Market shares

[bjornerstedt]

Random products in SimMarket results in unreasonable market shares in
market.summary(). See /blp/dev/gmm/gmm_test.m, setting m.model.randomProducts = true;

[bjornerstedt]

With randomProducts, averages are calculated over all markets where the product is sold. When it is missing the share should be zero, not missing. Shares conditional on being in the market are higher than unconditional shares, leading to aggregate shares being > 1.