Sure, the documentation below shows the function, but it doesn’t specify d1 and d2. The reference paper shows di=ai*bi, but I’m getting slightly different results when writing out that pdf and comparing it to the package. Where does duration fit into this?

Using the canonical HRF with default parameters, I wrote the following pdf:

((t/(a_1*b_1))^a_1) exp(-(t-a_1b_1)/b_1)-0.15*((t/(a_2

*b_2))^12)*(exp(-(t-a_2*b_2))/b_2)

Thank you in advance!