How to avoid under/overflow?
- To: mathgroup at smc.vnet.net
- Subject: [mg37925] How to avoid under/overflow?
- From: Kilian Weniger <weniger at tm.uka.de>
- Date: Tue, 19 Nov 2002 20:58:41 -0500 (EST)
- Organization: University of Karlsruhe, Germany
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
is Mathematica able to compute the following equation with products of
veryvery-close-to-one values?
f[R_, N_] := 1 - Exp[-N]*(1 - N/R)^(N - R - 1/2)
f[2^63, 10000]
After typing the equation, I always get under/overlows:
General::"ovfl": "Overflow occurred in computation."
General::"unfl": "Underflow occurred in computation."
General::"unfl": "Underflow occurred in computation."
General::"unfl": "Underflow occurred in computation."
General::"stop": "Further output of \!\(General :: \"unfl\"\) will be \
suppressed during this calculation."
I also tried to increase the allowed exponent range with
SetArithmetic[99, 10, ExponentRange -> {-999, 999}, MixedMode -> True,
IdealDivide -> True, RoundingRule -> RoundToEven]
or to increase the precision with
N[f[2^63, 10000], 100000]
but it didn't help. Any suggestions?
thanks,
Kilian