id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
27304 Bug in factorization of simple symbolic expressions egourgoulhon "As reported in this [https://ask.sagemath.org/question/45469 ask.sagemath question], we have currently (Sage 8.7.beta3):
{{{
sage: factor(2*exp(x) + exp(-x))
3*e^x
}}}
as well as
{{{
sage: factor(x*exp(-x) + exp(-x))
(x + 1)*e^x
}}}
Another example of erroneous result exhibited in https://groups.google.com/d/msg/sage-devel/ytLqIb4soLw/c14ZKGqcAAAJ is
{{{
sage: var('t u')
(t, u)
sage: L = (u + t)/(u - t)
sage: factor(L.substitute(t=sqrt(u)))
(u + 1)/(u - 1)
}}}
This bug is there since at least Sage 8.4.beta4. It is not in Sage 8.3, hence it must have been introduced between 8.4.beta0 and 8.4.beta4. It seems to have been introduced in #23835 (see comment:5).
" defect closed blocker sage-8.8 symbolics fixed factor, exponential, pynac rws bpage Benjamin Hackl Emmanuel Charpentier N/A 7c2432ce2fdfe7eb905b91179a0fcaccef3d0a52 7c2432ce2fdfe7eb905b91179a0fcaccef3d0a52