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formatting pass.

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This commit is contained in:
NunoSempere 2023-07-16 16:30:38 +02:00
parent 607554f22b
commit c487bdfaf5
1 changed files with 149 additions and 144 deletions
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87
scratchpad/scratchpad.c
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@ -1,9 +1,9 @@
#include <limits.h> // INT_MAX
#include <stdint.h>
#include <stdlib.h>
#include <float.h> // FLT_MAX, FLT_MIN #include <float.h> // FLT_MAX, FLT_MIN
#include <stdio.h> #include <limits.h> // INT_MAX
#include <math.h> // erf, sqrt #include <math.h> // erf, sqrt
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h> #include <time.h>
#define EXIT_ON_ERROR 0 #define EXIT_ON_ERROR 0
@ -12,7 +12,7 @@
struct box { struct box {
int empty; int empty;
float content; float content;
char * error_msg; char* error_msg;
}; };
// Example cdf // Example cdf
@ -76,10 +76,10 @@ struct box inverse_cdf(float cdf(float), float p)
} }
if (!interval_found) { if (!interval_found) {
if(EXIT_ON_ERROR){ if (EXIT_ON_ERROR) {
printf("Interval containing the target value not found, in function inverse_cdf, in %s (%d)", __FILE__, __LINE__); printf("Interval containing the target value not found, in function inverse_cdf, in %s (%d)", __FILE__, __LINE__);
exit(1); exit(1);
}else{ } else {
char error_msg[200]; char error_msg[200];
snprintf(error_msg, 200, "Interval containing the target value not found in function inverse_cdf, in %s (%d)", __FILE__, __LINE__); snprintf(error_msg, 200, "Interval containing the target value not found in function inverse_cdf, in %s (%d)", __FILE__, __LINE__);
result.empty = 1; result.empty = 1;
@ -114,10 +114,10 @@ struct box inverse_cdf(float cdf(float), float p)
result.content = low; result.content = low;
result.empty = 0; result.empty = 0;
} else { } else {
if(EXIT_ON_ERROR){ if (EXIT_ON_ERROR) {
printf("Search process did not converge, in function inverse_cdf, in %s (%d)", __FILE__, __LINE__); printf("Search process did not converge, in function inverse_cdf, in %s (%d)", __FILE__, __LINE__);
exit(1); exit(1);
}else{ } else {
char error_msg[200]; char error_msg[200];
snprintf(error_msg, 200, "Search process did not converge, in function inverse_cdf, in %s (%d)", __FILE__, __LINE__); snprintf(error_msg, 200, "Search process did not converge, in function inverse_cdf, in %s (%d)", __FILE__, __LINE__);
result.empty = 1; result.empty = 1;
@ -178,7 +178,8 @@ float sampler_normal_0_1(uint32_t* seed)
#define STOP 1.0e-8 #define STOP 1.0e-8
#define TINY 1.0e-30 #define TINY 1.0e-30
struct box incbeta(float a, float b, float x) { struct box incbeta(float a, float b, float x)
{
// Descended from <https://github.com/codeplea/incbeta/blob/master/incbeta.c>, // Descended from <https://github.com/codeplea/incbeta/blob/master/incbeta.c>,
// but modified to return a box struct and floats instead of doubles. // but modified to return a box struct and floats instead of doubles.
// [x] to do: add attribution in README // [x] to do: add attribution in README
@ -209,11 +210,11 @@ struct box incbeta(float a, float b, float x) {
*/ */
struct box result; struct box result;
if (x < 0.0 || x > 1.0){ if (x < 0.0 || x > 1.0) {
if(EXIT_ON_ERROR){ if (EXIT_ON_ERROR) {
printf("x = %f, x out of bounds [0, 1], 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); exit(1);
}else{ } else {
char error_msg[200]; char error_msg[200];
snprintf(error_msg, 200, "x = %f, x out of bounds [0, 1], in function incbeta, in %s (%d)", x, __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.empty = 1;
@ -223,60 +224,62 @@ struct box incbeta(float a, float b, float x) {
} }
/*The continued fraction converges nicely for x < (a+1)/(a+b+2)*/ /*The continued fraction converges nicely for x < (a+1)/(a+b+2)*/
if (x > (a+1.0)/(a+b+2.0)) { if (x > (a + 1.0) / (a + b + 2.0)) {
struct box symmetric_incbeta = incbeta(b,a,1.0-x); struct box symmetric_incbeta = incbeta(b, a, 1.0 - x);
if(symmetric_incbeta.empty){ if (symmetric_incbeta.empty) {
return symmetric_incbeta; // propagate error return symmetric_incbeta; // propagate error
}else{ } else {
result.empty = 0; result.empty = 0;
result.content = 1-symmetric_incbeta.content; result.content = 1 - symmetric_incbeta.content;
