squiggle.c

commit 607554f22b67531c8b0e75cf3611257b9bfbc18f
parent e94774ae3aa05fe84470cb092d256b18fd42e464
Author: NunoSempere <nuno.sempere@protonmail.com>
Date:   Sun, 16 Jul 2023 14:38:12 +0200

add beta distribution samples!!

Diffstat:
M
scratchpad/scratchpad
 | 
0

M
scratchpad/scratchpad.c
 | 
68
+++++++++++++++++++++++++++++++++++++++++++++++++++-----------------

2 files changed, 51 insertions(+), 17 deletions(-)
diff --git a/scratchpad/scratchpad b/scratchpad/scratchpad
Binary files differ.
diff --git a/scratchpad/scratchpad.c b/scratchpad/scratchpad.c
@@ -211,11 +211,11 @@ struct box incbeta(float a, float b, float x) {
 
     if (x < 0.0 || x > 1.0){ 
 			  if(EXIT_ON_ERROR){
-					printf("x out of bounds, in function incbeta, in %s (%d)", __FILE__, __LINE__);
+					printf("x = %f, x out of bounds [0, 1], in function incbeta, in %s (%d)", __FILE__, __LINE__);
 					exit(1);
 				}else{
 					char error_msg[200];
-					snprintf(error_msg, 200, "x out of bounds, in function incbeta, in %s (%d)", __FILE__, __LINE__);
+					snprintf(error_msg, 200, "x = %f, x out of bounds [0, 1], in function incbeta, in %s (%d)", x, __FILE__, __LINE__);
 					result.empty = 1;
 					result.error_msg = error_msg;
 					return result;
@@ -286,8 +286,16 @@ struct box incbeta(float a, float b, float x) {
 }
 
 struct box cdf_beta(float x){
-	float successes = 1, failures = (2023-1945);
-	return incbeta(successes, failures, x);
+	if(x < 0){
+		struct box result = { .empty = 0, .content = 0};
+		return result;
+	} else if(x > 1){
+		struct box result = { .empty = 0, .content = 1};
+		return result;
+	} else {
+	  float successes = 1, failures = (2023-1945);
+	  return incbeta(successes, failures, x);
+	}
 }
 
 float cdf_dangerous_beta(float x){
@@ -295,20 +303,32 @@ float cdf_dangerous_beta(float x){
 	// But it will propagate through the code
 	// So it doesn't feel like a great architectural choice;
 	// I prefer my choice of setting a variable which will determine whether to exit on failure or not.
-	float successes = 1, failures = (2023-1945);
-	struct box result =  incbeta(successes, failures, x);
-	if(result.empty){
-		printf("%s", result.error_msg);
-		exit(1);
-	}else{
-		return result.content;
+	// Ok, so the proper thing to do would be to refactor inverse_cdf
+	// but, I could also use a GOTO? <https://stackoverflow.com/questions/245742/examples-of-good-gotos-in-c-or-c>
+	// Ok, alternatives are:
+	// - Refactor inverse_cdf to take a box, take the small complexity + penalty. Add a helper 
+	// - Duplicate the code, have a refactored inverse_cdf as well as a normal cdf
+	// - Do something hacky
+	//   a. dangerous beta, which exits
+	//   b. clever & hacky go-to statements
+	//     i. They actually look fun to implement
+	//     ii. But they would be hard for others to use.
+	if(x < 0){
+		return 0;
+	} else if(x > 1){
+		return 1;
+	} else {
+		float successes = 100, failures = 100;
+		struct box result =  incbeta(successes, failures, x);
+		if(result.empty){
+			printf("%s\n", result.error_msg);
+			exit(1);
+			return 1;
+		}else{
+			return result.content;
+		}
 	}
 }
-struct box dangerous_beta_sampler(uint32_t* seed)
-	// Think through what to do to feed the incbeta box into 
-{
-  return sampler(cdf_dangerous_beta, seed);
-}
 
 int main()
 {
@@ -373,6 +393,20 @@ int main()
 		clock_t end_2 = clock();
 		float time_spent_2 = (float)(end_2 - begin_2) / CLOCKS_PER_SEC;
 		printf("Time spent: %f", time_spent_2);
-
+		
+		// Get some beta samples
+		clock_t begin_3 = clock();
+    printf("\n\nGetting some samples from box sampler_dangerous_beta\n");
+    for (int i = 0; i < n; i++) {
+        struct box sample = sampler(cdf_dangerous_beta, seed);
+        if (sample.empty) {
+            printf("Error in sampler function");
+        } else {
+            printf("%f\n", sample.content);
+        }
+    }
+		clock_t end_3 = clock();
+		float time_spent_3 = (float)(end_3 - begin_3) / CLOCKS_PER_SEC;
+		printf("Time spent: %f", time_spent_3);
     return 0;
 }