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visits member for 2 years, 7 months
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Aug
24
comment How to apply Gaussian kernel to smooth density of points on 2D (algorithmically)
I show a more low-level implementation in this answer, so you may want to read that and look up GaussianFilter
Aug
24
answered Customizing display of partial differential equations
Aug
24
comment Customizing display of partial differential equations
I can't resist pointing out that suppress is written with two p...
Aug
24
answered Table with dynamic iterator
Aug
24
reviewed Close How to find roots of a general 4th order polynomial equation
Aug
24
reviewed Close ToExpression from commandline
Aug
24
reviewed Close Trying to solve a trig identity
Aug
24
comment Under what conditions does Mathematica give a natural antiderivative when integrating?
@Anixx I don't think it's a bug in the 1/(x-1) case - it's a situation where the inverse Fourier transform involves a Cauchy principal-value integral (otherwise it's undefined). This seems to be a genuine counterexample to the thesis that all anti-derivatives of Fourier-transformable functions lead to the same unique choice of integration constants for both methods. I.e., the answer to your question is: there are no obvious general necessary and sufficient conditions that I would be able to formulate. But at least it works for many cases, including polynomials.
Aug
24
comment Can we teach Mathematica about functional differentiation?
@chris Sure, Mathematica probably can't do the limit in that case. But that's still better than getting a wrong result for that case, as you would with the accepted answer. Anyway, if you have an integral, are you sure you don't want the variational derivative instead of the functional derivative?
Aug
24
answered Higher order eigenvalue problem
Aug
24
comment Higher order eigenvalue problem
This becomes an eigenvalue problem for the unknown energy $E$ only when you specify the boundary conditions.
Aug
24
answered How to combine objects from different .obj files?
Aug
24
answered Under what conditions does Mathematica give a natural antiderivative when integrating?
Aug
23
comment What are the best tips in Michael Trott's beer/whiskey Wolfram Blog post?
Clearly the best tip: "Drive responsibly on brewery tours!" In terms of Mathematica, I'm afraid it's impossible to answer this.
Aug
22
comment Horizontally compress a picture with varying compression ratio
Do you mean that the part of the image from the left to the horizontal fraction x should be compressed, and that this compressed part of the image should replace the original part of the image? Or do you just want to get the left part of the image by itself? And by compression, you do you mean that you just want a quick display of that process or you actually want a new image with the result? The difference is that the display can be done without any image manipulations (image manipulations are quite slow in Mathematica).
Aug
22
comment On using DiracDelta[t] in OutputResposne in version 10. Different result from version 9
I see this issue too (version 10 on Mac OS X). The result is correct if I replace the delta function by 1000 HeavisideTheta[1/1000-t]. Seems like this would have to be called a bug...
Aug
21
answered Poincaré Section
Aug
21
comment ArrayPlot copied to PDF shows blurred mesh
I don't understand why you post this as a solution. Have you actually tried it? Then you must be seeing something in the FullForm of the PDF that I am not.
Aug
20
comment ArrayPlot copied to PDF shows blurred mesh
I tried CopyToClipboard and got a slightly better looking result in a Mac, I do still see very fine lines when magnifying in Preview... so I guess this is worth a bug report.
Aug
20
comment ArrayPlot copied to PDF shows blurred mesh
I also see this issue. Perhaps you can use one of the answers to this question instead: Plotting large datasets. A simple way to display the array is Image[1. - IdentityMatrix[4], ImageSize -> 360].