Displaying 2 results from an estimated 2 matches for "tetrahedron".
2007 Jul 10
2
integration over a simplex
...egrate over a multidimensional simplex. Has anyone
implemented such a thing in R?
I can transform an n-simplex to a hyperrectangle
but the Jacobian is a rapidly-varying (and very lopsided)
function and this is making adapt() slow.
[
A \dfn{simplex} is an n-dimensional analogue of a triangle or
tetrahedron.
It is the convex hull of (n+1) points in an n-dimensional Euclidean
space.
My application is a variant of the Dirichlet distribution:
With p~D(a), if length(p) = n+1 then the requirement that
all(p>0) and sum(p)=1 mean that the support of the
Dirichlet distribution is an n-simplex.
]
--
Ro...
2002 Oct 25
4
points on a sphere
Not an R question directly, but has anyone got a method for placing a
moderately large number of (near) equi-spaced points on a sphere? I have a
nasty feeling platonic solids are needed for exact solutions and I'm
thinking of samplings involving around 200 - 1000 regularly-spaced points,
Thanks,
Richard Rowe
Richard Rowe
Senior Lecturer
Department of Zoology and Tropical Ecology, James