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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hello,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m interested in using PETSc to manage distributed arrays. Based on my reading about the DMDA objects, I see that ghost points can be communicated in box-type stencils or star-type stencils.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>For my application, assume that I have a 2D DMDA object with star-type stencils. For a typical local calculation, I only need to access ghost values from two of the four directions at a time. For example, I’d like access to ghost values in the South and East directions, but not in the North or West directions. Communicating North and West data would seem to be wasting bandwidth. Is there any way to accomplish this?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal>Greg<o:p></o:p></p></div></body></html>