topic Re: Convex hull algorithm in SAS/STAT or SAS/BASE in Graphics Programming

Convex hull algorithm in SAS/STAT or SAS/BASE

brophymj — Fri, 21 Aug 2015 09:02:01 GMT

I don't have SAS/IML license so I was wondering if there is an algorithm that can be used in SAS/STAT or Base? I don't mind if it's not that efficient or is a bit messy. I want to calculate the convex hull of lots of 8 point polygons simulated as follows:

data obs;

do i= 1 to 8;

x= round(1000* ranuni(123),1);

y= round(1000* ranuni(789),1);

output;

end;

run;

Re: Convex hull algorithm in SAS/STAT or SAS/BASE

RW9 — Fri, 21 Aug 2015 09:28:19 GMT

Here is a link some algorithms, and there is liknk to Qhull there which may also help.

mg.metric geometry - Algorithm for finding the volume of a convex polytope - MathOverflow

Re: Convex hull algorithm in SAS/STAT or SAS/BASE

brophymj — Fri, 21 Aug 2015 10:08:05 GMT

Hi RW9

I'm interested in getting the convex hull of a two dimensional polygon - the volume of a polytope is not what I'm looking for.

If you download the student university edition of SAS do you get SAS/IML? I know you can do it fairly easily there.

Thanks

Re: Convex hull algorithm in SAS/STAT or SAS/BASE

RW9 — Fri, 21 Aug 2015 10:18:29 GMT

https://www.sas.com/content/dam/SAS/en_us/doc/factsheet/sas-university-edition-107140.pdf

Page 2, yes apparently you do get IML with that package.

Re: Convex hull algorithm in SAS/STAT or SAS/BASE

brophymj — Fri, 21 Aug 2015 10:37:43 GMT

Do you know if you can use the CVEXHULL Function in the university edition? there in an * next it so I'm not sure if this is included.

Re: Convex hull algorithm in SAS/STAT or SAS/BASE

RW9 — Fri, 21 Aug 2015 10:52:56 GMT

Afraid I have not used UE. Perhaps consider posting request for information in the SAS UE domain, or the IML domain as this isn't really graph related.