03_gcc_nested_function/example.c
index dbf9821..c8facb0 100644
--- a/examples/core/03_gcc_nested_function/example.c
+++ b/examples/core/03_gcc_nested_function/example.c
@@ -15,6 +15,7 @@ int main()
 
     int n_dists = 4;
 
+    // These are nested functions. They will not compile without gcc.
     double sample_0(uint64_t * seed) { return 0; }
     double sample_1(uint64_t * seed) { return 1; }
     double sample_few(uint64_t * seed) { return sample_to(1, 3, seed); }
diff --git a/squiggle_more.c b/squiggle_more.c
index e670be2..f8e7bcc 100644
--- a/squiggle_more.c
+++ b/squiggle_more.c
@@ -7,20 +7,20 @@
 #include <stdlib.h>
 #include "squiggle.h"
 
-// math constants
+/* Math constants */
 #define PI 3.14159265358979323846 // M_PI in gcc gnu99
 #define NORMAL90CONFIDENCE 1.6448536269514727
 
-// Some error niceties; these won't be used until later
+/* Some error niceties */
+// These won't be used until later 
 #define MAX_ERROR_LENGTH 500
 #define EXIT_ON_ERROR 0
 #define PROCESS_ERROR(error_msg) process_error(error_msg, EXIT_ON_ERROR, __FILE__, __LINE__)
 
-// Get confidence intervals, given a sampler
+/* Get confidence intervals, given a sampler */
 // Not in core yet because I'm not sure how much I like the struct
 // and the built-in 100k samples
 // to do: add n to function parameters and document
-
 typedef struct ci_t {
     float low;
     float high;
@@ -58,7 +58,10 @@ ci get_90_confidence_interval(double (*sampler)(uint64_t*), uint64_t* seed)
     return result;
 }
 
-// ## Sample from an arbitrary cdf
+/* Scaffolding to handle errors */
+// We are building towards sample from an arbitrary cdf
+// and that operation might fail
+// so we build some scaffolding here
 struct box {
     int empty;
     double content;
@@ -78,14 +81,10 @@ struct box process_error(const char* error_msg, int should_exit, char* file, int
     }
 }
 
-// Inverse cdf at point
-// Two versions of this function:
-//   - raw, dealing with cdfs that return doubles
-//     - input: cdf: double => double, p
-//     - output: Box(number|error)
-//   - box, dealing with cdfs that return a box.
-//     - input: cdf: double => Box(number|error), p
-//     - output: Box(number|error)
+/* Invert an arbitrary cdf at a point */
+// Version #1:
+// - input: (cdf: double => double, p)
+// - output: Box(number|error)
 struct box inverse_cdf_double(double cdf(double), double p)
 {
     // given a cdf: [-Inf, Inf] => [0,1]
@@ -149,6 +148,9 @@ struct box inverse_cdf_double(double cdf(double), double p)
     }
 }
 
+// Version #2: 
+// - input: (cdf: double => Box(number|error), p)
+// - output: Box(number|error)
 struct box inverse_cdf_box(struct box cdf_box(double), double p)
 {
     // given a cdf: [-Inf, Inf] => Box([0,1])
@@ -225,7 +227,9 @@ struct box inverse_cdf_box(struct box cdf_box(double), double p)
     }
 }
 
-// Sampler based on inverse cdf and randomness function
+/* Sample from an arbitrary cdf */
+// Before: invert an arbitrary cdf at a point
+// Now: from an arbitrary cdf, get a sample
 struct box sampler_cdf_box(struct box cdf(double), uint64_t* seed)
 {
     double p = sample_unit_uniform(seed);
@@ -238,22 +242,18 @@ struct box sampler_cdf_double(double cdf(double), uint64_t* seed)
     struct box result = inverse_cdf_double(cdf, p);
     return result;
 }
-
-/* Could also define other variations, e.g.,
-double sampler_danger(struct box cdf(double), uint64_t* seed)
+double sampler_cdf_danger(struct box cdf(double), uint64_t* seed)
 {
     double p = sample_unit_uniform(seed);
     struct box result = inverse_cdf_box(cdf, p);
-		if(result.empty){
-			exit(1);
-		}else{
-			return result.content;
-		}
+	if(result.empty){
+	    exit(1);
+	}else{
+		return result.content;
+	}
 }
-*/
-
-// # Small algebra manipulations
 
+/* Algebra manipulations */
 // here I discover named structs,
 // which mean that I don't have to be typing
 // struct blah all the time.
@@ -304,9 +304,8 @@ ci convert_lognormal_params_to_ci(lognormal_params y)
     return result;
 }
 
-// Paralellism
-/*
-void paralellize(float (*sampler)(uint64_t* seed), float* results, int n_threads, int n_samples){
+/* Parallel sampler */
+void parallel_sampler(double (*sampler)(uint64_t* seed), double* results, int n_threads, int n_samples){
     if((n_samples % n_threads) != 0){
         fprintf(stderr, "Number of samples isn't divisible by number of threads, aborting\n");
         exit(1);
@@ -336,4 +335,3 @@ void paralellize(float (*sampler)(uint64_t* seed), float* results, int n_threads
     }
     free(seeds);
 }
-*/
diff --git a/squiggle_more.h b/squiggle_more.h
index b71ae4f..70bb07c 100644
--- a/squiggle_more.h
+++ b/squiggle_more.h
@@ -46,4 +46,6 @@ lognormal_params algebra_product_lognormals(lognormal_params a, lognormal_params
 lognormal_params convert_ci_to_lognormal_params(ci x);
 ci               convert_lognormal_params_to_ci(lognormal_params y);
 
+void parallel_sampler(double (*sampler)(uint64_t* seed), double* results, int n_threads, int n_samples);
+
 #endif