Mathematica

WeatherData times
As one simple concrete example, when I put WeatherData["Buenos Aires", "Humidity", "DateValue"] I'm getting {{2010, 5, 10, 16, 0, 0}, 0.486} and it's still 14:15 pm of that day. $TimeZone gives -3 which is correct. I'm not sure if there's a timezone offset to all dates returned by Mathematica or what is happening... 11 May 2010 06:45

Unstructured Interpolation in V7?
I have a small data set (wind in the bay area, automatically extracted by Mathematica) testData={{{-121.082`,38.955`},{-0.017250000000004206`,0.02987787643056= 0946`}},{{-122.05`,37.98`},{0.03175000000000239`,0.054992613140314006`}},= {{-122.12`,37.66`},{0.06795173495784468`,-0.011981724259015891`}},{{-121.= 82... 12 May 2010 08:02

Discrete Fourier Transform
Hi guys I have a function f(x), and I need to find its discrete Fourier transform. I have taken a look at http://reference.wolfram.com/mathematica/tutorial/FourierTransforms.html, but it only returns the amplitude of the FT. - not the phase factor. Which command do I have to use in order to get the phase factor a... 12 May 2010 08:02

Number of ways of permutations to form a certain pattern of
On May 8, 7:07 pm, newlearner <poincare...(a)gmail.com> wrote: Dear all, How to compute in Mathematica the number of ways of permutations of n- objects to form a certain pattern of cycles? I mean, for example, let n = 3. then there are 6 ways of permutations of three objects 123, 231, 312, 132, 21... 10 May 2010 07:39

and a type of regular expression
On 5/9/10 at 7:51 AM, nycstern(a)gmail.com (Michael Stern) wrote: Is there an elegant way to do dictionary searches that match specified kinds of character repetition? For example, to search for six letter words that start with "d" and end with "k", where the third and fourth letter are the same? Finding si... 12 May 2010 08:02

help with DictionaryLookup[] and a type of regular
Hi Michael, I don't know how to do this using only regular expressions, but you can also use Mathematica's string-matching syntax. Here is one way: In[1]:= words = DictionaryLookup[{"English", "*"}]; In[2]:= Union@ Flatten(a)StringCases[ words, ("d" ~~ LetterCharacter ~~ (x : LetterCharacter) ~~ (y... 10 May 2010 07:39

help with DictionaryLookup[] and a type of regular expression
Is there an elegant way to do dictionary searches that match specified kinds of character repetition? For example, to search for six letter words that start with "d" and end with "k", where the third and fourth letter are the same? Finding six letter words that start with "d" and end with "k" is easy -- Dic... 11 May 2010 06:45

Mathematica in Education and Research?
I am looking for old issues of this discontinued journal. Are there any web archives or anything similar? All the links I found were broken. Thanks, S ... 9 May 2010 08:53

Heat exchanger network and Nminimize
I have some questions. How could I reduce computation time during working with Nminimize. I mean how to change tolerance or something like this. Is that possible to interrupt the calculation after 2 days in order to give some values? (in some optimization programs it is possible to have not very desired results by in... 8 May 2010 07:55

PlotLegend Bug?
Hi all, When I use PlotLegend in ParametricPlot, besides 4 plot legends I specified, 2more legend appeared. What's the problem? The code is as following: \[Psi]g[x_] := x; \[Psi]m[x_] := Piecewise[{{-x, x >= 0}, {0, x < 0}}]; \[Psi]p[x_] := Piecewise[{{0, x >= 0}, {-x, x < 0}}]; Needs["PlotLegends`"] Parame... 8 May 2010 07:55