Running examples in ‘walker-Ex.R’ failed
The error most likely occurred in:

> ### Name: walker
> ### Title: Bayesian regression with random walk coefficients
> ### Aliases: walker
> 
> ### ** Examples
> 
> 
> ## note very low number of iterations for the CRAN checks
> 
> rw1_fit <- walker(Nile ~ -1 + 
+   rw1(~ 1, 
+     beta_prior = c(1000, 100), 
+     sigma_prior = c(0, 100)), 
+   sigma_y_prior = c(0, 100), 
+   iter = 50, chains = 1)

SAMPLING FOR MODEL 'walker_lm' NOW (CHAIN 1).

Gradient evaluation took 0.00142 seconds
1000 transitions using 10 leapfrog steps per transition would take 14.2 seconds.
Adjust your expectations accordingly!


WARNING: There aren't enough warmup iterations to fit the
         three stages of adaptation as currently configured.
         Reducing each adaptation stage to 15%/75%/10% of
         the given number of warmup iterations:
           init_buffer = 3
           adapt_window = 20
           term_buffer = 2

Iteration:  1 / 50 [  2%]  (Warmup)
Iteration:  5 / 50 [ 10%]  (Warmup)
Iteration: 10 / 50 [ 20%]  (Warmup)
Iteration: 15 / 50 [ 30%]  (Warmup)
Iteration: 20 / 50 [ 40%]  (Warmup)
Iteration: 25 / 50 [ 50%]  (Warmup)
Iteration: 26 / 50 [ 52%]  (Sampling)
Iteration: 30 / 50 [ 60%]  (Sampling)
Iteration: 35 / 50 [ 70%]  (Sampling)
Iteration: 40 / 50 [ 80%]  (Sampling)
Iteration: 45 / 50 [ 90%]  (Sampling)
Iteration: 50 / 50 [100%]  (Sampling)

 Elapsed Time: 0.325088 seconds (Warm-up)
               0.319306 seconds (Sampling)
               0.644394 seconds (Total)

>   
> rw2_fit <- walker(Nile ~ -1 + 
+   rw2(~ 1,
+     beta_prior = c(1000, 100), 
+     sigma_prior = c(0, 100), 
+     slope_prior = c(0, 100)), 
+   sigma_y_prior = c(0, 100), 
+   iter = 50, chains = 1)

SAMPLING FOR MODEL 'walker_lm' NOW (CHAIN 1).

Gradient evaluation took 0.001538 seconds
1000 transitions using 10 leapfrog steps per transition would take 15.38 seconds.
Adjust your expectations accordingly!


WARNING: There aren't enough warmup iterations to fit the
         three stages of adaptation as currently configured.
         Reducing each adaptation stage to 15%/75%/10% of
         the given number of warmup iterations:
           init_buffer = 3
           adapt_window = 20
           term_buffer = 2

[1] "Error in sampler$call_sampler(args_list[[i]]) : "
[2] "  c++ exception (unknown reason)"                
error occurred during calling the sampler; sampling not done
>   
> g_y <- geom_point(data = data.frame(y = Nile, x = time(Nile)), 
+   aes(x, y, alpha = 0.5), inherit.aes = FALSE) 
> g_rw1 <- plot_coefs(rw1_fit) + g_y
> g_rw2 <- plot_coefs(rw2_fit) + g_y
Stan model 'walker_lm' does not contain samples.
Error in 1:nrow(coef_data) : argument of length 0
Calls: plot_coefs
Execution halted