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Re: FixedPoint[Cos, 1.0]

• To: mathgroup at smc.vnet.net
• Subject: [mg119398] Re: FixedPoint[Cos, 1.0]
• From: "Tony Harker" <a.harker at ucl.ac.uk>
• Date: Thu, 2 Jun 2011 07:14:29 -0400 (EDT)

I get
In[40]:= FixedPoint[Cos, 1.0]

Out[40]= 0.739085

In[41]:= $Version

Out[41]= "8.0 for Microsoft Windows (64-bit) (February 23, 2011)"
  
   Tony Harker

]-> -----Original Message-----
]-> From: J Siehler [mailto:jsiehler at gmail.com]
]-> Sent: 31 May 2011 12:49
]-> To: mathgroup at smc.vnet.net
]-> Subject: [mg119351] FixedPoint[Cos, 1.0]
]-> 
]-> My numerical analysis students this past term pointed out to me that the
]-> command
]-> 
]-> FixedPoint[Cos, 1.0]
]-> 
]-> which is the first example in the Information for FixedPoint doesn't
ever
]-> finish running (or, not in any reasonable amount of time).  We tried
this on
]-> serveral versions of Mathematica (6.x, 7.x, and 8.x), all on OS X, and
got the
]-> same nonresult.
]-> 
]-> It can be forced by specifying something like FixedPoint[Cos, 1.0,
SameTest
]-> -> (Abs[#1 - #2] < 10^-10 &)] or FixedPoint[Cos, 1.0, 40], but it seems
like
]-> that should be unnecessary, and the form given in the documentation
]-> should work.  Can anybody else confirm this behavior?  Am I missing
]-> something totally obvious here?