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 = 200, chains = 1)

SAMPLING FOR MODEL 'walker_lm' NOW (CHAIN 1).
Chain 1: 
Chain 1: Gradient evaluation took 0.001438 seconds
Chain 1: 1000 transitions using 10 leapfrog steps per transition would take 14.38 seconds.
Chain 1: Adjust your expectations accordingly!
Chain 1: 
Chain 1: 
Chain 1: WARNING: There aren't enough warmup iterations to fit the
Chain 1:          three stages of adaptation as currently configured.
Chain 1:          Reducing each adaptation stage to 15%/75%/10% of
Chain 1:          the given number of warmup iterations:
Chain 1:            init_buffer = 15
Chain 1:            adapt_window = 75
Chain 1:            term_buffer = 10
Chain 1: 
Chain 1: Iteration:   1 / 200 [  0%]  (Warmup)
Chain 1: Iteration:  20 / 200 [ 10%]  (Warmup)
Chain 1: Iteration:  40 / 200 [ 20%]  (Warmup)
Chain 1: Iteration:  60 / 200 [ 30%]  (Warmup)
Chain 1: Iteration:  80 / 200 [ 40%]  (Warmup)
Chain 1: Iteration: 100 / 200 [ 50%]  (Warmup)
Chain 1: Iteration: 101 / 200 [ 50%]  (Sampling)
Chain 1: Iteration: 120 / 200 [ 60%]  (Sampling)
Chain 1: Iteration: 140 / 200 [ 70%]  (Sampling)
Chain 1: Iteration: 160 / 200 [ 80%]  (Sampling)
Chain 1: Iteration: 180 / 200 [ 90%]  (Sampling)
Chain 1: Iteration: 200 / 200 [100%]  (Sampling)
Chain 1: 
Chain 1:  Elapsed Time: 1.4228 seconds (Warm-up)
Chain 1:                1.24124 seconds (Sampling)
Chain 1:                2.66404 seconds (Total)
Chain 1: 
>   
> 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 = 200, chains = 1)

SAMPLING FOR MODEL 'walker_lm' NOW (CHAIN 1).
Chain 1: 
Chain 1: Gradient evaluation took 0.001459 seconds
Chain 1: 1000 transitions using 10 leapfrog steps per transition would take 14.59 seconds.
Chain 1: Adjust your expectations accordingly!
Chain 1: 
Chain 1: 
Chain 1: WARNING: There aren't enough warmup iterations to fit the
Chain 1:          three stages of adaptation as currently configured.
Chain 1:          Reducing each adaptation stage to 15%/75%/10% of
Chain 1:          the given number of warmup iterations:
Chain 1:            init_buffer = 15
Chain 1:            adapt_window = 75
Chain 1:            term_buffer = 10
Chain 1: 
[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