How to print gradient in .stan for debug

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

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).

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


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.

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