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/21054 How can I solve an inequality in Maxima? Radek 2008-05-17T18:08:42 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21048 I have the following maxima file ------ test.max ------------------- output_integer(z) := block( [tmp], tmp : file_output_append, file_output_append : true, stringout( "output.txt", "/* integer */" ), stringout( "output.txt", z ), file_output_append : tmp, return(z) ); output_integer(1); ------ test.max ------------------- using my NEW Maxima installation (maxima -b test.max), I have ------------------------------------------------ Maxima 5.15.0 http://maxima.sourceforge.net Using Lisp CLISP 2.45 (2008-05-15) 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) batch(test.max) batching /home/seirios/test.max (%i2) output_integer(z) := block([tmp], tmp : file_output_append, file_output_append : true, stringout("output.txt", "/* integer */"), stringout("output.txt", z), file_output_append : tmp, return(z)) (%o2) output_integer(z) := block([tmp], tmp : file_output_append, file_output_append : true, stringout("output.txt", "/* integer */"), stringout("output.txt", z), file_output_append : tmp, return(z)) (%i3) output_integer(1) Error in `stringout' attempt #0: output_integer(z=1)(test.max line 7) -- an error. To debug this try debugmode(true); ------------------------------------------------ whereas using my OLD Maxima installation (maxima -b test.max), I have ------------------------------------------------ Maxima 5.13.0 http://maxima.sourceforge.net Using Lisp CLISP 2.41 (2006-10-13) Distributed under the GNU Public License. See the file COPYING. Dedicated to the memory of William Schelter. This is a development version of Maxima. The function bug_report() provides bug reporting information. (%i1) batch(test.max) batching /home/seirios/test.max (%i2) output_integer(z) := block([tmp], tmp : file_output_append, file_output_append : true, stringout("output.txt", "/* integer */"), stringout("output.txt", z), file_output_append : tmp, return(z)) (%o2) output_integer(z) := block([tmp], tmp : file_output_append, file_output_append : true, stringout("output.txt", "/* integer */"), stringout("output.txt", z), file_output_append : tmp, return(z)) (%i3) output_integer(1) (%o3) 1 ------------------------------------------------ Andre andre maute 2008-05-17T15:19:48 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21044 _______________________________________________ Maxima mailing list Maxima< at >math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima ahmet alper parker 2008-05-17T13:52:39 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21042 Using Maxima 5.15.0, compiled on Debian Lenny AMD64 using CLISP. kill(all); (%o0) done (%i1) load (tex2ooo); (%o1) /usr/local/share/maxima/5.15.0/share/contrib/tex2ooo.lisp (%i2) 'integrate(x^2*exp(-%i), x); (%o2) %e^(-%i)*integrate(x^2,x) (%i3) tex(%); Maxima encountered a Lisp error: APPEND: A proper list must not end with " cdot " Automatically continuing. To reenable the Lisp debugger set *debugger-hook* to nil. (%i2) (s+1)/(s^4+3*s^3+4*s^2-2*s-3); (%o2) (s+1)/(s^4+3*s^3+4*s^2-2*s-3) (%i3) tex(%); Maxima encountered a Lisp error: APPEND: A proper list must not end with " cdot " Automatically continuing. To reenable the Lisp debugger set *debugger-hook* to nil. BTW: "cdot" is multiplication "." in OOoMath. Thanks Ismael Ismael Garrido 2008-05-17T03:53:09 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21038 I would really like it if wxMaxima had the 4 most recent files opened listed in the File menu (or a configurable number if not 4). That is all. Rich Richard Hennessy 2008-05-16T22:48:29 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21033 _______________________________________________ Maxima mailing list Maxima< at >math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima ahmet alper parker 2008-05-16T13:43:59 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21032 Dear All, Browsing through the Maxima manual a couple of weeks ago, I thought I saw a function for finding Taylor-series solutions to systems of non-linear ODEs. Only now I can't find it. Can anyone suggest search terms that might get me back to this, please? Dan Hatton 2008-05-16T11:38:38 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21029 Because I have only time in the evening hours and I use the time to look at the code, I can not answer so fast. I will open a bug