[sage-support] Re: Integration bug?

2018-10-02 Thread Simon King
On 2018-10-02, kcrisman wrote: > Please do. It's likely something related to > https://trac.sagemath.org/ticket/21440 and > https://trac.sagemath.org/wiki/symbolics#Integrationtickets where you can > browse to your heart's content :-) For some reason the wrong branch seems > to get chosen by

[sage-support] Re: Integration bug?

2018-10-02 Thread kcrisman
On Monday, October 1, 2018 at 4:55:14 PM UTC-4, Simon King wrote: > > Hi! > > I get the following with sage-8.4.beta5: > sage: f(x) = cos(pi*x) > sage: (f(x)*exp(-I*pi*x)).integral(x)(x=1/2) - > (f(x)*exp(-I*pi*x)).integral(x)(x=-1/2) > 1/2 > sage:

[sage-support] Re: Integration bug?

2017-10-27 Thread kcrisman
> integral(sqrt(1+cos(x)^2),x,0,pi) > > > > 0 > > The bug appears to be tickled by the Maxima package abs_integrate. > Without abs_integrate, integrate(sqrt(1 + cos(x)^2), x, 0, %pi) just > returns a noun expression. > > > Zero is decidedly not correct. The problem is apparently here:

[sage-support] Re: Integration bug?

2017-10-26 Thread Robert Dodier
On 2017-10-26, david.guichard wrote: > integral(sqrt(1+cos(x)^2),x,0,pi) > > 0 The bug appears to be tickled by the Maxima package abs_integrate. Without abs_integrate, integrate(sqrt(1 + cos(x)^2), x, 0, %pi) just returns a noun expression. > Zero is decidedly

[sage-support] Re: Integration of formal functions

2013-07-28 Thread Emmanuel Charpentier
Comments and (horrible !) workaround in Trac#14976http://trac.sagemath.org/ticket/14976 . HTH, Emmanuel Charpentier [ Snip ... ] -- You received this message because you are subscribed to the Google Groups

[sage-support] Re: Integration of formal functions

2013-07-27 Thread Emmanuel Charpentier
The problem seems to lie on Sage's side. In the native version of sage : Maxima 5.30.0 http://maxima.sourceforge.net using Lisp GNU Common Lisp (GCL) GCL 2.6.7 (a.k.a. GCL) Distributed under the GNU Public License. See the file COPYING. Dedicated to the memory of William Schelter. The function

[sage-support] Re: Integration of formal functions

2013-07-27 Thread Emmanuel Charpentier
By the way, the problem *might* be larger than that. In Maxima, one can do : (%i1) display2d:false; (%o1) false (%i2) define(h(x),integrate(f(t),t,g1(x),g2(x))); defint: lower limit of integration must be real; found g1(x) -- an error. To debug this try: debugmode(true); (%i3)

[sage-support] Re: Integration of formal functions

2013-07-27 Thread Robert Dodier
On 2013-07-27, Emmanuel Charpentier emanuel.charpent...@gmail.com wrote: (%i2) define(h(x),integrate(f(t),t,g1(x),g2(x))); defint: lower limit of integration must be real; found g1(x) -- an error. To debug this try: debugmode(true); Well, a way to make this work is to write define(h(x),

[sage-support] Re: Integration issue

2012-05-17 Thread kcrisman
On Thursday, May 17, 2012 1:52:38 AM UTC-4, ketchers wrote: I don't know how to get sage to understand domain : complex so I tried with assume and here is what happened. Does it make sense? Yes, it does. Our assumptions go through Maxima, and apparently assuming a variable is

[sage-support] Re: Integration issue

2012-05-16 Thread ketchers
https://lh6.googleusercontent.com/-BDfI2b3v4HA/T7SRx5zaqBI/AGo/Q6NEGFw8xQw/s1600/Screenshot+from+2012-05-17+00%3A50%3A25.png I don't know how to get sage to understand domain : complex so I tried with assume and here is what happened. Does it make sense? On Sunday, May 13, 2012

[sage-support] Re: Integration issue

2012-05-15 Thread Robert Dodier
On 2012-05-14, JamesHDavenport j.h.davenp...@bath.ac.uk wrote: It may be branch cut strangeness, but if so it is very strange. The integrand is clearly well-behaved, and the integral, while in terms of the incomplete gamma function, seems to be off the usual branch cut (negative real axis).

