## maxima-discuss — Maxima discussion list

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Showing 13 results of 13

 Re: [Maxima-discuss] matrixexp From: Iai Masafumi ax - 2014-03-19 22:24:27 ```Thank you guys for replies. It would have been obvious for everybody if the message was Proviso: assuming 4*(w3^2+w2^2+w1^2) not equal to 0 (2014/03/20 2:47), Barton Willis wrote: > >> Could you tell me the meaning of this warning message from matrixexp()? >> "Proviso: assuming 4*(w3^2+w2^2+w1^2) # 0" > > It means in the course of the calculation there was a division by w3^2+w2^2+w1^2. You might > notice that the denominators of exp(W) involve w3^2+w2^2+w1^2. You might like to try this: > > (%i62) limit(ratsubst(zzz, w3^2+w2^2+w1^2, expW),zzz,0); > (%o62) matrix([1,w3,-w2,w1],[-w3,1,w1,w2],[w2,-w1,1,w3],[-w1,-w2,-w3,1]) > > And I believe that this is correct: When w3^2+w2^2+w1^2, the matrix W is a negative root of unity > (W^2 + I = 0). > > >> >> Can I consider its result is reliable? >> >> The commands I entered are below: >> >> declare(w1, real); >> declare(w2, real); >> declare(w3, real); >> W:matrix([0, w3, -w2, w1], [-w3, 0, w1, w2], [w2, -w1, 0, w3], [-w1, >> -w2, -w3, 0]); >> expW:matrixexp(W); ```
 [Maxima-discuss] unkind error return from rk() with stiff o.d.e. From: Edwin Woollett - 2014-03-19 22:08:02 ```In a previous post, I complained about the "unkind" error return of rk(..) with a stiff o.d.e. (many pages of error messages). For an example of a "kind" return with a contributed method, use rkf45: --------------------------- (%i2) load(rkf45); (%o2) "C:/PROGRA~1/MAXIMA~3.2/share/maxima/5.31.2/share/contrib/rkf45/rkf45.mac" (%i9) stiff : rkf45([y2, 1000*y2*(1-y1^2) - y1],[y1,y2],[2,0],[t,0,30])\$ Warning: rkf45: Integration stopped at x = 8.7296685 (stiff problem?) Iterations limit has been reached. Check if differential equations/initial conditions are given correctly, reduce accuracy, and/or increase maximum number of steps. -------------------------------------------------- Ted Woollett ```
 Re: [Maxima-discuss] Mac and Windows From: Norman Beam - 2014-03-19 21:04:54 ```You can build Maxima, xMaxima, and wxMaxima from scratch with no knowledge of programming using MacPorts. You must be willing to install the OSX development tools (X11 and Xcode) which I think are both free currently. Start here https://www.macports.org/guide/#introduction for what you must install. It is a lot to download but once you do, keeping Maxima up-to-date is pretty easy. If you want to go this route, tell MacPorts to build wxMaxima and it will create everything you need, SBCL, GnuPlot, Maxima, xMaxima, wxMaxima, etc. Regards, Norman On 3/19/14 4:23 PM, Robert Dodier wrote: > On 2014-03-19, Erich Neuwirth wrote: > >> Is there any information if OSX and Windows binaries will be available for 5.32.1 in the near future? > I make the releases and source code bundle and binaries for Linux. > Unfortunately, I don't have a Windows or OSX development environment. > Binaries for those systems are contributed by others, and I don't > have a schedule for that. > > The good news is that for OSX, at least, I believe it is enough like a > conventional Un*xish system for Maxima's build machinery to work so > that you can build Maxima from source code. I don't know the details, > maybe someone can tell us. > > I have built Maxima from source code on Windows, and did get a working > executable, although maybe stuff around the edges (XMaxima / help / > plotting) might or might not have worked as expected. I can say more > about that if you're interested. > > Sorry I can't be more helpful, > > Robert Dodier > > > > ------------------------------------------------------------------------------ > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and their > applications. Written by three acclaimed leaders in the field, > this first edition is now available. Download your free book today! > http://p.sf.net/sfu/13534_NeoTech > _______________________________________________ > Maxima-discuss mailing list > Maxima-discuss@... > https://lists.sourceforge.net/lists/listinfo/maxima-discuss > ```
 Re: [Maxima-discuss] Mac and Windows From: Robert Dodier - 2014-03-19 20:24:19 ```On 2014-03-19, Erich Neuwirth wrote: > Is there any information if OSX and Windows binaries will be available for 5.32.1 in the near future? I make the releases and source code bundle and binaries for Linux. Unfortunately, I don't have a Windows or OSX development environment. Binaries for those systems are contributed by others, and I don't have a schedule for that. The good news is that for OSX, at least, I believe it is enough like a conventional Un*xish system for Maxima's build machinery to work so that you can build Maxima from source code. I don't know the details, maybe someone can tell us. I have built Maxima from source code on Windows, and did get a working executable, although maybe stuff around the edges (XMaxima / help / plotting) might or might not have worked as expected. I can say more about that if you're interested. Sorry I can't be more helpful, Robert Dodier ```
