How to print gradient in .stan for debug

Interfaces RStan
1

I know print(“lp=”, target()) can print out log-posterior for debug.
How can I print gradient?
Thank you.
Ziyi Chen

2

You can’t. You can specify the diagnostic_file argument and the gradient vector (in the unconstrained space) will get written to that file for each iteration (not each leapfrog step).

3

I used diagnostic_file=“xxx.csv” in “sampling” function, and then

DiagFile.GMM=read.csv(“GMM_stan_unconstrained_noZ.csv”)

DiagFile.GMM is a 323*1 data.frame with the first few rows being strings, and the remaining rows being numbers, which is not readable.

Thank you.

4

I think you need to specify comment.char = "#" when you call read.csv

5

Thanks.