Mathematica

Unusually function for NDSolve.
I read an earlier thread titled 'How can I "perturbate" a NDSolve expresion?'. It came close to what I need to do. I didn't understand the nature of 'a' in NDSolve. Are there any references for this. I have a function that is part of the equations to solve, but when one variable crosses a threshold from below I n... 24 Feb 2010 07:30

adding graphics and calibration to plot3d
1) is there a way to add graphics to a 3d plot? which is the best? i use this piece of code to plot the module of a complex function. Plot3D[Log[ Abs[f[x + I y]]], {x, -2, 2}, {y, -2, 4}, ColorFunction ->Function[{x, y},Hue[N[Arg[f[x + y I]]/(2 Pi)]]], ColorFunctionScaling -> False] . i would like to add to t... 25 Feb 2010 02:35

detection of automatic range of plot?
when you plot an unlimited function, mathematica chooses the vertical range's limits. could i detect which are the limits chosen by mathematica to use them? thanks giuseppe ... 25 Feb 2010 18:13

WCSTools - Display astronomical FITS files with coordinate grid
Dear group, maybe this is interesting for some of you. I ported some of the functionality of the IDL astrolib library to Mathematica to enable the overlay of an celestial coordinate grid on top of an astronomical FITS image. I also used the new Documentation building capabilities of Workbench 2.0 to build some h... 24 Feb 2010 06:25

NDSolve error for partial DV
I try to numerically solve a set of 2 DV containing two functions depending on two variables x and t. x represents the position and t represents time. I have defined several boundary conditions ( for x) and one initial condition ( for t) However I receive an error from Mathematica so there is obviously some error... 25 Feb 2010 02:35

Must tell Compile that Clip returns a number.
(v7.0.1) I don't know whether this would be considered a bug or not, but it took me a bit to figure out what was going on, so someone else might find it useful. For some reason, Compile seems to expect Clip to return a list. (Maybe because it takes a list argument.) For example: In[1]:= Compile[{x}, Clip[x, {0... 25 Feb 2010 02:35

Transition to Wolfram Workbench
Hello, could you give some recommendations for a smooth transition to the workbench for packages developed in a standard mathematica notebook environment? Starting a completely new project in the workbench is one thing, but at least as important is the question how to continue to work on existing packages creat... 12 Mar 2010 08:18

NDSolve with Boundary Condition
Dear MathGroup members, Please help me with this: I am trying to solve an numerical equation: sol = NDSolve[{D[Y[z, t], z, z] + 10^12 Sin[Y[z, t]] Cos[Y[z, t]] == D[Y[z, t], t] with boundary conditions: d(Y[a, t])/dz = 2*10^6 and d(Y[b, t])/dz = 2*10^6 , but i don't know how to write the boundary condit... 25 Feb 2010 18:13

Exporting interactive 3D objects from Mathematica to PDF
Hi! Yes, there is. First you export your graphics to jvx. Then you convert this to u3d by using jReality [1]. This can be then incopoorated into pdf by the movie15-package. However, with jReality there are currently certain limitations on colors [2]. Yours Wolfgang --- [1] http://www3.math.tu-berlin.de/jreali... 23 Feb 2010 09:01

Digitizing plots with Mathematica (i.e. extracting data points
You should probably also consider the possibility that your image is not exactly horizontal/vertical. This will likely be the case if you scan an image from a book or journal. Kcvin Will DeBeest wrote: I've just written a blog post showing how to make a plot digitizer using Mathematica. It may be of int... 22 Feb 2010 19:48