From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,a9b0810d3106d9b8 X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII Path: g2news2.google.com!news3.google.com!feeder.news-service.com!2a02:590:1:1::196.MISMATCH!news.teledata-fn.de!newsfeed.arcor.de!newsspool4.arcor-online.net!news.arcor.de.POSTED!not-for-mail From: "Dmitry A. Kazakov" Subject: Re: Fun with C Newsgroups: comp.lang.ada User-Agent: 40tude_Dialog/2.0.15.1 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Reply-To: mailbox@dmitry-kazakov.de Organization: cbb software GmbH References: <4b5748dc-60fa-4cec-a317-054626e9a1ca@d19g2000prh.googlegroups.com> <1hnl95prvrt6i$.1s675gncbjxsu$.dlg@40tude.net> <5d44db50-ceff-4f4d-8bc7-714f31fbca06@hd10g2000vbb.googlegroups.com> <1uthrsrabx8di$.8i74uk28axo0.dlg@40tude.net> <84b83223-e191-4912-8f73-318deb4dd783@d19g2000prh.googlegroups.com> <1j2bi0982bjcs.1beq9xn9za9yb$.dlg@40tude.net> <9j18r6hrlf06adfv4rdothhdrjmfdrmeno@4ax.com> <1qe52ny88vlk9$.hcf0wgd0xcmh.dlg@40tude.net> <117x5uepxzqrn$.zu65rz3wdey9.dlg@40tude.net> <10wrcep2z88z3$.1q3jmf2y5a0qn.dlg@40tude.net> <356b1c5c-9b6e-488b-a31a-6e1d15082f2c@k22g2000yqh.googlegroups.com> <5l0ijm901fhp$.3f2xu562o6ri$.dlg@40tude.net> <724c7fd3-046b-42ee-9dff-5606b8ca1048@dr5g2000vbb.googlegroups.com> Date: Thu, 28 Apr 2011 09:41:51 +0200 Message-ID: <1ttincqpi28n0.1no79n6bocser.dlg@40tude.net> NNTP-Posting-Date: 28 Apr 2011 09:41:48 CEST NNTP-Posting-Host: f2ae542d.newsspool2.arcor-online.net X-Trace: DXC=9^en8FPhM_1NTD55K=A9EHlD;3Yc24Fo<]lROoR18kF[0 X-Complaints-To: usenet-abuse@arcor.de Xref: g2news2.google.com comp.lang.ada:20039 Date: 2011-04-28T09:41:48+02:00 List-Id: On Thu, 28 Apr 2011 00:02:36 -0700 (PDT), Maciej Sobczak wrote: > On Apr 27, 10:00�am, "Dmitry A. Kazakov" > wrote: > >>>>> What? A simple hanging spring can oscillate while being purely linear. > >> No, I mean that x(t) =A sin(2Pi f t) + x0 is not a linear function of time. > > You got it backwards. Completely. > > The above equation does not define the spring mechanics. It is not an equation, it is a solution of some second-order differential equation [equations themselves can be linear or not, which is unrelated to the issue]. > It only describes the *observable effect* of this mechanics. BTW, the only effects are the observable ones. > The above program is a discrete simulator of a purely linear system. No, what you gave was a numeric solution of the differential equation. Whatever technique used to solve it, that does not change the nature of the system, obviously. (Numeric solutions are not only non-linear, they are not continuous) > The sine function is never used there and the program has no freaking > idea that it should oscillate in a harmonic way. Where you saw a program that used the sine function? There is no such thing on digital computers, only approximations of. What a surprise, these approximations use +, -, *, / math and rational numbers! Does it make sine, rational, linear? No. > In which case I still don't understand what you have failed to prove. > But hey, at least the discussion is related to Ada again. :-) Indeed. My thesis is no need to know C in order to learn Ada! -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de