Mathematica

Select list elements and exchange them
Hi I have a problem. I have a list. testList={ {11,{2,3}},{21,{3,4}},{34,{5,6}},{51,{7,8}} } 1) From this list, select any element list such as {x,{3,4}}, where X is an arbitrary number. In general, position of {x,{3,4}} in "testList" is not fixed. 2) Select any element list such as {x,{3,4}} a... 20 May 2010 07:16

Random number generation( b/w two limits) with a
Hi In contrast to some of the answers you've already received, I thought you might be looking for random numbers that have a truncated Gaussian distribution. I'm taking your term "comply" to mean the distribution does conform to a Gaussian PDF (Probability Density Function), but only between given limits. I would ... 18 May 2010 02:44

Washington DC Area Mathematica SIG
Mathematica SIG (http://web.me.com/hrbishop.pmsi) MEETING 21 May 2010, 7:30 am Science Applications International Corporation (SAIC) 8301 Greensboro Drive McLean VA Southern Corner of Westpark Drive and Greensboro Drive Agenda 1. Prepared Talks Tick Tock, by Dan Martinez ABSTRACT. Using Mathem... 18 May 2010 02:44

Handbook of Mathematical functions
You might be interested in the online version of the Handbook of Mathematical functions from NIST. It is available at http://dlmf.nist.gov/. You can download a formula to Mathematica by Importing in LaTeX or MathML from the URL provided with a formula. For example: A generating function for the Chebyshev p... 19 May 2010 07:08

Multiple FindRoot
Find Lambda Values for Tan[Lambda] == -([Lambda]/h) and e.g. h = 0.5 the first 10 Lambda Values for h = 0.5 are In[27]:=Lambda = Out[27]= {1.837, 4.816, 7.917, 11.04, 14.17, 17.31, 20.44, 23.58, 26.72, 29.86} My solution requires 1) FindRoot for a wide range of starting (ending) values 2) Eliminate ... 19 May 2010 07:08

Overloading StringJoin
I use Join enough that I like to overload StringJoin to do it: Unprotect[StringJoin]; x_List <> y_List := x~Join~y Protect[StringJoin]; Then I can do this: {1, 2} <> {3, 4} {1, 2, 3, 4} Why doesn't Mathematica already do this? It seem like an obvious use of <>. Or is there a good reason that they don'... 21 May 2010 07:17

Remove points from InterpolatingFunction
Hello, I have an interpolating function with a small interval of low accuracy. Therefore I would like to remove all points in this interval. I already tried to overwrite the interval using Piecewise and Condition (/;). However a so defined function causes problems in my later calculations due to its higher compl... 21 May 2010 07:17

Need help evaluating cells in Kernel
I am having some difficulty evaluating a Table expression that finds cells in the current notebook with a given CellTag and evaluates those cells in the Kernel. Any help ? ... 16 May 2010 09:10

Questions about Word Wrap etc.
1. Why does it in effect need a blank like at the end of the text cell to wrap properly? 2. Why does it wrap when the rightmost text is many inches from the right edge? I basically never use it and wonder if I'm doing something wrong. (It wouldn't be the first time!) Also is there a way to default it to off... 17 May 2010 08:00

Code optimization
Suppose I have an expression like foo =(expression 1)/denominator + (expression 2)/denominator where "denominator" is itself a complex expression. Is it worthwhile for me to compute "denominator" once and use it explicitly in foo, or will Mathematica cleverly deduce that it needs to be computed only once? ... 17 May 2010 08:00