 Re: [Maxima-discuss] matrixexp From: Barton Willis - 2014-03-19 17:47:39 ```> Could you tell me the meaning of this warning message from matrixexp()? > "Proviso: assuming 4*(w3^2+w2^2+w1^2) # 0" It means in the course of the calculation there was a division by w3^2+w2^2+w1^2. You might notice that the denominators of exp(W) involve w3^2+w2^2+w1^2. You might like to try this: (%i62) limit(ratsubst(zzz, w3^2+w2^2+w1^2, expW),zzz,0); (%o62) matrix([1,w3,-w2,w1],[-w3,1,w1,w2],[w2,-w1,1,w3],[-w1,-w2,-w3,1]) And I believe that this is correct: When w3^2+w2^2+w1^2, the matrix W is a negative root of unity (W^2 + I = 0). > > Can I consider its result is reliable? > > The commands I entered are below: > > declare(w1, real); > declare(w2, real); > declare(w3, real); > W:matrix([0, w3, -w2, w1], [-w3, 0, w1, w2], [w2, -w1, 0, w3], [-w1, > -w2, -w3, 0]); > expW:matrixexp(W); ```
 Re: [Maxima-discuss] matrixexp From: Gunter Königsmann - 2014-03-19 17:30:46 Attachments: Message as HTML ```Macima actually understand the hash sign (#) as sign for "not equal". Since every programming language uses a different symbol here it seems like there is no standard method in specifying inequality using ASCII characters. On 19. März 2014 17:05:37 MEZ, Przemek Klosowski wrote: >On 03/19/2014 05:08 AM, Iai Masafumi ax wrote: >> Could you tell me the meaning of this warning message from >matrixexp()? >> >> "Proviso: assuming 4*(w3^2+w2^2+w1^2) # 0" >> >> Can I consider its result is reliable? >> >> The commands I entered are below: >> >> declare(w1, real); >> declare(w2, real); >> declare(w3, real); >> W:matrix([0, w3, -w2, w1], [-w3, 0, w1, w2], [w2, -w1, 0, w3], [-w1, >> -w2, -w3, 0]); >> expW:matrixexp(W); >The expression (2*w3**2+2*w2**2+2*w1**2) appears in the denominator of >the solution, so the Proviso warns you that the solution is undefined >when 4*(w3^2+w2^2+w1^2) is equal to 0. I agree that the use of # to >signify 'unequal to' is quirky---I don't think Maxima uses it as such >(I >am sure I will be corrected if I am wrong about that). > > >------------------------------------------------------------------------ > >------------------------------------------------------------------------------ >Learn Graph Databases - Download FREE O'Reilly Book >"Graph Databases" is the definitive new guide to graph databases and >their >applications. Written by three acclaimed leaders in the field, >this first edition is now available. Download your free book today! >http://p.sf.net/sfu/13534_NeoTech > >------------------------------------------------------------------------ > >_______________________________________________ >Maxima-discuss mailing list >Maxima-discuss@... >https://lists.sourceforge.net/lists/listinfo/maxima-discuss -- Diese Nachricht wurde von meinem Android-Mobiltelefon mit K-9 Mail gesendet.```
 Re: [Maxima-discuss] matrixexp From: Przemek Klosowski - 2014-03-19 16:05:51 Attachments: Message as HTML ```On 03/19/2014 05:08 AM, Iai Masafumi ax wrote: > Could you tell me the meaning of this warning message from matrixexp()? > > "Proviso: assuming 4*(w3^2+w2^2+w1^2) # 0" > > Can I consider its result is reliable? > > The commands I entered are below: > > declare(w1, real); > declare(w2, real); > declare(w3, real); > W:matrix([0, w3, -w2, w1], [-w3, 0, w1, w2], [w2, -w1, 0, w3], [-w1, > -w2, -w3, 0]); > expW:matrixexp(W); The expression (2*w3**2+2*w2**2+2*w1**2) appears in the denominator of the solution, so the Proviso warns you that the solution is undefined when 4*(w3^2+w2^2+w1^2) is equal to 0. I agree that the use of # to signify 'unequal to' is quirky---I don't think Maxima uses it as such (I am sure I will be corrected if I am wrong about that). ```
 [Maxima-discuss] Mac and Windows From: Erich Neuwirth - 2014-03-19 12:10:16 Attachments: signature.asc ```Is there any information if OSX and Windows binaries will be available for 5.32.1 in the near future? ```
