Mathematica

Plot3d causes crash with radeon driver and
On Thu, 2009-12-03 at 06:14 -0500, Nils Kanning wrote: The crash seems to be related to http://bugs.freedesktop.org/show_bug.cgi?id=22851 and there is also a fix for this bug. So hopefully with the next Mesa release this fix also arrives in Debian, Ubuntu and so forth. Nils Now the new Mesa versi... 7 Jan 2010 02:29

Storing lists on SQL
Hi. I'm trying to store lists on an SQL database. The lists can contain strings, rules, lists and integers etc. I plan to store them in a variable character field as a single string, but the first problem is the quotes on the inner strings have to be elided, e.g./" At the moment I'm trying a recursive routine wi... 8 Jan 2010 07:10

RSolve problem: won't solve convolution recurrence relation.
I am using mathematica 7, and am trying to solve a recurrence relation using the code below: RSolve[{f[x] == Sum[f[i]*f[x - i], {i, 1, x - 1}], f[1] == 1}, f[x], x] but it gives me the RSolve::piarg error. I have found that the solution for the above problem is in fact f[x_] = Product[(4*i - 6)/i, {i, 2, x}... 6 Jan 2010 08:42

JLink error
I created a jar file that runs methods that I have created in Mathematica. The java file has everything(libraries, import) it needs to connect to the Mathematica Kernel and run the methods. My issue is that I am using my jar file in Ruby. I have imported the jlink library, my jar file, and everything else I fee... 6 Jan 2010 08:42

NDSolve problem with switching
Here are simpler choices for the box wave. box[x_] = Piecewise@{{1, FractionalPart@x < .5}} Plot[box@t, {t, 0, 2}] or box = If[FractionalPart@# < .5, 1, 0] &; But, strangely enough, they don't speed things up in NDSolve. Clear[y1, y2] eqns = {y1'[t] == y2[t], y2'[t] == 1000 (1 - y1[t]^2) (y2[t] - ... 6 Jan 2010 08:42

mathproject10
15 notebooks on number theory free download at: http://www.simtel.net/free/Math-related-Programs/mathproject10/398496.html ito buda -- questo articolo e` stato inviato via web dal servizio gratuito http://www.newsland.it/news segnala gli abusi ad abuse(a)newsland.it ... 6 Jan 2010 08:42

inequality as constraints on NDSolve
Dear Mathematica experts: is there a possibility to implement a constraint in NDSolve? Suppose I want to solve NDSolve[{x'[t] == -y[t] - x[t]^2, y'[t] == 2 x[t] - y[t]^3, x[0] == y[0] == 1}, {x, y}, {t, 20}] But I want that the solutions satisfied the inequality x[t]>0 for every t (because it ... 14 Jan 2010 06:50

Wrong ODE solution in Mathematica 7?
Hi! I tried solve the ODE: DSolve[D[y[x], x, x] == -Cos[x]/(1 + Sin[x])^2, y[x], x] The solution what M7 (and Wolfram Alpha) gives is: y[x] -> C[1] + x C[2] + (2 Sin[x/2])/(Cos[x/2] + Sin[x/2]) I think, it's wrong! (Does anybody know how to check?) Another system gives for the same diff.eq: y(x) = -2/(tan((1... 6 Jan 2010 08:42

NDSolve problem with switching equations
Hello, everyone. I am trying to solve a switching ND problem using NDSolve. Specifically, suppose the system equation is y1'[t]==y2; y2'[t]==1000(1-y1^2)y2-y1; y1(0)==0;y2(0)==1; Then every half a second (0.5s), the system equation transforms to y1'[t]==y2; y2'[t]==1000(1+y1^2)y2; and then, after ... 6 Jan 2010 08:42

Difficulty with NDSolve (and DSolve)
Hi, I am trying to numerically solve a differential equation. However, I am encountering difficulty with Mathematica in generating valid numerical solutions even for a special case of that equation. The differential equation for the special case is: F'[x] == - (2-F[x])^2/(1-2 x + x F[x]) and F[1]==1. These e... 3 Jan 2010 04:04