MathGroup Archive 1995

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Bug in SeriesData

  • To: mathgroup at christensen.cybernetics.net
  • Subject: [mg1255] Bug in SeriesData
  • From: steve at tweedledee.ucsb.edu (Steve Trainoff)
  • Date: Fri, 26 May 1995 08:01:03 -0400
  • Organization: University of California, Santa Barbara

I was running a long MMA program which generated the following expression  
somewhere in the middle.  

 2
x  + O[x]

This should be impossible to generate.  A little detective work with FullForm revealed the problem illustrated below.  It appears that SeriesData doesn't check to see if the series coefficients are functions of the series parameter.

Mathematica 2.0 for NeXT
Copyright 1988-91 Wolfram Research, Inc.

In[1]:= SeriesData[x, 0, {x^2}, 0, 1, 1]

         2
Out[1]= x  + O[x]		(* The infamous expression *)

In[2]:= SeriesData[x, 0, {1,x}, 0, 2, 1]

                      2
Out[2]= 1 + x x + O[x]		(* My personal favorite *)


--

..STeve
------------------------------------
Insert pithy maxim here...
steve at tweedledee.ucsb.edu (NeXT mail)
91 Wolfram Research, Inc.

In[1]:= SeriesData[x, here...
steve at tweedledee.ucsb.edu (NeXT mail)


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