Optic. Weight of k points
Posted: Wed Mar 21, 2012 12:42 pm
Hi,
In the linear optic calculation, the code calls the routine getwtk, which calculates the weight of each k point by dividing the number of points on each star by the total number of points in all stars. These weight are needed in accumulating the susceptibility (chi).
My question is: I wonder why these weights are used! I understand that in some calculations involving summing over the k points, instead of running the sum over all the k points, one can use the virtue of symmetries to run the sum over only the irreducible brillouin zone and multiply each term in the sum by a corresponding (weight). However, in the linopt routine, the sum runs over all the brillouin zone, so why are these weight needed?
In the linear optic calculation, the code calls the routine getwtk, which calculates the weight of each k point by dividing the number of points on each star by the total number of points in all stars. These weight are needed in accumulating the susceptibility (chi).
My question is: I wonder why these weights are used! I understand that in some calculations involving summing over the k points, instead of running the sum over all the k points, one can use the virtue of symmetries to run the sum over only the irreducible brillouin zone and multiply each term in the sum by a corresponding (weight). However, in the linopt routine, the sum runs over all the brillouin zone, so why are these weight needed?