Fix density of Dirichlet distribution

4ment · 4ment · commit 5b198a52c70c · 2024-07-11T06:42:00.000+10:00
diff --git a/src/phyc/dirichlet.c b/src/phyc/dirichlet.c
@@ -23,7 +23,7 @@ double ddirchletln( const double *x, const size_t dim, const double *alphas ){
     double logp = 0;
     double sum = 0;
     for (size_t i = 0; i < dim; i++) {
-        logp += alphas[i]-1.0 + log(x[i]) - gammln(alphas[i]);;
+        logp += (alphas[i]-1.0) * log(x[i]) - gammln(alphas[i]);
 		sum += alphas[i];
     }
     logp += gammln(sum);

Original file line number	Diff line number	Diff line change
`@@ -23,7 +23,7 @@ double ddirchletln( const double x, const size_t dim, const double alphas ){`
`23`	`23`	`double logp = 0;`
`24`	`24`	`double sum = 0;`
`25`	`25`	`for (size_t i = 0; i < dim; i++) {`
`26`		`- logp += alphas[i]-1.0 + log(x[i]) - gammln(alphas[i]);;`
	`26`	`+ logp += (alphas[i]-1.0) * log(x[i]) - gammln(alphas[i]);`
`27`	`27`	`sum += alphas[i];`
`28`	`28`	`}`
`29`	`29`	`logp += gammln(sum);`