Working on adding curvature.

[fryguybob]

There are a couple of open questions with this still. One is how should we generalize the space that we compute at least the squared version. The second is what return values should we use. Would it be better to extend some scalar space with infinity explicitly?

Finally it would be nice to have this work for higher dimensions.

Also due to some failing systems here, I have not compiled this locally yet :D.

[byorgey]

Shouldn't this be Diagrams.TwoD.Curvature?

[fryguybob]

Hehe, yes. This was a consequence of not actually compiling...

[byorgey]

For representing a scalar space extended with positive infinity we already have Data.Monoid.PosInf from the monoid-extras package:

http://hackage.haskell.org/packages/archive/monoid-extras/0.2.2.2/doc/html/Data-Monoid-PosInf.html

Hmm, though it looks like it doesn't have a Num instance, which would probably be useful here, but that would be easy to add. Anyway, I am not saying this is definitely the way to go but it's worth thinking about. I don't know if there are other benefits to the (Double,Double) representation?

[fryguybob]

I think most uses will want to pattern match right away, so I'm not sure a Num instance is important. Having (Double,Double) does not signal this intent very well and could easy be mistaken for something else. I think I will change over to PosInf and add a radiusOfCurvature version.

[byorgey]

Is this ready to be merged? Or is there more work to do yet?

[fryguybob]

Yeah it should be fine to merge now. If we find a good place to put the
derivatives that can of course be factored out.

On Fri, Mar 29, 2013 at 4:54 PM, Brent Yorgey notifications@github.comwrote:

Is this ready to be merged? Or is there more work to do yet?

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/74#issuecomment-15660234
.