You're welcome. I forgot a step. Use Attribute to change "element type" from "quads" to "cubes"
Hans Fangohr <[EMAIL PROTECTED]>@opendx.watson.ibm.com on 05/10/2001 05:51:03 PM Please respond to [email protected] Sent by: [EMAIL PROTECTED] To: [email protected] cc: Subject: Re: [opendx-users] Howto to compute DivCurl from 2d data? Dear Lloyd, thank you very much for your answer. Your suggestion indeed makes the positions 3 dimensional. (It is great to read your answer: Even though the conversion from 2 to 3d-positions happens in many modules, it all makes sense. It's only hard to come up with this yourself in the beginning...) However, the cunning conversion doesn't change the connection type from quads to cubes (or whatever is appropriate in 3d). Thus, DivCurl complains "Operation not implemented: quads is an invalid connections type". Now, how can I convert those quad-connections into something 3dimensional that DivCurl accepts (cubes?)? Cheers, Hans On Wed, 9 May 2001, Lloyd A Treinish wrote: > > Yes, DivCurl expects 3d data on 3d positions. One workaround is too "fool" > DivCurl into thinking you have 3d positions is the following: > > | > Mark(,"positions") > | > Compute(,[a.x,.a.y,0]) > | > Unmark > | > DivCurl > | > Mark(,"positions") > | > Compute(,[a.x,.a.y]) > | > Unmark > | > Compute(,a.z) (to give you the z-component) > | > > As you can tell this is not ideal. An alternative would be to modify the > DivCurl code to handle 2d data. > > > > Hans Fangohr <[EMAIL PROTECTED]>@opendx.watson.ibm.com on 04/24/2001 > 02:50:41 PM > > Please respond to [email protected] > > Sent by: [EMAIL PROTECTED] > > > To: [email protected] > cc: > Subject: [opendx-users] Howto to compute DivCurl from 2d data? > > > > Dear all, > > I have a vector field with 3d data but the positions are 2d in the x-y > plane only (and the connections are quads). I.e. I have a 2d-plane of of > data, and at every data point there is a 3d vector. > > I want to compute the curl of the field (really I only want the > z-component), but connecting the data to DivCurl gives > "ERROR: DivCurl: Operation not implemented: quads is an invalid > connections type" > > I understand that it is hard for DivCurl to take the derivative of my data > with respect to z as I only have on value in this dimension. However, the > z-component of Curl should be computable since derivatives in x- and > y-direction can be obtained from my data. > > Can anyone suggest a method that allows me to use the DivCurl module on my > data? > > Or is it quicker to rewrite a special purpose DivCurl2d? (That would > involve taking derivates though, and I suspect DivCurl does this in a > clever way - so I would like to use it.) > > Thanks in advance, > > Hans > > > ---------------------------------------------- > Hans Fangohr > > High Performance Computing Group > Department of Electronics and Computer Science > Building 59, Level 3, Room 3237 > and > Quantum and Functional Matter Group > Department of Physics and Astronomy > > University of Southampton > Highfield > Southampton > SO17 1BJ > Great Britain > [EMAIL PROTECTED] > ---------------------------------------------- > > > > >
