Thanks for the help to my specific problem. More generally, what should have clued me in to a contract or type error when the only message received had to do with y plot bounds? Just looking for practical advice to help me figure out things on my own going forward.
On Tuesday, June 15, 2021 at 9:46:37 AM UTC-4 Ben Greenman wrote: > On 6/15/21, Britt Anderson <[email protected]> wrote: > > > > I was starting to explore plot and I am getting a behavior I do not > > understand. plot doesn't seem to be able to figure out the bounds for > > something that seems pretty straight-forward. When I give bounds as an > > optional argument I don't see the line I expect to see. Can anyone > provide > > me some pointers? I feel like I am just missing something conceptually > and > > would appreciate some guidance. Here is some minimal code to demonstrate > > the problem. I get a plot square, but no line, and I can demonstrate that > > the function generates reasonable numbers for this range of inputs. > > > > > > > > #lang racket > > (require plot) > > (require math/distributions) > > > > (define (norm-prior mu) > > (lambda (sd) > > (lambda (ind) > > (* ind (flnormal-pdf mu sd ind #f))))) > > > > (define d ((norm-prior 0.5) 0.1)) > > > > (plot (function d 0 1 #:y-min 0.0 #:y-max 2.0 #:samples 100)) > > > > (map d (range 0.0 1.0 0.01)) > > > > This is tricky. > > Plot is calling your function `d` with inputs like 0, 1/99, and 1. All > of those give contract errors --- try (d 0) for yourself. > > But when a plot function throws an error, the library ignores the > problem & keeps trying to draw a picture. > > To fix, I'd change `norm-prior` to make a flonum: > > (define (norm-prior mu) > (lambda (sd) > (lambda (ind) > (* ind (flnormal-pdf mu sd (exact->inexact ind) #f))))) > > [[ Maybe plot should check if a function renderer produces no output > and throw an error then. ]] > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/8021ed6d-f5f2-4279-9481-ad66eab9e762n%40googlegroups.com.
