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2007 Oct 16
1
underdetermined system
Hi, sorry, I'm an idiot.. and I know I'm missing something stupid.. I thought if we solve an underdetermine system with QR, my soln is: min ||x|| (L2 sense) such that Ax = b then say i have: > w <- matrix(c(1, 5), ncol=2) > sw = 2 > qrW = qr(t(w) %*% w) > qr.coef(qrW, t(w) %*% sw) [,1] [1,] 2 [2,] NA but we also have soln (0, 2/5) which obviously has a smaller distance in L2 than (2, 0). Am I missing something very obvious? Thanks a lot!!!! - yoooooooooooooooooo -- View this message in context: http://www.nabble...