Fix Stan syntax error

Author: jgabry

vignettes/loo2-elpd.Rmd

@@ -43,7 +43,7 @@ data {
   int<lower=1> N;
   matrix[N,K] x;
   array[N] int y;
-  vector[N] offset;
+  vector[N] offset_; // offset is reserved keyword in Stan so use offset_
 
   real beta_prior_scale;
   real alpha_prior_scale;
@@ -53,14 +53,14 @@ parameters {
   real intercept;
 }
 model {
-  y ~ poisson(exp(x * beta + intercept + offset));
+  y ~ poisson(exp(x * beta + intercept + offset_));
   beta ~ normal(0,beta_prior_scale);
   intercept ~ normal(0,alpha_prior_scale);
 }
 generated quantities {
   vector[N] log_lik;
   for (n in 1:N)
-    log_lik[n] = poisson_lpmf(y[n] | exp(x[n] * beta + intercept + offset[n]));
+    log_lik[n] = poisson_lpmf(y[n] | exp(x[n] * beta + intercept + offset_[n]));
 }
 "
 ```
@@ -105,7 +105,7 @@ data_train <- list(y = roaches$y[roaches$test == 0],
                                          c("roach1", "treatment", "senior")]),
                    N = nrow(roaches[roaches$test == 0,]),
                    K = 3,
-                   offset = roaches$offset[roaches$test == 0],
+                   offset_ = roaches$offset[roaches$test == 0],
                    beta_prior_scale = 2.5,
                    alpha_prior_scale = 5.0
                    )
@@ -115,7 +115,7 @@ data_test <- list(y = roaches$y[roaches$test == 1],
                                          c("roach1", "treatment", "senior")]),
                    N = nrow(roaches[roaches$test == 1,]),
                    K = 3,
-                   offset = roaches$offset[roaches$test == 1],
+                   offset_ = roaches$offset[roaches$test == 1],
                    beta_prior_scale = 2.5,
                    alpha_prior_scale = 5.0
                    )
@@ -178,7 +178,7 @@ for(k in 1:10){
                                          c("roach1", "treatment", "senior")]),
                    N = nrow(roaches[roaches$fold != k,]),
                    K = 3,
-                   offset = roaches$offset[roaches$fold != k],
+                   offset_ = roaches$offset[roaches$fold != k],
                    beta_prior_scale = 2.5,
                    alpha_prior_scale = 5.0
                    )
@@ -187,7 +187,7 @@ for(k in 1:10){
                                          c("roach1", "treatment", "senior")]),
                    N = nrow(roaches[roaches$fold == k,]),
                    K = 3,
-                   offset = roaches$offset[roaches$fold == k],
+                   offset_ = roaches$offset[roaches$fold == k],
                    beta_prior_scale = 2.5,
                    alpha_prior_scale = 5.0
                    )