http://blog.gmane.org/gmane.comp.mathematics.maxima.general hourly 1 1901-01-01T00:00+00:00 http://gmane.org/img/gmane-25t.png http://gmane.org http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42386 <pre>Hi, I've been messing around trying to reproduce some results in a paper I was reading. With pen and paper, I get a subtly different answer to the authors, but the calculation is unpleasant, so I thought I'd try to use Maxima to make sure I hadn't messed up the arithmetic. My problem is that I have expressions with stuff that's maybe of the form: exp(%i*n*T*w + %i*%pi*x) Maybe I know that T*w = 2*%pi (time and "angular speed"), so I can transform that to exp(%i*n*2*%pi + %i*%pi*x) I can tell Maxima that n is an integer, but how do can I get Maxima to figure out that the expression is equal to exp(%i*%pi*x)? The expressions I actually have to deal with are a bit bigger, but I don't think it changes the fundamental question. (And they contain terms of this form, with an integer times 2*%pi*%i plus something else in the exponent) Defrule-based incantations don't seem to be working for me. I also found the %emode flag in the documentation, but it doesn't seem to have any effect. (Bug?) Rupert _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Rupert Swarbrick 2013-05-23T11:31:48 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42380 <pre>Dear All, I am using the function dgeev to find the eigenvalues and eigenvectors of a 21x21 matrix. Can anyone tell me if dgeev normalizes the eigenvectors? If not is there another function to do this or do I need to write my own? Thanks, Ben _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Ben Blomberg 2013-05-23T05:17:24 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42376 <pre>Hello, I get an error with 5.30.0 which I don't get with 5.29.0 (or previous versions): Maxima 5.30.0 http://maxima.sourceforge.net using Lisp ECL 11.1.1 Distributed under the GNU Public License. See the file COPYING. Dedicated to the memory of William Schelter. The function bug_report() provides bug reporting information. (%i1) a:make_array(fixnum,3); Evaluation took 0.0000 seconds (0.0000 elapsed) (%o1) "{Lisp Array: #(0 0 0)}" (%i2) L:buildq([a], lambda([x],a[x])); Evaluation took 0.0000 seconds (0.0000 elapsed) Maxima encountered a Lisp error: In function SYMBOL-PLIST, the value of the first argument is #(0 0 0) which is not of the expected type SYMBOL Automatically continuing. To enable the Lisp debugger set *debugger-hook* to nil. Wrapping an array in a lambda-term is used quite a bit by us, and I think it should work? Best Oliver </pre> Oliver Kullmann 2013-05-22T19:09:23 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42372 <pre> I have recently become attached to using utf8 characters in my maxima code, which works great with sbcl. But both ecl and gcl choke, at least when fed from the maxima repl. So, I wonder if someone can explain to me the following behaviour: Maxima 5.30.0 http://maxima.sourceforge.net using Lisp GNU Common Lisp (GCL) GCL 2.6.7 (a.k.a. GCL) Distributed under the GNU Public License. See the file COPYING. Dedicated to the memory of William Schelter. The function bug_report() provides bug reporting information. (%i1) ρ:1; incorrect syntax: \201 is not an infix operator \317\201 ^ (%i1) :lisp (msetq $ρ 1) 1 (%i1) :lisp $ρ 1 Leo (The utf8 character is Greek Small Letter Rho, Hex c1) _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Leo Butler 2013-05-22T17:53:41 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42362 <pre>There is some difference between when a tellsimp rule is applied. Maybe the "and may not work" warning is relevant? (%i1) tellsimp(b+1,z); tellsimp: warning: putting rules on '+' or '*' is inefficient, and may not work. (%o1) [+rule1,simplus] (%i2) tellsimp(2*b,42); tellsimp: warning: putting rules on '+' or '*' is inefficient, and may not work. (%o2) [*rule1,simptimes] OK-- Maxima automatically simplifies 2*b to 42 (%i3) 