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add more examples, tweak code a bit

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NunoSempere 2023-07-16 12:09:41 +02:00
parent c7d9f87ad7
commit 4deb2044d6
2 changed files with 37 additions and 15 deletions
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@ -6,8 +6,6 @@
#include <math.h>
#define VERBOSE 1
// to do: reuse more informative printing from build-your-own-lisp
// Errors
// https://mccue.dev/pages/7-27-22-c-errors
// Huh, first time I've really needed a struct
@ -17,6 +15,7 @@
// options:
// - exit
// - pass structs
// to do: reuse more informative printing from build-your-own-lisp?
struct box {
int empty;
float content;
@ -93,12 +92,10 @@ struct box inverse_cdf(float cdf(float), float p){
int convergence_condition = 0;
int count = 0;
while(!convergence_condition && (count < (INT_MAX/2) )){
if(VERBOSE){
printf("while loop\n");
}
float mid = (high + low)/2;
int mid_not_new = (mid == low) || (mid == high);
if(VERBOSE){
if(0){
printf("while loop\n");
printf("low: %f, high: %f\n", low, high);
printf("mid: %f\n", mid);
}
@ -161,32 +158,57 @@ struct box sampler(float cdf(float), uint32_t* seed){
return result;
}
// to-do: integrals => beta distribution
// ~~[-] to-do: integrals => beta distribution~~
// => instead, use this incomplete beta function implementation, based on continuous fractions:
// <https://codeplea.com/incomplete-beta-function-c>
// <https://github.com/codeplea/incbeta>
// main with an example
int main(){
// Uniform:
struct box result = inverse_cdf(cdf_uniform_0_1, 0.5);
if(result.empty){
printf("Inverse not calculated\n");
struct box result_1 = inverse_cdf(cdf_uniform_0_1, 0.5);
char* name_1 = "cdf_uniform_0_1";
if(result_1.empty){
printf("Inverse for %s not calculated\n", name_1);
exit(1);
}else{
printf("Inverse of the cdf at %f is: %f\n", 0.5, result.content);
printf("Inverse of %s at %f is: %f\n", name_1, 0.5, result_1.content);
}
// Squared cdf
struct box result2 = inverse_cdf(cdf_squared_0_1, 0.5);
if(result2.empty){
printf("Inverse not calculated\n");
struct box result_2 = inverse_cdf(cdf_squared_0_1, 0.5);
char* name_2 = "cdf_squared_0_1";
if(result_2.empty){
printf("Inverse for %s not calculated\n", name_2);
exit(1);
}else{
printf("Inverse of the cdf at %f is: %f\n", 0.5, result2.content);
printf("Inverse of %s at %f is: %f\n", name_2, 0.5, result_2.content);
}
// Normal cdf
struct box result_3 = inverse_cdf(cdf_normal_0_1, 0.5);
char* name_3 = "cdf_normal_0_1";
if(result_3.empty){
printf("Inverse for %s not calculated\n", name_3);
exit(1);
}else{
printf("Inverse of %s at %f is: %f\n", name_3, 0.5, result_3.content);
}
// set randomness seed
uint32_t* seed = malloc(sizeof(uint32_t));
*seed = 1000; // xorshift can't start with 0
printf("\n\nGetting some samples from %s:\n", name_3);
int n=100;
for(int i=0;i<n; i++){
struct box sample = sampler(cdf_normal_0_1, seed);
if(sample.empty){
printf("Error in sampler function");
}else{
printf("%f\n", sample.content);
}
}
return 0;
}