Recent changes to 2546: solve with repeated equations gives a wrong answerhttps://sourceforge.net/p/maxima/bugs/2546/2013-05-24T02:12:24Z#2546 solve with repeated equations gives a wrong answer2013-05-24T02:12:24Z2013-05-24T02:12:24ZRobert Dodierhttps://sourceforge.net/u/userid-501686/https://sourceforge.netf2b5eaaabc4c170daebac0062e619488d26e72d9<div class="markdown_content"><ul>
<li><strong>labels</strong>: --> Lisp Core - Solving equations</li>
</ul></div>#2546 solve with repeated equations gives a wrong answer2013-02-16T16:47:25Z2013-02-16T16:47:25ZRupert Swarbrickhttps://sourceforge.net/u/rswarbrick/https://sourceforge.netf032c83d8b1f1f6f29b0b2729d17e75fc2ee6af5<div class="markdown_content"><p>I think this shows that we need to improve the documentation for solve(). An empty list as a return value means that solve couldn't find any solutions, not that none exist (this sort of gets written up in the documentation for algsys, but I agree that's not good enough)</p></div>#2546 solve with repeated equations gives a wrong answer2013-02-16T16:35:12Z2013-02-16T16:35:12ZDima Pasechnikhttps://sourceforge.net/u/dimpase/https://sourceforge.netf7da9efd032bb7f5ae91f438355a08c2f07e9f56<div class="markdown_content"><p>Well, in the case of two equations it returns an empty set, i.e. no solutions, right? This looks like a bug, no?</p></div>#2546 solve with repeated equations gives a wrong answer2013-02-16T16:07:40Z2013-02-16T16:07:40ZRupert Swarbrickhttps://sourceforge.net/u/rswarbrick/https://sourceforge.net2bc3263f0ab96b3af3caf78d4813edc91d1eacf5<div class="markdown_content"><p>Question on list at <a href="http://permalink.gmane.org/gmane.comp.mathematics.maxima.general/41206">http://permalink.gmane.org/gmane.comp.mathematics.maxima.general/41206</a></p></div>#2546 solve with repeated equations gives a wrong answer2013-02-16T15:55:12Z2013-02-16T15:55:12ZRupert Swarbrickhttps://sourceforge.net/u/rswarbrick/https://sourceforge.net89081e994f38393c8e75c5ea1aad0b6fccd7019e<div class="markdown_content"><p>What's going on is that we don't remove duplicate equations in $solve. Then we call SSOLVE on a single equation or SOLVEX on multiple equations. The two behave differently when they can't find a solution. I'm inclined to think that this behaviour is not a bug: after all, Maxima is failing to say anything useful in either case. I'll put a question to the mailing list about it in a second.</p></div>solve with repeated equations gives a wrong answer2013-02-11T14:34:06Z2013-02-11T14:34:06ZDima Pasechnikhttps://sourceforge.net/u/dimpase/https://sourceforge.net06909d61d3220f89069e4309549ace44cdef2723<div class="markdown_content"><p>With the release of Maxima (as well as with 5.29.1), one gets<br />
(%i1) solve(<span>[sin(x)=cos(x), sin(x)=cos(x)]</span>,x); <br />
(%o1) [] <br />
</p>
<p>(%i2) solve(<span>[sin(x)=cos(x)]</span>,x);<br />
(%o2) <span>[sin(x) = cos(x)]</span></p>
<p>That is, repeating an equation changes the result (to a wrong one, too)!</p></div>solve with repeated equations gives a wrong answer2013-02-11T14:34:06Z2013-02-11T14:34:06ZDima Pasechnikhttps://sourceforge.net/u/dimpase/https://sourceforge.netb540e0cf3cfbf9c9bb69e68ccca70040a254fb67<div class="markdown_content"><p>Ticket 2546 has been modified: solve with repeated equations gives a wrong answer<br />
Edited By: Robert Dodier (robert_dodier)</p></div>