report at the weekend. Perhaps further results I have got are interessting for you: 1. I have found a bug in the routine lt-exp and f35p147. This bug prevents the calculation of integrals with e.g. sin(2*sqrt(a*t)). SPECINT gives the result 0. Here the output of Maxima after correction: (%i6) radcan(specint(%e^(-s*t)*sin(2*sqrt(a*t)),t)); (%o6) sqrt(%pi)*sqrt(a)*%e^-(a/s)/s^(3/2) That is perfectly the tabulated expression and SPECINT now works for a lot of other integrals too. 2. To show how we can extend the algorithm of SPECINT to calculate further integrals, I have added code to calculate integrals of the form t^-1*(%e^(-a*t)-%e^(-b*t)). The code works also for integrals like t^-1*sin(a*t). Here an example (%i4) specint(%e^(-s*t)*t^-1*sin(a*t),t); (%o4) %i*(log(s-%i*a)-log(s+%i*a))/2 That's equivalent with the tabulated answer: atan(a/s) Dieter Kaiser Dieter Kaiser 2008-05-15T23:00:34 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21025 First of all i want to say hello, as i am new to this mailing list, and new to maxima. I have defined a (programming) function, which take a mathematical function as an argument, and should give me a new (mathematical) function: -8<------------------------------------- /* the error is defined as | df | | df | error(f(x,y, ...)) = | -- | * delta_x + | -- | * delta_y + ... | dx | | dy | and is a function of all arguments to f() plus all deltas of its arguments: df(x, y, ...., dx, dy, ...) */ error(fun, ret) := block( [ dep:dependencies, N:length(dependencies), vars:[], all_vars:[], dvars:[], num_vars, reservoir: [d1, d2, d3, d4, d5, d6, d7, d8, d9, d10] ], /* find out what arguments fun() takes via dependencies */ (for i:1 step 1 while i<=N doif (part(dep[i], 0) = fun) then (for j:1 thru length(dep[i]) do (vars: cons(part(dep[i], j), vars)))), vars: reverse(vars), num_vars:length(vars), /* define delta-parameter list */ (for i:1 thru num_vars do dvars: cons(reservoir[i], dvars)), dvars: reverse(dvars), /* argument list for the error function contains all of the arguments of the original function plus all the deltas of those arguments */ all_vars: append(vars, dvars), ret_f: funmake(ret, all_vars), temp_f: funmake(tempfunc, all_vars), fun_f: funmake(fun, vars), pt_f: funmake(pt, vars), /* initialize ret(...) */ define(''ret_f, 0), /* main stuff, construct error function */ (for i:1 thru num_vars do ( define(''pt_f, ''diff(''fun_f, vars[i])), define(''temp_f, ''ret_f), /* save current return function */ define(''ret_f, abs( ''pt_f)*dvars[i] + ''temp_f))), /* add the new partdiff */ ''ret_f); -8<------------------------------------ I hope, with the comments, you understand what i am trying to do. It is (at least for me :) ) not a simple task, as it should work with any function (of any argument count, with my "reservoir" it is limited to 10 args...). The behaviour of the code above is as follows (i have it in a file, partdiff.max): (%i1) batchload("partdiff.max"); (%o1) /home/pixelbrei/projects/maxima/partdiff.max /* first definition of the function */ (%i2) v(x):=x^2; 2 (%o2) v(x) := x (%i3) depends(v, x); (%o3) [v(x)] /* define a trivial example function, and inform maxima of the dependencies */ (%i4) error(v, dv); Improper function definition: ret_f #0: error(fun=v,ret=dv) -- an error. To debug this try debugmode(true); /* this is the error message it throws. */ (%i5) batchload("partdiff.max"); (%o5) /home/pixelbrei/projects/maxima/partdiff.max /* i define the function a second time */ (%i6) error(v, dv); (%o6) 2 d1 abs(x) /* now it works */ The second definition of the function only works, if i try to execute my "error" function between the two batchloads. As you see, i pass the name for the function i want to build as a second argument. So, can anyone explain why this code behaves like it does? And/or point me to some changes i can do to make it work the first time? Thanks in advance, Christoph Christoph Sarnowski 2008-05-15T20:12:53 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21024 _______________________________________________ Maxima mailing list Maxima< at >math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima Ronald Modesitt 2008-05-15T19:26:08 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21014 Hi All, I have a number of related questions that keep popping up, probably because I am still new to maxima and am missing something still. For example, how do convert a list to a sum, like from [a,b,c] to a+b+c? My thoughts