[sage-support] Re: Integration issue

2012-05-15 Thread kcrisman
It may be branch cut strangeness, but if so it is very strange. The integrand is clearly well-behaved, and the integral, while in terms of the incomplete gamma function, seems to be off the usual branch cut (negative real axis). Try domain:complex before calling integrate; that

[sage-support] Re: Integration issue

2012-05-15 Thread kcrisman
On Tuesday, May 15, 2012 2:36:34 AM UTC-4, Keshav Kini wrote: John H Palmieri jhpalmier...@gmail.com writes: This works for me: sage: numerical_integral(x*cos(x^3), 0, 0.5) (0.1247560409610376, 1.3850702913602309e-15) Interesting... sage:

[sage-support] Re: Integration issue

2012-05-15 Thread Robert Dodier
On 2012-05-15, kcrisman kcris...@gmail.com wrote: (%i3) domain:complex; (%o3) complex (%i4) integrate(x*cos(x^3),x,0,1/2); (%o4) gamma_incomplete(2/3,%i/8)/6+gamma_incomplete(2/3,-%i/8)/6-gamma(2/3)/3 Hmm. I get a different result. I am using the current Git version. domain : complex;

[sage-support] Re: Integration issue

2012-05-15 Thread Jason Grout
On 5/15/12 8:33 PM, Keshav Kini wrote: And maybe that's why plot3d(), unlike plot(), does seem to generate the deprecation warning. Sorry---what plot command doesn't generate a deprecation warning? Thanks, Jason -- To post to this group, send email to sage-support@googlegroups.com To

[sage-support] Re: Integration issue

2012-05-14 Thread kcrisman
This is now http://trac.sagemath.org/sage_trac/ticket/12947. We've had some issues with incomplete gamma functions translating properly in the past, and/or errors in Maxima, but I didn't have time to either look into that or whether there was another ticket open for this, apologies if there

[sage-support] Re: Integration issue

2012-05-14 Thread Robert Dodier
On 2012-05-14, kcrisman kcris...@gmail.com wrote: This is now http://trac.sagemath.org/sage_trac/ticket/12947. We've had some issues with incomplete gamma functions translating properly in the past, and/or errors in Maxima, but I didn't have time to either look into that or whether there

[sage-support] Re: Integration issue

2012-05-14 Thread John H Palmieri
On Sunday, May 13, 2012 8:46:41 PM UTC-7, ketchers wrote: Sage returns negative value for the integral of a positive function x*cos(x^3) on (0,0.5), if I use abs(cos(x^3))*x, then it gets it correct? This works for me: sage: numerical_integral(x*cos(x^3), 0, 0.5)

[sage-support] Re: Integration issue

2012-05-14 Thread JamesHDavenport
It may be branch cut strangeness, but if so it is very strange. The integrand is clearly well-behaved, and the integral, while in terms of the incomplete gamma function, seems to be off the usual branch cut (negative real axis). On Monday, 14 May 2012 15:35:01 UTC+1, Robert Dodier wrote: On

[sage-support] Re: Integration bug?

2012-03-29 Thread kcrisman
On Tuesday, March 27, 2012 4:25:48 PM UTC-4, david.guichard wrote: I've tried this on my 4.6 sage and on 5.0 beta; the main sagenb.org is not returning calculations for me. Both 4.6 and 5.0 have the same error. This double integral calculation is correct: var(r t)

[sage-support] Re: Integration

2011-02-08 Thread achrzesz
One can also use scipy (faster) or mpmath (very slow) sage: import scipy.integrate sage: scipy.integrate.dblquad(lambda x,y:abs(cos(x+y)),0,pi,lambda x: 0,lambda x:pi) (6.2831850310568189, 8.0696816340264377e-08) sage: n(2*pi) 6.28318530717959 sage: from mpmath import * sage: mp.dps = 50;

[sage-support] Re: Integration

2011-02-07 Thread BFJ
It's 2*pi since the integral of abs(cos(x+y)) from x=0 to pi is 2 (independent of y). But here's how you can get Sage to compute a numerical integral for you: sage: f = lambda y: numerical_integral( lambda x: abs(cos(x+y)), 0, pi )[0] sage: f(0.0001) 1.0001 sage: numerical_integral(

[sage-support] Re: Integration

2011-02-07 Thread Robert Dodier
On Feb 7, 12:00 pm, Francois Maltey fmal...@nerim.fr wrote: Santanu Sarkar a crit : How one can find integral abs(cos(x+y)) where x varies from 0 to pi and y varies from 0 to pi in Sage? You must help Sage (in fact Maxima bellow) for these integrals. The Maxima add-on package

[sage-support] Re: Integration of piecewise function

2009-12-13 Thread Eugene Goldberg
So... There is no solution? On Dec 9, 6:03 pm, Sand Wraith omegat...@gmail.com wrote: Does anyone know is this issue only for newest version? (may be I should use older version of sage) On 8 дек, 21:47, David Joyner wdjoy...@gmail.com wrote: Unfortunately, the piecewise class was written

Re: [sage-support] Re: Integration of piecewise function

2009-12-13 Thread David Joyner
I'm cc'ing Paul Butler who wrote that method. Paul, are you following this thread? On Sun, Dec 13, 2009 at 3:32 PM, Eugene Goldberg omegat...@gmail.com wrote: So... There is no solution? On Dec 9, 6:03 pm, Sand Wraith omegat...@gmail.com wrote: Does anyone know is this issue only for newest

[sage-support] Re: Integration of piecewise function

2009-12-09 Thread Sand Wraith
Does anyone know is this issue only for newest version? (may be I should use older version of sage) On 8 дек, 21:47, David Joyner wdjoy...@gmail.com wrote: Unfortunately, the piecewise class was written before the symbolic expressions class and has not kept pace. The obvious solution produced