Mathematica

Surprising behaviour with nested pure functions and local parameter
Hello everyone :-) This topic is about nested pure functions and the local parameters that they use. I'll start by quoting the Mathematica Book version 5, page 385: "Mathematica uses a uniform scheme to make sure that the names of formal parameters which appear in constructs like pure functions and rules ar... 9 Apr 2010 04:31

Plot and advanced filling
Hi, I have a plot with two curves in it. Let's make things simple and say the first one is x[t]:=t and the second one y[t]:=-t+1. Plotting shall be done on the interval [0,1]. So far so good. Now I want to fill in the area in which t < x[t] and t < y[t]. If I use Filling->Axis, of course the area below the whol... 10 Apr 2010 06:56

Using numbers close to to zero in Mathematica version 6
What does Mathematica version 6 give when the following is evaluated? Here (x) is 'zero' with 80 digits of accuracy. x = SetAccuracy[0, 80]; { Abs[x] < 10^-900, Positive[x], Negative[x], NonPositive[x], NonNegative[x] }//InputForm {Sign[x], SetPrecision[x, 20], Sign[0], KroneckerDelta[x] } UnitStep[{0... 10 Apr 2010 06:56

evaluate the floor s to yield a number
In[82]:= J = 367*y + floor (7*(y + floor ((m + 9)/12))/4) + int (275*m/9) + da + 1721013.5 Out[82]= 2.44254*10^6 + 7/4 floor (1966 + (17 floor)/12) + (2200 int)/ 9 How do you evaluate the floor s in the output in this example to yield a number for the Julian Date. ... 10 Apr 2010 06:56

there is an "oops" with Root and Limit
Dear group, please have a look at the following! In[1]:= $Version Out[1]= 7.0 for Linux x86 (64-bit) (February 18, 2009) In[2]:= f[t_] = Root[1 + t*#1 + #1^6 & , 2]; In[3]:= Plot[f[Exp[t]], {t, Log[6/5^(5/6)], 10}, FrameTicks -> {Transpose[{Range[10], Exp[Range[10]]}], None, None, -(Range[0, 15]/20.)... 9 Apr 2010 04:31

How to enter an integral in a formula and have
Hi Jim, If you are only interested in numerical values, then the best probably is to explicitly specify that your function <f> expects a numerical input: Clear[f]; f[x_?NumericQ] := NIntegrate[g[y, x], {y, 0, 1}] If you simply want to delay evaluation until the function <f> is called, this is achieved si... 9 Apr 2010 04:31

List Manipulation: Conditionally changing y value when x value meets some criteria
Hello, If possible I could use a little help on this. I have a list of x and y data and based on the value of x I would like to manipulate the value y. I joined the data using: pts=MapThread[{##1}&,{x,y}] I assumed that by testing the x value using #[[1]], I could change the value of y usin... 10 Apr 2010 06:56

Automatic method in Eigenvalues
Hi, With Mathematica it is easy to obtain the Eigenvalues of a (large) matrix (Function Eigenvalues). Currently I am writing a paper and I would like to know which algorithm is used by Mathematica for a n x n matrix (n >= 5). The eigenvalues cannot be determined analytical, thus I am interested in which numerica... 9 Apr 2010 04:31

Mathematica Cluster Integration + SGE
i am getting this error when Mathematica checks for SGE initialization. (its running on MAC OS Leopard 10.5.6) Java::excptn: A Java exception occurred: java.lang.UnsatisfiedLinkError: no drmaa in java.library.path at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1753) at java.lang.Runtime.loadLi... 8 Apr 2010 08:21

How to enter an integral in a formula and have mathematica *not*
I have a certain integral, part of a larger expression, that can be expressed in terms of incomplete gamma functions by Mathematica. But in carrying out the definite integral and forcing it to be written in terms of gamma functions, this introduces branch points and other unnecessary complications. I want the int... 10 Apr 2010 06:56