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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


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

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