 Re: [Maxima-discuss] matrixexp From: Helmut Jarausch - 2014-03-19 11:37:14 ```On 03/19/2014 10:08:12 AM, Iai Masafumi ax wrote: > Hi, > > Could you tell me the meaning of this warning message from > matrixexp()? > > "Proviso: assuming 4*(w3^2+w2^2+w1^2) # 0" > > Can I consider its result is reliable? > > The commands I entered are below: > > declare(w1, real); > declare(w2, real); > declare(w3, real); > W:matrix([0, w3, -w2, w1], [-w3, 0, w1, w2], [w2, -w1, 0, w3], [-w1, > -w2, -w3, 0]); > expW:matrixexp(W); > > factor(determinant(W)); gives (w3^2+w2^2+w1^2)^2, so Maxima assumes that W is a regular matrix. I don't know the internals of matrixexp, but the warning states that the result is OK unless W is singular. Helmut ```
 [Maxima-discuss] about Sound package From: 有坂富雄 - 2014-03-19 11:34:47 Attachments: text/plain ```Hello, I found a Sound package made by Mario recently. ; It is useful for me. Thanks a lot. By the way, I had some minor troubles using the sound package. So, I fixed them as follows. 1. \$sound_sample_list function does not work with a Lisp error.    I fixed it (for SBCL). 2. The option player = "open -a" does not work,     because it doesn't accept long directory names with spaces    or adding command-options.    I fixed it.    My solution is that I put a command-path in double-quotes    and I add \$player_options to divide the player-command     between a command-path and command-options. 3. \$wxplay function is added for wxMaxima.     (and always draws the waveform when it is called) For example: When I play sounds on Mac OS X, I call the next command using a terminal. ('QuickTime Player.app' is a music & movie player built in Mac OS X.) open -a '/Applications/QuickTime Player.app' ~/maxout.wav So, I set the following options and play sounds with wxMaxima. load("~/sound.lisp")\$ set_sound_defaults(    player         = "open",    player_options = "-a '/Applications/QuickTime Player.app'",    draw_wave_options = [dimensions = [800,200]] )\$ wxplay(    file_name = "sound-out",    envelope = adsr(0.01, 0.1, 0.8, 0.4),    attenuation_coef = [1,1/2,1/3],    note(440,1000,0.5,0,0.6,1.2)) \$ Another player options like following is allowed:    player = "/usr/bin/open"    player = "~/maxima/A Maxima Sound package/playsound" My environment: Mac OS X 10.6.8 wxMaxima 13.04.0 Maxima 5.30.0 SBCL 1.0.55.0 The difference from the original sound.lisp is attached to this mail. I hope you will enjoy playing Maxima with Mario's sound package. Thanks. Tomio P.S. I made the difference from an original sound.lisp as follows. \$ diff ./sound.lisp ./sound_fixed_by_me.lisp > ./sound.lisp.diff Then you can make a patched one as follows. \$ patch ./sound.lisp ./sound.lisp.diff ```
 [Maxima-discuss] matrixexp From: Iai Masafumi ax - 2014-03-19 09:24:33 ```Hi, Could you tell me the meaning of this warning message from matrixexp()? "Proviso: assuming 4*(w3^2+w2^2+w1^2) # 0" Can I consider its result is reliable? The commands I entered are below: declare(w1, real); declare(w2, real); declare(w3, real); W:matrix([0, w3, -w2, w1], [-w3, 0, w1, w2], [w2, -w1, 0, w3], [-w1, -w2, -w3, 0]); expW:matrixexp(W); Thanks, Iai ```
 Re: [Maxima-discuss] some things maxima can't do (yet) but macsyma can From: Thomas D. Dean - 2014-03-19 05:47:40 ```On 03/18/14 20:44, Richard Fateman wrote: > ratdisrep(%) on the taylor series. > > and then rat(%) to get a polynomial in sqrt(h). > > taytorat(%) does this. Continuing from above, eq30:taytorat(eq6); eq31:subst(h=X^2,taytorat(eq6)); find_root(eq31,X,0,1000); %^2; /* this is the root, 1278.338987998867, now solve eq31... */ eq32:eq31,assume(X>0); eq33:num(eq32); I guess this is too difficult to do other than numerically... Maple 11 returns a high degree RootOf expression. Tom Dean ```
 Re: [Maxima-discuss] some things maxima can't do (yet) but macsyma can From: Thomas D. Dean - 2014-03-19 03:30:57 ```On 03/17/14 13:02, Richard Fateman wrote: > and for a fun read, see > > http://gosper.org/newsrope.pdf > I played with this, some. /* Let h be the unknown height, r the radius of the earth, and 2*%pi the slack (permitting an all around elevation of , e.g., 3ft.). Let alpha be the angle at the center of the earth between the hoist point and the ropes tangency at the "horizon". Then the equations are */ kill(all); load(revert); eq1:r/(r+h) = cos(alpha); /* Triangle from tangent point to hoist point */ l1:r*tan(alpha); /* length from tangent point to hoist point */ a1:2*r*alpha; /* length of arc under half the hoisted rope */ a2:2*r*%pi; /* circumference of earty */ l2:2*%pi*(r+epsilon); /* total length of rope */ eq2:2*l1 + (a2-a1) = l2; eq3:subst(solve(eq1,alpha),eq2); eq4:solve(eq3,epsilon); eq5:subst([epsilon=3,r=3959*5280],eq4); eq6:taylor(rhs(first(eq5-3)),h,0,4); How do I get from /T/ to polynomial? eq8:rhs(first(eq5-3)); plot2d(eq8,[h,-10000,10000]); plot2d(eq8,[h,0,2500]); nsoln:find_root(eq8,h,1200,1300); Tom Dean ```

Showing 13 results of 13