<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello,<div><br></div><div>To do the symbolic differentiation, I created a new class, that store the dependencies with respect to a symbol (or many) and the degree of differentiation. </div><div><br></div><div>Then I can differentiate the symbol (add 1 to the degree). and at the end I can make the substitution and the real differentiation.</div><div><br></div><div> I'm not sure that is the correct approach, but it works for me.</div><div><br></div><div>Felipe.</div><div><br></div><div><br></div><div><div><div>Le 22 juil. 12 à 19:29, Martin Ettl a écrit :</div><br class="Apple-interchange-newline"><blockquote type="cite"><div class="gmail_quote">Hello,<div><br></div><div>i have a question regarding symbolic differentiation with GiNAC.</div><div><br></div><div>Here is what i am trying to do:</div><div><br></div><div>I have to variables a(t) and b(t), both are dependent from time (t). </div> <div>Suppose, this two variables are multiplied liked this:</div><div><br></div><div> a(t) * b(t)</div><div><br></div><div>Is it possible to derive this expression (a(t)*b(t)) according time with ginac.</div> <div> <br></div><div>The only function i found in the manual is usefull for partial derivation, which does not help me here.</div><div><br></div><div><br></div><div>Here is some example code:</div><div><br></div><div> symbol a("a"), b("b"); // <-- how to tell ginac that variable a and b is dependant from variable t</div> <div> expression f = a*b;</div><div> std::cout << f.diff(t,1) << std::endl;</div><div><br></div><div><br></div><div>Many thanks in advance and best regards</div><span class="HOEnZb"><font color="#888888"><div> <br></div><div>Martin Ettl </div><div><br></div> <div><br></div> </font></span></div><br> _______________________________________________<br>GiNaC-list mailing list<br><a href="mailto:GiNaC-list@ginac.de">GiNaC-list@ginac.de</a><br>https://www.cebix.net/mailman/listinfo/ginac-list<br></blockquote></div><br></div></body></html>