2*b; (%o3) 42 Not OK -- b+1 isn't automatically simplified to z: (%i4) b+1; (%o4) b+1 (%i5) expand(%,0,0); (%o5) z --Barton _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Barton Willis 2013-05-22T10:40:31 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42361 <pre>Hello: I have written an article, "Minimal Maxima Revisited", which is an elaboration of the "Minimal Maxima" article written by Robert Dodier. It should probably be called "Medium Maxima" or something like that. In any case I would like to find a way to send it to Robert Dodier for his perusal and if there are no objections, offer this for inclusion with the list of "tutorial" or other documents of the Maxima project web site If there is an interest please reply with the method I should use to send this to those that are involved with the project web site. Thanks. David E. Miller </pre> David E. Miller 2013-05-20T22:40:34 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42356 <pre>I think I've made some progress on computing derivatives of sums and sums of kron_delta. It is doubtless possible to find bugs in this but all the same I think it's an improvement. I've attached the code. Here is an example session. (%i1) display2d : false $ (%i2) load ("sum_kron_delta.mac") $ (%i3) load ("diff_sum.mac") $ (%i4) 'sum ('diff ('sum (A[i]*x[i]^2, i, 1, n), x[j]), j, 1, n); (%o4) 2*'sum(if true then x[j]*A[j] else 0,j,1,n) (%i5) ''%; (%o5) 2*'sum(x[j]*A[j],j,1,n) (%i6) 'diff ('sum (u[k - 1] * u[k] * u[k + 1], k, 1, m), u[l]); (%o6) 'diff('sum(u[k-1]*u[k]*u[k+1],k,1,m),u[l],1) (%i7) ''%; (%o7) 'sum(u[k-1]*u[k]*kron_delta(k+1,l)+u[k-1]*kron_delta(k,l)*u[k+1] +kron_delta(k-1,l)*u[k]*u[k+1],k,1,m) (%i8) declare (sum, linear) $ (%i9) ''%o7; (%o9) (if 1 &lt;= l+1 and l+1 &lt;= m and %elementp(l+1,integers) then u[l+1]*u[l+2] else 0) +(if 1 &lt;= l and l &lt;= m and %elementp(l,integers) then u[l-1]*u[l+1] else 0) +(if 1 &lt;= l-1 and l-1 &lt;= m and %elementp(l-1,integers) then u[l-2]*u[l-1] else 0) (%i10) declare (l, integer); (%o10) done (%i11) assume (0 &lt;= l and l &lt;= m + 1) $ (%i12) ''%o7; (%o12) (if l+1 &lt;= m then u[l+1]*u[l+2] else 0) +(if 1 &lt;= l and l &lt;= m then u[l-1]*u[l+1] else 0) +(if 1 &lt;= l-1 then u[l-2]*u[l-1] else 0) I threw in a little bit of stuff for simplifying set operations -- I'm inclined to think all set operations should be simplifications, but I'll push that agenda another day. Thanks to Stavros and Michael Valenzuela and everybody who has expressed interest in this topic over the past few years. best Robert Dodier _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Robert Dodier 2013-05-21T16:26:53 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42355 <pre>I have the same observation on my worksheets. So what I do is after I evaluate everything I export that to a HTML so I have all images and the symbolics, numerics as well. Unfortunately the editable worksheet will always just give you the links the image path and filename and thats it. So in a way we could say that it does not really "embeds" the image. This maybe a known limitation we probably need to accept. Its easily done in MathCAD and is truly embedded but thats commercial stuff. Regards, Berns B. _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Berns Buenaobra 2013-05-21T08:11:44 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42349 <pre>The wxMaxima "Insert Image" command is causing me some confusion. I am assuming that "insert image" creates a link to a .png file which would then be displayed upon opening the session file (.wxm) for additional work. Upon opening the .wxm file and issuing "evaluate all cells" wxMaxima displays a text field with the .png file name from "insert image" command but not the image. I would appreciate help in understanding how "insert image" works. I am using Windows Vista Business with wxMaxima 12.04.0, and Maxima 5.28 </pre> Ronald Modesitt 2013-05-19T13:11:31 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42348 <pre>I have a idea (combined previous) expcontract(_expr):=block([_z], exp_log_to_power(_e):= block([_s, logconcoeffp: lambda([_s],true)], logcontract(_e)), logexpand: super, scanmap(lambda([_z],if atom(_z) then _z else ( exp_log_to_power(exp(logcontract(log(_z)))) )),_expr) )$ expr: x^a*y^a$ expcontract(expr); -&gt; (x*y)^a expr: (a^d*b^d+c^a*a^a)/(d^b*e^b+a^b*c^b)$ expcontract(expr); -&gt; ((a*b)^d+(a*c)^a)/((d*e)^b+(a*c)^b) Derka </pre> Derka Ladislav 2013-05-18T18:23:12 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42345 <pre> I was looking at a message from Harry Christhian[1] about a bug in integration, which I didn't quite understand, but I found the following serious error: (%i1) integrate(c/x^n,x); Is n - 1 zero or nonzero? nonzero; (%o1) c log(x) It doesn't matter whether you answer zero or nonzero; you get the answer as if n = 1. Ray [1] Is it possible to directly send email to maxima-bugs? Or should only the bug tracker send email to that list? Anyway, I think he's saying integrate(c/x^n,x) returns -c/(1-n)*x^(1-n) but he wants -c/(n-1)/x^(n-1). </pre> Raymond Toy 2013-05-19T16:42:57 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42342 <pre>Is there a maxima command that can make that simplification? Simplifying x^a*y^ato (x*y)^a, Essentially radcan in reverse Thanks DMD </pre> Dominic Di Toro 2013-05-17T16:14:17 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42340 <pre>Hello, I try multiply matrices, but te result is strange to me, see (%i1) matrix_element_mult: "."; (%o1) . (%i2) matrix([A],[0],[0]) . matrix([W]) . matrix([E]); [ A ] [ ] (%o2) [ 0 ] . W . E [ ] [ 0 ] Why above result is not expanded? If I use braces around (see below) then it works as expected, why? Is it a bug? What is the reason for this behavior? (%i3) (matrix([A],[0],[0]) . matrix([W])) . matrix([E]); [ A . W . E ] [ ] (%o3) [ 0 ] [ ] [ 0 ] This not work (%i4) expand(matrix([A],[0],[0]) . matrix([W]) . matrix([E])); [ A ] [ ] (%o4) [ 0 ] . W . E [ ] [ 0 ] Zbigniew </pre> Zbigniew Komarnicki 2013-05-17T19:41:08 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42339 <pre>Is there a maxima command that can make this simplification? Simplifying x^a*y^ato (x*y)^a, Essentially radcan in reverse Thanks DMD </pre> Dominic Di Toro 2013-05-17T16:19:33 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42312 <pre>Hello, I have equation e1: (a*x(l,p-1)-b*x(l-1,p-1))*C3+(a*x(l+1,p-1)-b*x(l,p-1))*C2 +(a*x(l+2,p-1)-b*x(l+1,p-1))*C1+(a*x(l,p)-b*x(l-1,p))*B3 +(a*x(l+1,p)-b*x(l,p))*B2+(a*x(l+2,p)-b*x(l+1,p))*B1 +(a*x(l,p+1)-b*x(l-1,p+1))*A3+(a*x(l+1,p+1)-b*x(l,p+1))*A2 +(a*x(l+2,p+1)-b*x(l+1,p+1))*A1; I need to collect terms around variable 'x( , )'. I do it in the following way: Make needed terms Lx: flatten( makelist([x(l+3-i,p+1), x(l+3-i,p), x(l+3-i,p-1)], i,1,3)); and then put it by hand to 'ratsimp' e2: ratsimp(e1, Lx[1], Lx[2], Lx[3], Lx[4], Lx[5], Lx[6], Lx[7], Lx[8], Lx[9]); It works, but is very tedious writing every Lx[i], i=1,..,9. Is it maybe possible to make it in the following way: /* this of course does not work - do not collect around x( , ) */ e2: ratsimp(e2, Lx); giving a whole list 'Lx' at once or how to make sequence of arguments Lx[1],...,Lx[9] to 'ratsimp' ? Is there a better solution to this problem? Thank you in advance. Zbigniew </pre> Zbigniew Komarnicki 2013-05-15T13:29:00 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42310 <pre>I happened to look at Arnold-Trivium-1991.pdf again last night, and tried the limit therein in maxima to see how well it would do. It took about 20 minutes of CPU time using sbcl. (A url to the pdf was posted some time ago in, I think, math-fun.) (%i1) f : (sin(tan(x))-tan(sin(x)))/(asin(atan(x))-atan(asin(x))); (%i2) limit(f,x,0); It returned 1. Which looks right, given plot2d(f,[x,-1,1]). Is it expected that maxima would take so long to calculate such a limit? -JimC </pre> James Cloos 2013-05-15T10:50:43 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42306 <pre>I have an interest in being able to do useful symbolic and numeric calculations with logarithms in base 10. I know there is a contrib module called log10. It works fine for doing numeric calculations, but doesn't behave how I'd like for generic symbolic manipulation. For example the natural log can solve for x: (%i1) solve(y=log(x),x); (%o1) [x=%e^y] But log10 gives this: (%i2) solve(y=log10(x),x); (%o2) [log10(x)=y] /* I'd prefer to get x=10^y */ There are many of other examples of symbolic manipulation of log10 where log shows up in the answer. I'd really like to leave log out of it altogether. It would be really handy if I could teach Maxima the various properties of logarithms and inverse logarithms. My interest is base 10, but it seems that it would be fairly generic for other integer bases. I don't even know where to start, but suggestions are welcome. Thanks in advance, Bill Eaton _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Bill Eaton 2013-05-15T00:46:21 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42298 <pre>So, as Maxima for Windows approaches a year since its last 'refresh', was wondering if there is a canonical reference as to the steps for 'rolling our own' (i.e., compiling not only Maxima, but the installer). Beyond the ignominy of actually being 'behind the Mac version' ;-), there are some practical needs for a refresh. The fact that it hasn't been done in ~10 months suggests the compilation is non-trivial (what my shop calls 'brittle' - stand on left foot, close eyes, face north, and type 'make', and hope it works), but I suspect there are several folks out there (or is it here) who would be willing to give it a shot. _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Evan Cooch 2013-05-14T13:44:20 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42296 <pre>OK, I've got maxima 5.30.0 up and running. Nice. What I want to do is define a function t(x) = f(a) + f'(a)(x-a) + f''(a)(x-a)^2/2 + f'''(a)(x-a)^3/6 + ... that is, a Taylor series, but so that t(b), for example, produces f(a) + f'(a)(b-a) + f''(a)(b-a)^2/2 + f'''(a)(b-a)^3/6 + ... with the derivatives still in terms of x. This is what happens at the moment: (%i1) t(x):=taylor(f(x),x,a,6); (%i2) t(b); and the derivatives now are all in terms of b. Any ideas? (I'd still like to be able to differentiate and integrate t(x) in terms of x). -Alasdair _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Alasdair McAndrew 2013-05-14T10:52:29 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42291 <pre>Hi all: This must be serious! The discussion over Taylor Series lead me to believe that the series did not converge... it has been a hot topic for a straight 3 weeks now! Now where would I use Taylor Series in teaching physics that I would stumble upon the same problem? Makes me think if other software can do this right. Would Mathematica or Maple do it better? Thanks for insight in the discussions. Regards, Berns B. _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Berns Buenaobra 2013-05-14T07:57:55 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/42255 <pre>O n the Maxima ports page on Sourceforge&lt;http://maxima.sourceforge.net/ports.html&gt;, there is a list of ports to Windows, GNU, etc. where the most recent version of Maxima is between 5.9 and 5.16. What is the point of this page, when the Sourceforge download page&lt;http://sourceforge.net/projects/maxima/files/&gt;has version 5.30 on Mac and Linux, and 5.28 on Windows? For that matter, why is the Windows version (which according to Sourceforge is downloaded about 8x more often than Mac and Linux together) two versions behind Mac and Linux ? -s _______________________________________________ Maxima mailing list Maxima&lt; at &gt;math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima </pre> Stavros Macrakis 2013-05-11T19:22:29 Search the mailing list at Gmane query http://search.gmane.org/?group=$group=gmane.comp.mathematics.maxima.general