# Sums over Brillouin zone¶

class triqs.sumk.SumkDiscreteFromLattice(lattice, patch=None, n_points=8, method='Riemann')[source]
• Computes
$G \leftarrow \sum_k (\omega + \mu - \epsilon_k - \Sigma(k,\omega))^{-1}$

for GF functions with blocks of the size of the matrix eps_k with a discrete sum.

• The object contains the discretized hoppings and points in the arrays hopping, bz_points,bz_weights,mu_pattern,overlap (IF non orthogonal) It can also generate a grid (ReComputeGrid) for a regular grid or a Gauss-Legendre sum for the whole Brillouin Zone or a patch of the BZ.
GFBlocIndices

Returns the ONLY block indices accepted for the G and Sigma argument of the SumK function

Recompute_Grid(n_points, method='Riemann', Q=None)[source]

(Re)Computes the grid on the patch given at construction:

• n_points: Number of points in the BZ in EACH direction
• method: Riemann (default) or ‘Gauss’ (not checked)
• Q: anything from which a 1d-array can be computed.
computes t(k+Q) instead of t(k) (useful for bare chi_0)
n_kpts()

Returns the number of k points

resize_arrays(nk)

Just constructs the arrays, but without initializing them - nk: total number of k points