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...d host to establish a connection? Thanks in advance ------------------------------------------------------------------- Jorge de la Vega Gongora | Telefono: (525) 5268 8379 Investigador | Fax: (525) 5268 8481 Banco de Mexico | email: jvega at banxico.org.mx Planeaci?n y Programaci?n de Emisi?n | web: http://www.stat.umn.edu/~jvega Calzada Legaria 691 M?dulo IV | Col. Irrigaci?n 11500 |

Why the warning messages (2:4)? > x <- rexp(1000,0.2) > fitdistr(x,"exponential",list(rate=1)) rate 0.219824219 (0.006951308) Warning messages: 1: one-diml optimization by Nelder-Mead is unreliable: use optimize in: optim(start, mylogfn, x = x, hessian = TRUE, ...) 2: NaNs produced in: dexp(x, 1/rate, log) 3: NaNs produced in: dexp(x, 1/rate, log) 4: NaNs

I am not sure if something is wrong with my programming or is a bug of chron or something else. In the following script, db is a large dataframe (dim(db)=c(60698,14)), then I select a very small part for a specific date and compute some basic statistics. date.base is a chron object foo<-function(db,date.base){ date.base<-as.numeric(date.base) #convert to number