Opened 8 years ago

Last modified 5 years ago

#11655 new defect

Maxima missing rectform simplification after integral()

Reported by: jan Owned by: burcin
Priority: major Milestone: sage-6.4
Component: symbolics Keywords:
Cc: kcrisman Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description

var('a b c x', domain='real')
A = (sin(a) * x^2+sin(b) *x + sin(c)) * exp(-x^2)
Aint = A.integrate(x,-infinity,infinity)

A.imag() is 0

Aint.imag() is a long expression, which doesn't simplify to 0. This surprising for the user.

A slightly different example, actually a generalization of the one above, just works:

var('a b c x', domain='real')
B = (a * x^2+b *x + c) * exp(-x^2)
Bint = B.integrate(x,-infinity,infinity)

Examples can be found here: http://demo.sagenb.org/home/pub/179

Change History (6)

comment:1 Changed 8 years ago by kcrisman

  • Cc kcrisman added

comment:2 Changed 6 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:3 Changed 6 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:4 Changed 6 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:5 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:6 Changed 5 years ago by rws

  • Summary changed from A.integrate() has imaginary part for real A to Maxima missing rectform simplification after integral()

This seems to be a missing rectform simplification because

sage: Aint.expand().simplify_rectform()
1/2*sqrt(pi)*sin(a) + sqrt(pi)*sin(c)

The bug is then rather that Maxima does it not in all cases.

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