factor bug

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Hello --

Not sure anyone is tracking this, but the factor program at:
http://cpansearch.perl.org/src/CWEST/ppt-0.14/html/commands/factor/factor.feinberg
does indeed have a bug. Try:
factor 3599
and it will report this as prime, though 59*61 == 3599.
The bug is presumably in the line:
$max-- if $max %2;                   # Make the max odd
as this does NOT force $max to be odd, but rather even.
Not sure if the preferred rectification is:
$max++ unless $max %2;
-or-
$max-- unless $max %2;
though either works for the specific case of 3599.

Best wishes,
-- David S. Nunn, PhD
[email protected]

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<div dir=3D"ltr">Hello --<div><br></div><div>Not sure anyone is tracking th=
is, but the factor program at:</div><div><a href=3D"http://cpansearch.perl.=
org/src/CWEST/ppt-0.14/html/commands/factor/factor.feinberg">http://cpansea=
rch.perl.org/src/CWEST/ppt-0.14/html/commands/factor/factor.feinberg</a><br=
>
</div><div>does indeed have a bug. Try:</div><div>factor 3599</div><div>and=
 it will report this as prime, though 59*61 =3D=3D 3599.</div><div>The bug =
is presumably in the line:</div><div>$max-- if $max %2; =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 # Make the max odd<br>
</div><div>as this does NOT force $max to be odd, but rather even.</div><di=
v>Not sure if the preferred rectification is:</div><div>$max++ unless $max =
%2;</div><div>-or-</div><div>$max-- unless $max %2;</div><div>though either=
 works for the specific case of 3599.</div>
<div><br></div><div>Best wishes,<br><div dir=3D"ltr"><div>-- David S. Nunn,=
 PhD</div><div><a href=3D"mailto:[email protected]" target=3D"_blank">=
[email protected]</a>=C2=A0</div></div>
</div></div>

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