[Maxima-bugs] [ maxima-Bugs-3467526 ] expintegral_e: series failed.

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Bugs item #3467526, was opened at 2011-12-30 10:37
Message generated for change (Comment added) made by woollett
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Ted Woollett (woollett)
Assigned to: Nobody/Anonymous (nobody)
Summary: expintegral_e: series failed.

Initial Comment:
float or bfloat of gamma_incomplete fails if second arg is large imag. number.
--------------------------------
Maxima 5.25.1 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL)

(%i1) fpprintprec:8$

(%i2) block([fpprec:20],bfloat(gamma_incomplete(0,10*%i*log(2))));

(%o2) -1.2240361b-1*%i-6.9062484b-2

(%i3) block([fpprec:20],bfloat(gamma_incomplete(0,100*%i*log(2))));

(%o3) 4.5615238b6*%i-5.0797908b5

(%i4) block([fpprec:20],bfloat(gamma_incomplete(0,1000*%i*log(2))));

(%o4) 5.623594b274-1.2330921b276*%i

(%i5) block([fpprec:20],bfloat(gamma_incomplete(0,10000*%i*log(2))));

expintegral_e: series failed.
 -- an error. To debug this try: debugmode(true);

/*I am actually interested in being able to compute
the integral */

(%i6) integrate(integrate(cos(x*y*log(2)),y,1,10^4),x,1,10^4);

(%o6) -(%i*gamma_incomplete(0,100000000*%i*log(2))
       -2*%i*gamma_incomplete(0,10000*%i*log(2))
       +%i*gamma_incomplete(0,%i*log(2))-%i*gamma_incomplete(0,-%i*log(2))
       +2*%i*gamma_incomplete(0,-10000*%i*log(2))
       -%i*gamma_incomplete(0,-100000000*%i*log(2))) /(2*log(2))
/* which involves 10^8*%i*log(2)  */

Ted Woollett


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>Comment By: Ted Woollett (woollett)
Date: 2011-12-30 14:06

Message:
Maxima version: 5.25.1
Maxima build date: 10:2 9/6/2011
Host type: i686-pc-mingw32
Lisp implementation type: GNU Common Lisp (GCL)
Lisp implementation version: GCL 2.6.8

Ted Woollett

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3467526&group_id=4933