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2013 Jan 13
1
R error: system is computationally singular when building GMM model
...I built the generalized method of moments model to estimate the sales rank
in the bookstore using plm package in R.
The equation is:
data1.gmm <- pgmm(dynformula(lnsales_rank ~ ln_price + avg_ham_rate +
avg_spam_rate + num_of_ham+ num_of_spam + ship_code2 +ship_code3
+ship_code4+ ship_code5+ ship_code6 + ship_ code7, lag = list(0, 0, 0,
0,0,0,0,0,0,0,0,0), log =FALSE), data=data, effect = "individual", model =
"twosteps", transformation = "ld",gmm.inst = ~ ln_price, lag.gmm =2)
However, error message: Error in solve.default(Reduce("+", A1)) :
system is...