and troubles on that so far: * apply(+,[a,b,c]) does not work because (unlike in lisp) + is an infix operator requiring exactly two arguments. * But I don't know of a reduce(+,[a,b,c]) that would do the trick as in lisp. Is there something like that available? * and I dont want to do something uggly like either lambda([l],sum(l[i],i,1,length(l)))([a,b,c]) or block(res:1, for e in [a,b,c] do res: res+e, res) Mainly because sometimes maxima doesn't seem to expand such a sum expression them. Can I force maxima to do that? * I would be happy to do it in lisp but then without having to bother about type conversions to much, and I don't know how to do that. Or is this not a good idea? Thanks, Joachim. Joachim De Beule 2008-05-15T15:05:53 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21010 I cannot obtain the 3d plotting of 2 functions (and more functions too): plot3d([7*x-3*y, x^2-y^2], [x,-5,5], [y,-5,5])$ List [7*x-3*y,x^2-y^2] is not of length 3 -- an error. To debug this try debugmode(true); Is this a bug? My student needed urgently this feature. Sorry if it is known issue. ___________________________________________ Krzysztof Le`sniak Krzysztof Leśniak 2008-05-15T11:11:41 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/21000 Dear Sir/Madam: I'm developing a book on Maxima. The first four chapters are available at this web site: http://www.neng.usu.edu/cee/faculty/gurro/Maxima.html Would it be possible to list the link in the Maxima Documentation page? Thanks, Gilberto Urroz Gilberto Urroz 2008-05-14T00:14:27 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/20999 _______________________________________________ Maxima mailing list Maxima< at >math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima Alexey Beshenov 2008-05-14T22:25:34 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/20996 Hello I was browsing the sources for the vect and vector packages. The vector package has a warning (from 1978, no less!) saying that it *might* be broken. The vect package states that it will soon be replaced (again, in another notice from 1978). What's going to happen to those packages? Which one is "current"? Both vect and vector are underdocumentated. The intent of those packages (AFAIK) is to implement the vector operators (grad, div, curl, laplacian). The documentation should be improved for these packages (or, for the package that should be used). How do I help improve it? Vector seems to handle the operators in multiple coordinate systems (coordsystem). Vect has a function that probably has something to do with that, but I cannot understand it (scalefactor). I want to work with the operators in, for example, cylindrical coordinates. Should I use vector, despite its warning? Should I use vect's scalefactor? How does it work? Thanks, Ismael Ismael Garrido 2008-05-14T18:17:46 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/20983 Hi all you Maxima experts, I need a cross product via a 3x3 anti-symmetric matrix. And I don't want to use load("vect") due to the commutative behaviour with the dot product. I want the following: A method/macro/whatever that takes a 3x1 vector [ ax ] [ ay ] [ az ] and creates the following anti-symmetric matrix out of it [ 0 - az ay ] [ az 0 - ax ] [ - ay ax 0 ] Just as a syntactical transformation, putting the vector elements into the right places inside the matrix (and adding a '-'). I want to use this method in that way (the numbers reflect the dimensions): resultmatrix33 : crossp33(matrix33 . vector31) . othermatrix33; It is important that it can transform the vector even if it is the result of a calculation like matrix33 . vector31 I don't know much about LISP so I might be thinking too much in C++ return value terms :-) Best regards, weaker weaker 2008-05-13T15:38:28 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/20975 Hi all, I was wondering how to define a second order function in maxima, i.e. a function returning a function. More concrete: I want to define a function make_fn(n) which should return a function fn(x), where the way in which fn(x) is computed depends on the initially provided n. I tried it as follows: make_fn(n) := lambda([x],n+x)$ fn3: make_fn(3) but this evaluates to lambda([x], x + n), whereas I want it to evaluate to lambda([x], x + 3) Thanks, Joachim. Joachim De Beule 2008-05-13T13:26:13 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/20974 Hello, group! What's the canonical way to resize a