I have the following data:

mat <- c(88.96438,21.20548,53.06301,76.89863,112.99726,83.96712,119.80274,53.06301 ,112.99726,53.06301)
ytm <- c(0.09380442,0.07378878,0.08823629,0.09428388,0.10381418,0.09652231 ,0.10485382,0.08865775,0.10345890,0.09040975)

Where $mat$ are bond maturities (in months, as the function requires) and $ytm$ are the corresponding yields (in years).

I get however the following error when performing the estimation:

Nelson.Siegel(rate=ytm, maturity = mat)
Error in seq.default(maturity[1], maturity[pillars.number], by = 0.5) : 
  wrong sign in 'by' argument

Can anyone please tell me why?



1 Answer 1


If you want people to help you, you really should provide a reproducible example. In particular, you should mention where the Nelson.Siegel function comes from. But as a guess, the maturities (mat) very likely have to be sorted in increasing order.

  • $\begingroup$ Arranging in increasing order did the trick! Thanks! And I think I could not have been more explicit about where the function Nelson.Siegel comes from, please read the tittle. $\endgroup$
    – Nobody
    Feb 11, 2020 at 12:27
  • $\begingroup$ Yes, indeed. But for people (like me) who copy/paste code into R sessions, adding a call to require/librarywould have helped ;-) Anyway, I am glad it worked. $\endgroup$ Feb 11, 2020 at 14:06

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