On Tue, 18 Dec 2018, Artur T. wrote:
 Ok, this is what I expected after having identified this
"behavior". 
 Nevertheless, I was surprised to see this happen. Of course one can't 
 interpolate the initial or last obs. However, I guess the user usually 
 expects that this corner-issue is somehow solved for him/her or at least a 
 warning is returned. 
Until we find a better solution, the current behaviour is now explained 
more clearly in the documentation.
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   Riccardo (Jack) Lucchetti
   Dipartimento di Scienze Economiche e Sociali (DiSES)
   Università Politecnica delle Marche
   (formerly known as Università di Ancona)
   r.lucchetti(a)univpm.it
   
http://www2.econ.univpm.it/servizi/hpp/lucchetti
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