Mathematica

Handle dynamic variables (any help appreciated)
Dear All, I am new to Mathematica and I am trying to handle a list which updates dynamically (at the end of this email you will find an example of the code). This gives me an error, since the list firstvar is actually NOT a list (I checked its length, and it gives me 1, instead of 6). If I assign := the value of... 25 Mar 2010 05:45

partial derivate of a function of vector variable
Hi, Let's say have function f of vector variable x. f[x_] := x[[1]]^2 + x[[2]]^2 How to compute partial derivate by x_1? Something like D[f[x], {{x[[1]]}}] does not work. I don't want to rewrite function f as f[x1_,x2_]. Thanks for help. ... 26 Mar 2010 06:53

Convert to lower Mathematica version
Hi all, A colleague has an older Version of Mathematica (4.1) and cannot open my notebooks. I run Mathematica Version 7. Is there a way to convert my Notebooks to make them compatible with the lower version? Thank you for your help! Dornakul ... 26 Mar 2010 06:53

How to pass additional parameters to the ticks function?
background: When plotting, one can supply a specific tick function, which is automatically called by the Plot code. This allows one to have control on how the ticks are set. This is useful. Here is an example: ------------------------------ ticksX[min_, max_] := Table[{i, Style[i, Red, 12], {0.04, 0}}, ... 26 Mar 2010 06:53

counting number of variables in an expression
Is there a straightforward way to count the number of variables in an expression? If it makes any difference what I'm looking at is the product of several polynomials in many variables with rational coefficients. ... 26 Mar 2010 06:53

estimation
Hi, Do you know how to estimate z (-1/2 exp(2*z)+3/2*exp(z)) where z is a complex number ( Re(z)<0). Thank You, Magdalena ... 25 Mar 2010 07:58

Mathematica front-end very sluggish under Linux
For a few months now I have been using Mathematica 7.0.1 under Ubuntu 9.10, and I'm finding the front end to be very sluggish. Scrolling is slow, and when I am editing a part of a large code block, it sometimes takes a few seconds for the characters displayed to catch up with my typing. Sometimes I am tempted to ... 8 Apr 2010 09:27

Calling kernel.dll from
At 02:46 AM 3/20/2010, =C0=EB=E5=EA=F1=E5=E9 =CF=EE=EF=EA=EE=E2 wrote: Todd , Many thanks for the detailed response. Both methods are shown by you, very interesting. And thanks for sending a separate copy of the message directly to me: message appeared in the newsgroup is damaged, and part of the code f... 24 Mar 2010 06:34

Probability Histogram Problems
I would like to have probability histograms that have the same minimum and maximum bin end points for easy comparison of histograms across multiple data sets. I want to be able to explicity control the end points of the histogram, even if there is no data in the minimum and maximum bins. For example, here is... 25 Mar 2010 05:45

Tube plot function in Mathematica???
Greetings, New to Mathematica. Can't seem to find a way to plot a line as a tube like this: http://facstaff.unca.edu/mcmcclur/java/LiveMathematica/trefoil.html Seems such an obvious function to have built in. Is there one? If not, can someone point me to one I can use in Mathematica? Thanks ... 24 Mar 2010 06:35