statsmodels.sandbox.regression.gmm.LinearIVGMM.calc_weightmatrix
LinearIVGMM.calc_weightmatrix(moms, weights_method='cov', wargs=(), params=None)
calculate omega or the weighting matrix Parameters:
moms : array, (nobs, nmoms) moment conditions for all observations evaluated at a parameter value weights_method : string ?cov? If method=?cov? is cov then the matrix is calculated as simple covariance of the moment conditions. see fit method for available aoptions for the weight and covarianc