On macOS Sonoma with brms 2.20.5, cmdstanr 0.6.1 and cmdstan 2.33.1 I’m getting 2–8ish warnings about proposal rejections that appear regardless of `silent`

or `refresh`

settings (i.e. even when using `silent = 2, refresh = 0`

.

These warnings didn’t appear with earlier versions of brms and/or cmdstanr—I’m not sure which version of which package introduced them (there’s an issue at {cmdstanr} from April).

The model fits fine; it just emits a ton of unhidable output now.

```
> brms::brm(mpg ~ cyl, data = mtcars, backend = "cmdstanr", silent = 2)
Compiling Stan program...
ld: warning: duplicate -rpath '/Users/andrew/.cmdstan/cmdstan-2.33.1/stan/lib/stan_math/lib/tbb' ignored
Start sampling
Chain 1 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 1 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 1 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 1 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 1
Chain 1 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 1 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 1 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 1 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 1
Chain 1 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 1 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 1 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 1 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 1
Chain 1 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 1 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 1 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 1 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 1
Chain 1 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 1 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 1 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 1 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 1
Chain 1 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 1 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 1 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 1 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 1
Chain 1 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 1 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 1 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 1 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 1
Chain 2 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 2 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 2 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 2 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 2
Chain 2 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 2 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 2 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 2 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 2
Chain 2 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 2 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 2 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 2 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 2
Chain 2 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 2 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 2 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 2 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 2
Chain 3 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 3 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 3 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 3 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 3
Chain 3 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 3 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 3 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 3 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 3
Chain 3 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 3 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 3 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 3 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 3
Chain 3 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 3 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 3 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 3 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 3
Chain 3 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 3 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 3 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 3 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 3
Chain 3 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 3 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 3 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 3 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 3
Chain 3 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 3 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 3 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 3 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 3
Chain 3 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 3 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 3 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 3 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 3
Chain 4 Informational Message: The current Metropolis proposal is about to be rejected because of the following issue:
Chain 4 Exception: normal_id_glm_lpdf: Scale vector is inf, but must be positive finite! (in '/var/folders/17/g3pw3lvj2h30gwm67tbtx98c0000gn/T/RtmpUngC6I/model-ca65460d50d3.stan', line 34, column 4 to column 62)
Chain 4 If this warning occurs sporadically, such as for highly constrained variable types like covariance matrices, then the sampler is fine,
Chain 4 but if this warning occurs often then your model may be either severely ill-conditioned or misspecified.
Chain 4
Family: gaussian
Links: mu = identity; sigma = identity
Formula: mpg ~ cyl
Data: mtcars (Number of observations: 32)
Draws: 4 chains, each with iter = 2000; warmup = 1000; thin = 1;
total post-warmup draws = 4000
Population-Level Effects:
Estimate Est.Error l-95% CI u-95% CI Rhat Bulk_ESS Tail_ESS
Intercept 37.89 2.18 33.56 42.15 1.00 3126 2713
cyl -2.88 0.34 -3.54 -2.19 1.00 3084 2590
Family Specific Parameters:
Estimate Est.Error l-95% CI u-95% CI Rhat Bulk_ESS Tail_ESS
sigma 3.33 0.45 2.59 4.33 1.00 3142 2445
Draws were sampled using sample(hmc). For each parameter, Bulk_ESS
and Tail_ESS are effective sample size measures, and Rhat is the potential
scale reduction factor on split chains (at convergence, Rhat = 1).
```