I'm trying to use the SemiMarkov package and I want to change one small line of code in there. I've done some digging via:
getAnywhere("semiMarkov")
& I've identified that I want to change this line:
hessian <- diag(ginv(hessian(V, solution)))
to try something like:
hessian <- diag(ginv(pracma::hessian(V, solution)))
How do I go about this? Do I need to rebuild the package from scratch, and if so do I need rTools etc for this, or is there a simple-ish workaround (I'm a relevant R novice)? I've done some searching online and can't find anything obvious. Any ideas/pointers gratefully appreciated.
Answer
If you'd like to simply test out the effect of that change in an interactive R session, you can do so using trace(). Here's how:
- Type
trace("semiMarkov", edit=TRUE) - In the text editor that that launches, edit the line of interest.
- Save the modified file.
- Close the text editor
- Back in R, use the modified function.