Vladimir Eremeev wrote: > > Dear R experts, > > I have a Matlab code which I am translating to R in order to examine and > enhance it. > First of all, I need to reproduce in R the results which were already > obtained in Matlab (to make sure that everything is correct). > > There are some matrix manipulations and '\' operation among them in the > code. > > I have the following data frame > >> ABS.df > Pro syn unk Chl > Y Nh V1 > [skip] > >> qr.solve(ABS.df[,1:6],ABS.df[,7]) > Pro syn unk Chl Y Nh > 0.3877544 0.4282277 0.2221960 -0.8668715 0.2821082 -1.3696411 > > This reproduces the Matlab's numbers > However, I used to lm, its syntax seems to me more clear. > > ?lm says that it uses QR decomposition to fit the model. > Trying it: > >> coef(lm(V1~Pro+syn+unk+Chl+Y+Nh,data=ABS.df)) > (Intercept) Pro syn unk Chl > Y Nh > 0.001640184 0.417253116 0.351472810 0.196977369 -0.899729874 > 0.265585292 -1.181526491 > > Numbers differ. > Obviously, I don't understand something. > Please, could you clarify, what? > Thank you. > > This was because of implied intercept term. > lm(V1~Pro+syn+unk+Chl+Y+Nh+0,data=ABS.df) Call: lm(formula = V1 ~ Pro + syn + unk + Chl + Y + Nh + 0, data = ABS.df) Coefficients: Pro syn unk Chl Y Nh 0.3878 0.4282 0.2222 -0.8669 0.2821 -1.3696 That is, reproduces earlier results. -- View this message in context: http://www.nabble.com/qr.solve-and-lm-tf3757650.html#a10620691 Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.