return result; return result;
} }
} }
/*Find the first part before the continued fraction.*/ /*Find the first part before the continued fraction.*/
const float lbeta_ab = lgamma(a)+lgamma(b)-lgamma(a+b); const float lbeta_ab = lgamma(a) + lgamma(b) - lgamma(a + b);
const float front = exp(log(x)*a+log(1.0-x)*b-lbeta_ab) / a; const float front = exp(log(x) * a + log(1.0 - x) * b - lbeta_ab) / a;
/*Use Lentz's algorithm to evaluate the continued fraction.*/ /*Use Lentz's algorithm to evaluate the continued fraction.*/
float f = 1.0, c = 1.0, d = 0.0; float f = 1.0, c = 1.0, d = 0.0;
int i, m; int i, m;
for (i = 0; i <= 200; ++i) { for (i = 0; i <= 200; ++i) {
m = i/2; m = i / 2;
float numerator; float numerator;
if (i == 0) { if (i == 0) {
numerator = 1.0; /*First numerator is 1.0.*/ numerator = 1.0; /*First numerator is 1.0.*/
} else if (i % 2 == 0) { } else if (i % 2 == 0) {
numerator = (m*(b-m)*x)/((a+2.0*m-1.0)*(a+2.0*m)); /*Even term.*/ numerator = (m * (b - m) * x) / ((a + 2.0 * m - 1.0) * (a + 2.0 * m)); /*Even term.*/
} else { } else {
numerator = -((a+m)*(a+b+m)*x)/((a+2.0*m)*(a+2.0*m+1)); /*Odd term.*/ numerator = -((a + m) * (a + b + m) * x) / ((a + 2.0 * m) * (a + 2.0 * m + 1)); /*Odd term.*/
} }
/*Do an iteration of Lentz's algorithm.*/ /*Do an iteration of Lentz's algorithm.*/
d = 1.0 + numerator * d; d = 1.0 + numerator * d;
if (fabs(d) < TINY) d = TINY; if (fabs(d) < TINY)
d = TINY;
d = 1.0 / d; d = 1.0 / d;
c = 1.0 + numerator / c; c = 1.0 + numerator / c;
if (fabs(c) < TINY) c = TINY; if (fabs(c) < TINY)
c = TINY;
const float cd = c*d; const float cd = c * d;
f *= cd; f *= cd;
/*Check for stop.*/ /*Check for stop.*/
if (fabs(1.0-cd) < STOP) { if (fabs(1.0 - cd) < STOP) {
result.content = front * (f-1.0); result.content = front * (f - 1.0);
result.empty = 0; result.empty = 0;
return result; return result;
} }
} }
if(EXIT_ON_ERROR){ if (EXIT_ON_ERROR) {
printf("More loops needed, did not converge, in function incbeta, in %s (%d)", __FILE__, __LINE__); printf("More loops needed, did not converge, in function incbeta, in %s (%d)", __FILE__, __LINE__);
exit(1); exit(1);
}else{ } else {
char error_msg[200]; char error_msg[200];
snprintf(error_msg, 200, "More loops needed, did not converge, in function incbeta, in %s (%d)", __FILE__, __LINE__); snprintf(error_msg, 200, "More loops needed, did not converge, in function incbeta, in %s (%d)", __FILE__, __LINE__);
result.empty = 1; result.empty = 1;
@ -285,20 +288,22 @@ struct box incbeta(float a, float b, float x) {
} }
} }
struct box cdf_beta(float x){ struct box cdf_beta(float x)
if(x < 0){ {
struct box result = { .empty = 0, .content = 0}; if (x < 0) {
struct box result = { .empty = 0, .content = 0 };
return result; return result;
} else if(x > 1){ } else if (x > 1) {
struct box result = { .empty = 0, .content = 1}; struct box result = { .empty = 0, .content = 1 };
return result; return result;
} else { } else {
float successes = 1, failures = (2023-1945); float successes = 1, failures = (2023 - 1945);
return incbeta(successes, failures, x); return incbeta(successes, failures, x);
} }
} }
float cdf_dangerous_beta(float x){ float cdf_dangerous_beta(float x)
{
// So the thing is, this works // So the thing is, this works
// But it will propagate through the code // But it will propagate through the code
// So it doesn't feel like a great architectural choice; // So it doesn't feel like a great architectural choice;
@ -313,18 +318,18 @@ float cdf_dangerous_beta(float x){
// b. clever & hacky go-to statements // b. clever & hacky go-to statements
// i. They actually look fun to implement // i. They actually look fun to implement
// ii. But they would be hard for others to use. // ii. But they would be hard for others to use.
if(x < 0){ if (x < 0) {
return 0; return 0;
} else if(x > 1){ } else if (x > 1) {
return 1; return 1;
} else { } else {
float successes = 100, failures = 100; float successes = 100, failures = 100;
struct box result = incbeta(successes, failures, x); struct box result = incbeta(successes, failures, x);
if(result.empty){ if (result.empty) {
printf("%s\n", result.error_msg); printf("%s\n", result.error_msg);
exit(1); exit(1);
return 1; return 1;
}else{ } else {
return result.content; return result.content;
} }
} }