Re: PBG of gyroid structure

On May 4, 2009, at 6:27 PM, Vinodkumar Saranathan wrote:

> Dear Steven and Mischa,
> Thanks for your suggestions, I was able to set up the dielectric  
> function.
>
> However, I was trying to reproduce the result of Maldovan et al. 2002:
> http://prola.aps.org/abstract/PRB/v65/i16/e165123
> where they calculate the PBG for a single gyroid (I4-1-32) structure  
> with a dielectric contrast of 13 and
> dielectric packing fraction 50%

Remember that the coordinates are passed to eps-func in the basis of  
the lattice basis, which is *not* Cartesian coordinates since you have  
a non-cubic lattice with non-orthogonal lattice vectors.

If you want to have a function of (x,y,z) Cartesian coordinates, you  
can convert the argument of eps-func with the lattice->cartesian  
function, e.g.

	(define (eps-func p-lattice)
		(let* ((p (lattice->cartesian))
			  (x (vector3-x p))
			  (y (vector3-y p))
			  (z (vector3-z p)))
			..... compute your function of (x,y,z)....
			))