#2558 to_poly_solve hangs

[Jean-Yves]

Hi,

When doing "to_poly_solve(6*cos(2*x+1)*(sin(2*x+1))^2,x)" Maxima hangs. Build_info is: build_info("5.28.0-2","2012-08-27 23:16:48","i686-pc-mingw32","GNU Common Lisp (GCL)","GCL 2.6.8").

Best regards,

Jean-Yves

[Robert Dodier]

Not observed in recent Maxima versions. Here's what I get:

(%i1) e : 6*cos(2*x+1)*(sin(2*x+1))^2 $
(%i2) load (to_poly_solve);
Loading maxima-grobner $Revision: 1.6 $ $Date: 2009-06-02 07:49:49 $
WARNING: DEFUN/DEFMACRO: redefining macro OPAPPLY in /usr/share/maxima/5.30.0/share/fourier_elim/fourier_elim.lisp, was defined in
         /usr/share/maxima/5.30.0/share/to_poly_solve/to_poly.lisp
WARNING: DEFUN/DEFMACRO: redefining macro OPCONS in /usr/share/maxima/5.30.0/share/fourier_elim/fourier_elim.lisp, was defined in
         /home/robert/tmp/rpmbuild/BUILD/maxima-5.30.0/src/binary-clisp/nummod.fas
(%o2)   /usr/share/maxima/5.30.0/share/to_poly_solve/to_poly_solve.mac
(%i3) display2d : false $  
(%i4) to_poly_solve (e, x);
(%o4) %union([x = (2*%pi*%z1+%pi-2)/4],
             [x = -(%i*(log((cos(1)^4/((sin(1)^2-cos(1)^2)^2
                                      +4*cos(1)^2*sin(1)^2)
                             -sin(1)^4/((sin(1)^2-cos(1)^2)^2
                                       +4*cos(1)^2*sin(1)^2))
                             ^2
                             +(-2*cos(1)*sin(1)^3
                              /((sin(1)^2-cos(1)^2)^2+4*cos(1)^2*sin(1)^2)
                              -2*cos(1)^3*sin(1)
                               /((sin(1)^2-cos(1)^2)^2+4*cos(1)^2*sin(1)^2))
                              ^2)
                       /2
                       +%i*(atan((-2*cos(1)*sin(1)^3
                                  /((sin(1)^2-cos(1)^2)^2+4*cos(1)^2*sin(1)^2)
                                  -2*cos(1)^3*sin(1)
                                   /((sin(1)^2-cos(1)^2)^2
                                    +4*cos(1)^2*sin(1)^2))
                                  /(-sin(1)^2*(sin(1)^2-cos(1)^2)
                                   /((sin(1)^2-cos(1)^2)^2
                                    +4*cos(1)^2*sin(1)^2)
                                   -cos(1)^2*(sin(1)^2-cos(1)^2)
                                    /((sin(1)^2-cos(1)^2)^2
                                     +4*cos(1)^2*sin(1)^2)))
                           -%pi))
                -2*%pi*%z8)
                /4])
(%i5) expand (float (%));
(%o5) %union([x = 1.570796326794897*%z1+.2853981633974483],
             [x = 1.570796326794897*%z8-2.775557561562891E-17*%i-0.5])
(%i6) subst (x=(2*%pi*%z1+%pi-2)/4, e);
(%o6) 6*cos((2*%pi*%z1+%pi-2)/2+1)*sin((2*%pi*%z1+%pi-2)/2+1)^2
(%i7) expand (%);
(%o7) 0
(%i8) subst (x = %pi/2 * %z8 - 1/2, e);
(%o8) 6*cos(2*(%pi*%z8/2-1/2)+1)*sin(2*(%pi*%z8/2-1/2)+1)^2
(%i9) expand (%);
(%o9) 0

Maxima version: "5.30.0"
Maxima build date: "2013-04-02 12:22:12"
Host type: "i486-pc-linux-gnu"
Lisp implementation type: "CLISP"
Lisp implementation version: "2.49 (2010-07-07) (built 3517450627) (memory 3573919336)"

[Jean-Yves]

I confirm it is working fine with Maxima 5.30.0 (sorry for the delay: it took me some time to find an up to date Windows version). By the way, Maxima is a great tool! Thanks a lot for bringing it to the community! I installed it on a small web site (www.lovemaths.fr) aimed at doing automatic studies of functions (to ease students' life).

Best regards,

Jean-Yves