On Aug 25, 2008, at 4:30 PM, Zhu, Lei wrote: > (in-volume (volume (center 0 1 0) (size 2 0 0)) output-efield-z)) > .............. > > I got 22 Ez.along x-axis from -1 to 1. > Why the number of Ez is not 23, but 22? > Why is not Ez at points (-1,0), (-0.9,0), (-0.8,0),(-0.7,0), > (-0.6,0), (-0.5,0),(-0.4,0), (-0.3,0), (-0.2,0),(-0.1,0), > (0,0), ........(1,0) plus two extra pixels on each boundary?
Because (-1,0) is not one of the grid points that it outputs. If I remember correctly, I think the centermost grid points are -1.05,0 and -0.95,0 ... basically, the hdf5 output interpolates everything it outputs to the center of each grid voxel, hence it is shifted by 0.5/ resolution from what you are expecting. Hence 22 pixels in this case, because there is no output at the grid point which is exactly in the center. Steven _______________________________________________ meep-discuss mailing list [email protected] http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
