6.6.3.2.1. statsmodels.sandbox.panel.panel_short.sum_outer_product_balanced

statsmodels.sandbox.panel.panel_short.sum_outer_product_balanced(x, n_groups)

sum outerproduct dot(x_i, x_i.T) over individuals

where x_i is (nobs_i, 1), and result is (nobs_i, nobs_i)

reshape-dot version, for x.ndim=1 only