add parallelism to sampling

README.md

@@ -308,7 +308,7 @@ Overall, I'd describe the error handling capabilities of this library as pretty
 
 ## To do list
 
-- [ ] Write better confidence interval code that:
+- [x] Write better confidence interval code that:
   - Gets number of samples as an input
   - Gets either a sampler function or a list of samples
   - is O(n), not O(nlog(n))

squiggle_more.c

@@ -115,9 +115,10 @@ ci array_get_90_ci(double xs[], int n)
 ci sampler_get_ci(ci interval, double (*sampler)(uint64_t*), int n, uint64_t* seed)
 {
     double* xs = malloc(n * sizeof(double));
-    for (int i = 0; i < n; i++) {
+    /*for (int i = 0; i < n; i++) {
         xs[i] = sampler(seed);
-    }
+    }*/
+    sampler_parallel(sampler, xs, 16, n);
     ci result = array_get_ci(interval, xs, n);
     free(xs);
     return result;