Re: Geometry bug?

On Mon, 16 Oct 2006, Rob Engelen wrote:
> Take a look at the attached image, or run the script and look at the 
> geometry. The outer most cilinder is somehow truncated, and if I try to place 
> an object even further away from the center, it doesn't appear at all. Is 
> this a bug, or is it me?

It looks like you are getting confused regarding the coordinate system; 
your structure isn't periodic with respect to the lattice vectors you 
gave, and hence it looks funny when you convert to a rectangular cell 
(with mpb-data -r) and output.

For this kind of structure, you should use orthogonal lattice vectors. 
That is, your periodic unit cell should be a sqrt(3) x 1 supercell, with 
the unit length oriented along the waveguide.  That is, *without* a 
defect, your computational cell would look something like:

    o   o   o   o   o   o   o   o
      o   o   o   o   o   o   o
    o   o   o   o   o   o   o   o

Note also that you can use geometric-objects-duplicates to duplicate 
functions for arbitrary multiples of a given vector, rather than writing 
out all of the duplicates manually.

Steven