Opened 3 years ago

Last modified 4 months ago

#28750 new defect

another maxima integration bug

Reported by: Frédéric Chapoton Owned by:
Priority: major Milestone: sage-9.8
Component: calculus Keywords: integrate, maxima
Cc: Nasser, Karl-Dieter Crisman, Samuel Lelièvre, Dave Morris Merged in:
Authors: Reviewers:
Report Upstream: Reported upstream. No feedback yet. Work issues:
Branch: Commit:
Dependencies: Stopgaps:

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Description (last modified by Frédéric Chapoton)

var('s,x,y')
q = sqrt(2)
g = (x - y) * sin((x - y) / s)
g1 = integral(g({s:q}), y)
g2 = integral(g({s:q}), y, algorithm='sympy')
g3 = integral(g, y).subs({s:q})

Then g2 and g3 have the correct derivative, but not g1.

possibly related to #30378 and #31530

Change History (14)

comment:1 Changed 3 years ago by Erik Bray

Milestone: sage-9.0sage-9.1

Ticket retargeted after milestone closed

comment:2 Changed 3 years ago by Matthias Köppe

Milestone: sage-9.1sage-9.2

Moving tickets to milestone sage-9.2 based on a review of last modification date, branch status, and severity.

comment:3 Changed 2 years ago by Matthias Köppe

Milestone: sage-9.2sage-9.3

comment:4 Changed 21 months ago by Matthias Köppe

Milestone: sage-9.3sage-9.4

Moving to 9.4, as 9.3 has been released.

comment:5 Changed 20 months ago by Frédéric Chapoton

EDIT:

in sage 9.4.b0, numerically :

the derivative of g1 is wrong ; those of g2 and g3 are ok

Last edited 20 months ago by Frédéric Chapoton (previous) (diff)

comment:6 Changed 20 months ago by Frédéric Chapoton

Cc: Matthias Köppe Samuel Lelièvre Dave Morris added
Description: modified (diff)

comment:7 Changed 20 months ago by Frédéric Chapoton

directly in maxima:

maxima: a: sin((x-y)/sqrt(2))*(x-y);                                            
sin((x-y)/sqrt(2))*(x-y)

maxima: g: integrate(a,y);                                                      
((2^(3/2)+2)*sin(y/sqrt(2)-x/sqrt(2))+(((-2^(3/2))-2)*(y/sqrt(2)-x/sqrt(2))+((-sqrt(2))-2)*x)*cos(y/sqrt(2)-x/sqrt(2)))/2+sqrt(2)*x*cos(y/sqrt(2)-x/sqrt(2))

comment:8 Changed 20 months ago by Frédéric Chapoton

Cc: Nasser added

comment:9 Changed 20 months ago by Frédéric Chapoton

Cc: Karl-Dieter Crisman added; Matthias Köppe removed

This should be reported upstream to maxima. Karl-Dieter, would you please do that ?

For info, the correct answer as given by sympy is

sqrt(2)*(x - y)*cos(-1/2*sqrt(2)*(x - y)) + 2*sin(-1/2*sqrt(2)*(x - y))

comment:10 Changed 20 months ago by Karl-Dieter Crisman

Report Upstream: N/AReported upstream. No feedback yet.

comment:11 Changed 17 months ago by Matthias Köppe

Milestone: sage-9.4sage-9.5

comment:12 Changed 14 months ago by Matthias Köppe

Milestone: sage-9.5sage-9.6

comment:13 Changed 9 months ago by Matthias Köppe

Milestone: sage-9.6sage-9.7

comment:14 Changed 4 months ago by Matthias Köppe

Milestone: sage-9.7sage-9.8
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