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------- End of Forwarded Message CC: visad-list@xxxxxxxxxxxxx John, > Why is there a field "ManifoldDimension" in a SimpleSet? > . . . > definition of manifold as "a subset of Rn, along with an invertable > and differentiable function phi:Rm -> Rn", then are you adding the > function phi to the class SimpleSet? There is a ManifoldDimension partly because there is no explicit phi. The manifold is not explicitly documented. But the ManifoldDimension provides information about the topology of the Set. That is, the set is generally defined by a finite set of points, either explict or implicit (e.g., FloatSet, LinearSet), and a connection topology between those points. A Set with DomainDimension = 3 and ManifoldDimension = 2 will have a topology consisting of squares or triangles, whereas a Set with DomainDimension = 3 and ManifoldDimension = 3 will have a topology consisting of cubes or tetrahedra. There are other consequences of ManifoldDimension. If ManifoldDimension != DomainDimension then (at least our current) Set classes refuse to interpolate since they cannot really be sure that the point being interpolated to lies on the manifold. To be sure, this whole business with ManifoldDimension is an area for future development, since nothing in the existing system prohibits Sets that do document phi. However, I believe that it is not the most pressing need right now. Actually, the most pressing need is probably UIs and other VisAD extension packages that hide the complexity of the Data model (which leads into my answer to Glenn's email). Regards, Bill - ---------------------------------------------------------- Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI 53706 whibbard@xxxxxxxxxxxxx 608-263-4427 fax: 608-263-6738 http://www.ssec.wisc.edu/~billh/vis.html - ---------------------------------------------------------- Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI 53706 whibbard@xxxxxxxxxxxxx 608-263-4427 fax: 608-263-6738 http://www.ssec.wisc.edu/~billh/vis.html ------- End of Forwarded Message
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