matrix? Here's my dirty solution: resize_matrix(m,rows,cols):=block([list: flatten(m), a], a[i,j]:= list[j+(i-1)*rows], genmatrix(a,rows,cols)); -- Andrei Zorine Andrei Zorine 2008-05-13T13:21:46 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/20971 _______________________________________________ Maxima mailing list Maxima< at >math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima Ronald Modesitt 2008-05-13T03:26:40 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/20970 _______________________________________________ Maxima mailing list Maxima< at >math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima Alasdair McAndrew 2008-05-13T00:53:19 http://comments.gmane.org/gmane.comp.mathematics.maxima.general/20957 I started to look at the code of the Maxima function $specint which calculate the Laplace transform. I have rearranged the code, drawn flow charts and added a lot of debug information to find the problems. To get an overview of the problems with the code I have taken the tabulated Laplace transforms from the website of EqWorld. There are 99 Examples tabulated. 47 examples pass the test. 53 examples don't give the tabulated answer. The file test_eqworld.mac includes comments to the examples which fails. Some answers of Maxima might be correct, but I can't show that the result is identical to the tabulated answer. I run this test file with the Maxima CVS-Version and GCL 2.6.8. I have divided the problems in the following cases: 1. Maxima has no algorithmen: In most cases Maxima gives an internal symbol like other-defint-to-follow-negtest or arbpow-failed. This is a known problem. In some cases we get a correct noun form of the unevaluated integral. At last there are many problems which gives a wrong answer. A lot of examples include terms like t^(-1) ... or t^(-1/2) ... Maxima can't calculate these integrals but we know solutions. A simple type of integral Maxima can't evaluate is the division by the sum of constants: (%i7) specint(%e^(-s*t)/(x+y),t); (%o7) other-defint-to-follow-negtest In this cases the exponential function is hidden in a summation. I have found a correction which works generally and gives the correct result: (%i7) specint(%e^(-s*t)/(x+y),t); (%o7) (1/(x+y)*s) 2. Maxima has an algorithmen for a special function but don't give the correct result: We get no results for functions like bessel_k, bessel_y, log, erf, erfc etc. For all these functions Laplace transforms are tabulated. Beside the test of EqWorld I tried to get results for the internal functions %l[n,a](x) - the Laguerre function - or %he[n](x) - the Hermite function. But I dont' get the expected result. Here the example for the Laguerre function: (%i6) kill(all); (%o0) done (%i1) assume(s>0,n>0),declare(n,integer); (%o1) [s > 0,n > 0] (%i2) specint(%e^(-2*t)*%l[n,0](t),t); Maxima encountered a Lisp error: Error in MACSYMA-TOP-LEVEL [or a callee]: $N is not of type NUMBER. Automatically continuing. To reenable the Lisp debugger set *debugger-hook* to nil. After correction of the code: (%i6) kill(all); (%o0) done (%i1) assume(s>0,n>0),declare(n,integer); (%o1) [s > 0,n > 0] (%i2) specint(%e^(-s*t)*%l[n,0](t),t); (%o2) (1-1/s)^n/s In the case of the Laguerre function I have found a bug in the transformation. After correction, Maxima gives the expected result for the Laguerre function. There may be further bugs. Or limitations of the algorithmen prevend the calculation of results. At least, these limitations should be documented for the user. 3. Maxima gets extra factors or terms in the result A simple example is the bessel_i function. Here we get an additional phase factor (v is the order of the Bessel function): %e^(%i*%pi*v/(-1)^(v/2) in all calculations. This factor vanishs when we introduce a small correction to the code. In other cases the problem seems to be more difficult. The testsuite shows that Maxima can evaluate a lot of different combinations of special functions. On the other hand it seems to me that Maxima fails on a lot of more simple examples. If it is interesting for the project I would like to investigate the problems further and present some corrections to the code. Dieter Kaiser _______________________________________________ Maxima mailing list Maxima< at >math.utexas.edu http://www.math.utexas.edu/mailman/listinfo/maxima Dieter Kaiser 2008-05-11T22:40:42 Search the mailing list at Gmane query http://search.gmane.org/?group=$group=gmane.comp.mathematics.maxima.general