Perl: the Markov chain saw PerlMonks

### Re^3: log() and int() problem

by LanX (Chancellor)
 on Dec 25, 2012 at 21:11 UTC ( #1010288=note: print w/replies, xml ) Need Help??

in reply to Re^2: log() and int() problem
in thread log() and int() problem

> I solved my issue

you're very optimistic.

I delved into Devel::Peek and I'm still not sure which type casting or crossed thresholds produced different results for 2 and 3.

Anyway you're voyaging dangerous grounds, don't be surprised if your Float to Int conversions breaks again.

Better rely on on already shown pure integer arithmetic for your integer (sic) tests. (rule of thumb!)

Cheers Rolf

PS:

```lanx@nc10-ubuntu:~\$ perl -MDevel::Peek -e'\$|=1;\$e=2;\$x=log(5**\$e)/log(
+5); Dump \$x; print ("\n", (\$x==\$e) ? "" : "not " ,"equal\n\n");  Dump
+ \$x;'

SV = NV(0x9c86840) at 0x9c70f68
REFCNT = 1
FLAGS = (NOK,pNOK)
NV = 2

equal

SV = PVNV(0x9c50a60) at 0x9c70f68
REFCNT = 1
FLAGS = (IOK,NOK,pIOK,pNOK)
IV = 2
NV = 2
PV = 0

lanx@nc10-ubuntu:~\$ perl -MDevel::Peek -e'\$|=1;\$e=3;\$x=log(5**\$e)/log(
+5); Dump \$x; print ("\n", (\$x==\$e) ? "" : "not " ,"equal\n\n");  Dump
+ \$x;'

SV = NV(0x8fde840) at 0x8fc8f68
REFCNT = 1
FLAGS = (NOK,pNOK)
NV = 3

not equal

SV = PVNV(0x8fa8a60) at 0x8fc8f68
REFCNT = 1
FLAGS = (NOK,pIOK,pNOK)
IV = 3
NV = 3
PV = 0

UPDATE: improved code

Create A New User
Node Status?
node history
Node Type: note [id://1010288]
help
Chatterbox?
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others cooling their heels in the Monastery: (3)
As of 2017-08-19 17:15 GMT
Sections?
Information?
Find Nodes?
Leftovers?
Voting Booth?
Who is your favorite scientist and why?

Results (312 votes). Check out past polls.

Notices?