def __init__(self, grid, beta=0.1, nmaxold=7, weight=50.0):
self.beta = beta
self.nmaxold = nmaxold
self.weight = weight
self.x_iG = [] #densities
self.R_iG = [] #Residuals
self.A_ii = np.zeros((0,0))
self.dNt = 1.0 # initial error
if self.weight == 0.0:
self.use_metric = False
else:
self.use_metric = True
self.metric = Metric(grid, self.weight)
