Hi,

Recently I am testing my Stan file by running some fake data simulation, and sometimes I got the following error:

```
error_test3 <- stan(file = "testing_3.stan", data = data_test3,refresh=0, cores=5,iter = 500,chains=6)
```

here are whatever error messages were returned

```
[[1]]
Stan model 'testing_3' does not contain samples.
[[2]]
Stan model 'testing_3' does not contain samples.
[[3]]
Stan model 'testing_3' does not contain samples.
Warning messages:
1: In system(paste(CXX, ARGS), ignore.stdout = TRUE, ignore.stderr = TRUE) :
'-E' not found
2: In .local(object, ...) :
some chains had errors; consider specifying chains = 1 to debug
3: There were 748 divergent transitions after warmup. See
http://mc-stan.org/misc/warnings.html#divergent-transitions-after-warmup
to find out why this is a problem and how to eliminate them.
4: Examine the pairs() plot to diagnose sampling problems
5: The largest R-hat is 2.89, indicating chains have not mixed.
Running the chains for more iterations may help. See
http://mc-stan.org/misc/warnings.html#r-hat
6: Bulk Effective Samples Size (ESS) is too low, indicating posterior means and medians may be unreliable.
Running the chains for more iterations may help. See
http://mc-stan.org/misc/warnings.html#bulk-ess
7: Tail Effective Samples Size (ESS) is too low, indicating posterior variances and tail quantiles may be unreliable.
Running the chains for more iterations may help. See
http://mc-stan.org/misc/warnings.html#tail-ess
```

From my undertstanding of the above error messgae, the Stan file itself it ‘correct’ since 3 out f 6 chains actually got some returned values. But I am still confused why three of the chains did not contain any values, or is it becuase my Stan file itself it wrong?

Thx!