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Nov
1
comment Inverse error function
From help for InverserErf it says Explicit numerical values are given only for real values of s between -1 and +1. But you have complex arguments.
Nov
1
comment Inverse error function
Can you show the Mathematica code? Because when I typed y = Exp[(Erf[I t]^(-1))^2]; Plot[y, {t, -1, 1}] I get this !Mathematica graphics
Nov
1
comment symbolic integration of product of hankel function and trignometric function
There is no closed form solution for Integrate[BesselJ[0, k r] Cos[r], r] which what causes this to fail. There is a analytical solution for k=1. k = 1; Integrate[r*Cos[r]*HankelH2[0, k*r], r] gives 1/4 (2 r^2 HypergeometricPFQ[{1/4, 3/4}, {1/2, 1/2, 2}, -r^2]- I Sqrt[2] MeijerG[{{1, 5/4, 7/4}, {1/2}}, {{1, 1}, {0, 1/2, 3/2, 3/2}}, r, 1/2]) might also be better to ask this on the math group.
Nov
1
comment Manipulate causing frequent crashes
Which version and which platform?
Oct
31
comment Expand just first level of an expression
minimal input and expected out?
Oct
31
comment Why does the documentation call functions “pure”?
Mathematica pure functions really should be called anonymous functions. en.wikipedia.org/wiki/Anonymous_function Java now has them, called there as lambda functions. C++ 11 has them also. The name "pure" is overloaded a little. The main thing is "is a function definition that is not bound to an identifier" from the above Wiki
Oct
31
comment Curve fitting of a list
Try polynomial fit. For n degrees of freedom, you need n-1 order polynomial for exact fit, if this is what you are asking. So if you have 10 points, try 9th degree poly. Not a good way to do fitting due to high oscillation, but if that is what you want. You tell M what the function to you want to fit to, and M will do it. Spline fitting is supposed to be the best, but I am no expert on data fitting.
Oct
31
revised Put/Get don't accept a string-valued expression as filename
added 277 characters in body
Oct
31
comment Put/Get don't accept a string-valued expression as filename
@lurscher make sure your notebook is in same directory where you save the file? It works for me !Mathematica graphics just do SetDirectory[NotebookDirectory[]] before exporting.
Oct
31
answered Put/Get don't accept a string-valued expression as filename
Oct
31
comment Curve fitting of a list
Have you tried reference.wolfram.com/language/ref/Fit.html and reference.wolfram.com/language/ref/FindFit.html ?
Oct
30
answered Non linear model fit
Oct
27
awarded  Good Question
Oct
26
comment Could I define 0^0 to be 1?
I used before Leonid solution f = Unevaluated[#1^#2] /. HoldPattern[0^0] :> 1 & how-to-tell-mathematica-to-replace-0-to-power-0-by-1
Oct
26
comment An efficient way to compare two matrices
can't you take just the norm of the difference of the 2 matrices? There are number of norms defined for matrices. reference.wolfram.com/language/ref/Norm.html may be pick the appropriate norm for your needs, as in Norm[mat1-mat2, "Frobenius"] ? This will work for sparse matrices as well.
Oct
26
comment How to build a constant Graphics object
If you can show the plot1, may be someone can suggest some things. For example, adding Opacity can slow down things quite a bit (since this requires more layers), I remember there was another graphic primitive that was expensive to use but forget it now. You can btw test this yourself. Make a manipulate that only displays plot1, like this Manipulate[x;plot1,{{x,0,"x="},0,1,.1}] and let it run (play the slider). You can now get an idea how long it takes to render plot1 on its own each time. You'll see that the less 3D points/primitive, the faster it will run.
Oct
26
comment How to build a constant Graphics object
since plot1 is constant already (it is evaluated before even Manipulate does anything), then M does not evaluate it again. What you are seeing in the rendering of it on the screen, which is slow for large objects, not the evaluation. You can try to Rasterize plot1 and see if this improves the rendering performance.
Oct
26
answered Unexpected Integration Constant
Oct
25
comment Distance Time Warp (DTW) function implementation in mathematica
There is some here forums.wolfram.com/mathgroup/archive/2003/Jul/msg00544.html
Oct
25
answered Assigning to the “local” version of a symbol