From: SourceForge.net <no...@so...> - 2006-07-04 05:26:48
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Bugs item #681613, was opened at 2003-02-06 05:10 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=681613&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. >Category: Share Libraries Group: None Status: Open Resolution: None Priority: 5 Submitted By: Martin Rubey (kratt5) Assigned to: Nobody/Anonymous (nobody) Summary: 3 solver bugs Initial Comment: GCL (GNU Common Lisp) Version(2.5.0) Sun Nov 17 15:58:09 CET 2002 Licensed under GNU Library General Public License Contains Enhancements by W. Schelter Maxima 5.9.0rc3 http://maxima.sourceforge.net Distributed under the GNU Public License. See the file COPYING. Dedicated to the memory of William Schelter. This is a development version of Maxima. The function bug_report() provides bug reporting information. (C1) EquationP(e):=if part(e,0)="=" then true else false$ (C2) load("/usr/labri/rubey/maxima/src/binary-gcl/comm.o")$ (C3) load("/usr/labri/rubey/maxima/src/binary-gcl/mutils.o")$ (C4) load("/usr/labri/rubey/maxima/src/binary-gcl/set.o")$ (C5) load("algebra/solver/misc")$ (C6) load("algebra/solver/solver")$ (C7) display2d:false$ (C8) trace(solve)$ (C9) solver([u-t*(u^(l+1)+u+1) = 0,1-t*((l+1)*u^l+1) = 0],[u,t],[l]); 1 Enter SOLVE [(-l-1)*t*u^l-t+1,u] Is l an integer? y; 1 Exit SOLVE [u = (1/(l*t+t)-t/(l*t+t))^(1/l)] 1 Enter SOLVE [-((l*((-(t-1)/((l+1)*t))^(1/l)+1)+1)*t-l*(-(t-1)/((l+1)*t))^(1/l))/(l+1),t] 1 Exit SOLVE [t = l*(-(t-1)/((l+1)*t))^(1/l)/(l*(-(t-1)/((l+1)*t))^(1/l)+l+1)] (D9) [[u = (-(t-1)/((l+1)*t))^(1/l), [-((l*((-(t-1)/((l+1)*t))^(1/l)+1)+1)*t-l*(-(t-1)/((l+1)*t))^(1/l)) /(l+1)]]] (should be something like t = l^(l/(l+1))/(l^(l/(l+1))+l+1), u = l^(-1/(l+1))) The second item of the solution does not make t explicit, although solve did... 2. second bug (I think this is known, but I'm not sure) the second time solver is invoked, it is silently assumed that l is an integer. I think this assumption should be removed... 3. third bug don't use i or k as one of your variables: (C1) EquationP(e):=if part(e,0)="=" then true else false$ (C1) (C2) load("/usr/labri/rubey/maxima/src/binary-gcl/comm.o")$ (C3) load("/usr/labri/rubey/maxima/src/binary-gcl/mutils.o")$ (C4) load("/usr/labri/rubey/maxima/src/binary-gcl/set.o")$ (C5) load("algebra/solver/misc")$ (C6) load("algebra/solver/solver")$ (C7) display2d:false$ (C8) trace(solve)$ (C9) solver([u-t*(u^(k+1)+1)=0,1-(k+1)*t*u^k=0],[u,t]); 1 Enter SOLVE [(-k-1)*t*u^k+1,t] 1 Exit SOLVE [t = 1/((k+1)*u^k)] Warning: GET(OP(EXPR),'Valuation) was declared mode FIXNUM, has value: FALSE 1 Enter SOLVE [(2*u^3-1)/(3*u^2),u] ******* obviously, this is wrong here ******** who set k=2 ??? This might have to do with dynamic scope - in valuationsolver k is used, and if I leave away the parameter k, i get the following message: Warning: GET(OP(EXPR),'Valuation) was declared mode FIXNUM, has value: FALSE *********************************************** 1 Exit SOLVE [u = (SQRT(3)*%I-1)/(2*2^(1/3)),u = -(SQRT(3)*%I+1)/(2*2^(1/3)),u = 1/2^(1/3)] (D9) [[u = (SQRT(3)*%I-1)/(2*2^(1/3)), t = 2^(4*k/3)/((SQRT(3)*%I-1)^k*k+(SQRT(3)*%I-1)^k)], [u = -(SQRT(3)*%I+1)/(2*2^(1/3)), t = 2^(4*k/3)/((-SQRT(3)*%I-1)^k*k+(-SQRT(3)*%I-1)^k)], [u = 1/2^(1/3),t = 2^(k/3)/(k+1)]] ********************* similar trouble for i ********************* (C10) solver([u-t*(u^(i+1)+1)=0,1-(i+1)*t*u^i=0],[u,t],[i]); 1 Enter SOLVE [(-i-1)*t*u^i+1,t] 1 Exit SOLVE [t = 1/((i+1)*u^i)] 1 Enter SOLVE [(i*u^(i+1)-1)/((i+1)*u^i),u] Is i an integer? y; 1 Exit SOLVE [u = 1/i^(1/(i+1))] (D10) [[u = 1,t = 1/2]] (with l in place of i or k the result is correct: solver([u-t*(u^(l+1)+1)=0,1-(l+1)*t*u^l=0],[u,t],[l]); (D15) [[u = 1/l^(1/(l+1)),t = l^(l/(l+1))/(l+1)]] Martin ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=681613&group_id=4933 |