[LC++]Can I rely on log(0) = -inf ?
Dr Mark H Phillips
mark at austrics.com.au
Wed Oct 2 15:41:01 UTC 2002
Hi,
If I do
cout<<" log(0) = "<<log(0)<<endl;
cout<<" int(log(0)) = "<<int(log(0))<<endl;
I get
log(0) = -inf
int(log(0)) = -2147483648
Is "-inf" an "official double number"? Is this true across
architectures, or only for Intel?
Is the int cast of -inf guaranteed to give the minimum integer
or is this only gcc behaviour?
What I want to do is use the test
if (log(x)>0)
...;
and have it do the sensible thing in the case of x=0, but can
I rely on this, or should I do the more complicated:
if (x>0 && log(x)>0)
...;
Thanks,
Mark.
--
Dr Mark H Phillips
Research Analyst (Mathematician)
AUSTRICS - smarter scheduling solutions - www.austrics.com
Level 2, 50 Pirie Street, Adelaide SA 5000, Australia
Phone +61 8 8226 9850
Fax +61 8 8231 4821
Email mark at austrics.com.au
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