From dbe69ddaf5c60d63213aee1edb04ff679c18b4cb Mon Sep 17 00:00:00 2001
From: Aki Vehtari <Aki.Vehtari@aalto.fi>
Date: Wed, 15 Nov 2017 16:07:40 -0500
Subject: [PATCH] bug fix rng k->0

---
 demos_rstan/gpareto_functions/gpareto.stan | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/demos_rstan/gpareto_functions/gpareto.stan b/demos_rstan/gpareto_functions/gpareto.stan
index 8922998..5d56e4c 100644
--- a/demos_rstan/gpareto_functions/gpareto.stan
+++ b/demos_rstan/gpareto_functions/gpareto.stan
@@ -53,9 +53,9 @@ functions {
     if (sigma<=0)
       reject("sigma<=0; found sigma =", sigma)
     if (fabs(k) > 1e-15)
-      return (ymin + (pow(uniform_rng(0,1),-k)-1)*sigma/k);
+      return ymin + (uniform_rng(0,1)^-k -1) * sigma / k;
     else
-      return (ymin - sigma*log(1/uniform_rng(0,1)-1)); // limit k->0
+      return ymin - sigma*log(uniform_rng(0,1)); // limit k->0
   }
 }
 data {
@@ -66,8 +66,7 @@ data {
   vector<lower=ymin>[Nt] yt;
 }
 transformed data {
-  real ymax;
-  ymax = max(y);
+  real ymax = max(y);
 }
 parameters {
   real<lower=0> sigma;