       How to ensure ( Overflow[] -> Indeterminate )

• To: mathgroup at smc.vnet.net
• Subject: [mg114705] How to ensure ( Overflow[] -> Indeterminate )
• From: "Ted Ersek" <ersekt at md.metrocast.net>
• Date: Mon, 13 Dec 2010 03:54:41 -0500 (EST)

```Recall the thread:  "Are these bugs fixed in Mathematica 8 ?"
found at http://forums.wolfram.com/mathgroup/archive/2010/Dec/msg00260.html

There we discussed cases where some (many?) functions in  Mathematica 8
treat any Overflow as a positive real number.   Fortunately one rarely gets an
overflow in Mathematica because \$MaxNumber is a very large value.
However, if you ever do get an Overflow you can't have faith in any
computation that
makes use of your Overflow[].

Until Mathematica can work with an overflow reliably we are better of using
the following.

In:= Off[General::ovfl];
Unprotect[Overflow];
Overflow[]=Indeterminate;

-------------------------------------
Well at first that seems to work for me using
\$Version  =  "7.0 for Microsoft Windows (32-bit) (January 30, 2009)."

In:=  0 <  3-Overflow[]

Out=  0 < Indeterminate

In:= Element[ 3-Overflow[],Reals ]

Out=  Element[ Indeterminate, Reals ]

Bu wait it only works in simple cases. Consider the next two examples.

In:= 0<3-4*\$MaxNumber

Out= True

In:= Element[(\$MaxNumber (-0.664-0.747 I))^4,Reals]

Out= True

----------------------------------
Does anyone know how we can ensure an Overflow[] is always converted to
Indeterminate?

-- Ted Ersek --

```

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