Mathematica

A problem with derivative InterpolatingFunction from NDSolve
I get the following running Mathematica 7 on OS X 10.5.6 with 2GB alf= 1. 00 72703952 01 72686128 02 72691720 alf= 0.95 10 72563352 11 72549304 12 72548552 2008/12/23 dh <dh(a)metrohm.com>: Hi Olfa, I am running version 7 on Vista. That's the ouput I get: alf= 1... 24 Dec 2008 06:44

what am i doing wrong?
In[111]:= npv[cf0_, cf1_, cf2_, cf3_, cf4_, cf5_] := -(cf0) + cf1*(1/((1.12)^1)) + cf2*(1/((1.12)^2)) + cf3*(1/((1.12)^3)) + cf4*(1/((1.12)^4)) + cf5*(1/((1.12)^5)); (* Plan A NPV *) npv[3600000, 0, 0, 0, 0, 7000000] SetDelayed::write: Tag Real in 1304.33[cf0_,cf1_,cf2_,cf3_,cf4_,cf5_] is Protected.... 15 Dec 2008 08:28

"The requested evaluator is not currently defined"
I just tried to evaluate an expression in Mathematica 5.2 and got an error message "The requested evaluator is not currently defined." The problem likely arises from Mathematica 6.0.3 and Mathematica 7.0.0 both being installed (and they are working OK). But the preceding happens even with both of them closed ... 18 Dec 2008 07:47

Did I trash Mathematica installation?
In exploring ways to clear variables in all unprotected contexts, I executed this command: ClearAll["*`*"] I now realize that was a bad idea. System variables were affected also. I use Quit[] instead now. Did I trash my Mathematica installation? The help function does not seem to work as well. For example, th... 16 Dec 2008 03:18

Sample uniformly from a simplex
I've kept thinking about this and came up with the following. sampleSimplex[sampleSize_, dimensions_] := Module[{sample, sampleOutput}, sample = RandomReal[1, {sampleSize, dimensions}]; sampleOutput = Table[1 / Total[sample[[i, All]]] *sample[[i, All]], {i, 1, sampleSize}]; sampleOutput ... 23 Dec 2008 07:03

Manipulate question
Greetings I'm working on a Manipulate-based interface that takes user input from several drop down menus (in my application there are 9 of them) and then runs a set of calculations based upon the user's choices. By default Manipulate will run the calculation every time the user changes any of the drop down menus... 16 Dec 2008 03:18

Problem with MathLink using Mathematica 7.0
Until Mathematica 6.0.3 the following command used to work for me, and still does on the same machine (OS X 10.5.5, Intel): Install["Fluids/aeos", LinkMode -> Launch] Now with Mathematica 7.0 I get the error message: LinkOpen::linke : Could not find MathLink executable. The path is correct and the execut... 5 Dec 2008 06:34

InstallJava::fail
Hi, Each time I start Mathematica 6 and sometimes when displaying graphics, I get the error message "JLink`InstallJava::fail: A link to the Java runtime could not be established." But I have Java 6 update 10 installed. Any idea? Thanks, joerg ... 3 Dec 2008 05:51

Numerical General Relativity packages
Numerically solve the field equations? The field equations give different differential equations for different metrics. So, I guess you need a program that given a metric will give you the ODEs that govern the evolution of the metric components etc. Then you can use Mathematica's DSolve or NDsolve to solve these eq... 29 Nov 2008 05:23

Descarta2D (Exploring Analytic Geometry with Mathematica), Version 7
The Mathematica add-on package, Descarta2D, has been certified to be compatible with Mathematica Version 7 (previously certified for Versions 3-6). The entire textbook "Exploring Analytic Geometry with Mathematica" (including the user manual for Descarta2D) is available for free viewing and download at www.Descarta... 27 Nov 2008 06:23