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location Sydney, Australia
age 48
visits member for 2 years, 2 months
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Jun
22
comment LiftingWaveletTransform with irregular grids
Thanks @eldo, but b is just a {8,8} array and, therefore, representing a signal/function in a regular grid of $(i/8,j/8)$ points, that is not irregular.
Jun
10
comment Calculate support of given wavelet
Thanks a lot @Sektor. Your comment about the "impulse response" got me thinking and I was able to arrive to something similar to yours using the "PrimalHighpass" coefficients (it is most likely the same, but I will double check with yours; fantastic.)
Jun
10
comment Calculate support of given wavelet
Thanks a lot @Sektor, but the support of second graph (wavelet) seems to be around [-6,4], isn't it? This is what confuses me, because the values for $x$ where $\psi _{j,k}(x)$ is guaranteed to be zero don't seem be just outside of [0,$2^{-j}$].
Jun
10
comment Calculate support of given wavelet
I want to use DaubechiesWavelet.
Mar
20
comment How to keep labels inside the box in BarChart3D
It does! @Kuba, you should post it as answer; happy to accept it. PlotRangePadding -> .35 is just perfect :)
Mar
20
comment How to keep labels inside the box in BarChart3D
@Kuba, thanks for asking. BarChart3D rotate the labels as you change the point of view. The 3D position and overall size seem ok for very short labels as shown in first picture, but for longer labels it seems there is not enough room to display and they overflow the bottom plane. It is a little bit pedantic on my side, I am afraid, but if there is an option to change some position or size I am willing to spend some time perfecting the drawing ;-)
Feb
16
comment Why does Mathematica evaluate Sin[2.0] but not Sin[2]?
Funnily enough, @DonComo, this N[Sin[2], 2]^2 + N[Cos[2], 2]^2 == 1 is True, although you may get a very different result in traditional programming languages. Here is what you get in Ruby (irb): ` Math.sin(2).round(2)**2 + Math.cos(2).round(2)**2 == 1` => false. The reason is that Mathematica keeps track of precision and, at the level of precision requested, the two expressions are the same :)
Feb
16
comment Measuring fractal dimension of natural objects from digital images
@VitaliyKaurov, glad you liked it. Note that Viola & Jones rightly pointed out a link between integral image and Haar wavelet basis in their paper; although this wasn't explored further. It is unclear to me the link between the paper you mentioned and fractal dimension, but certainly worth reading as I am interested in these kind of problems. Cheers.
Feb
1
comment Better way to get Fisher Exact?
Unexpected but interesting answer. Acknowledged as promised!
Jan
31
comment Better way to get Fisher Exact?
Thanks a lot @romke-bontekoe. This is for someone who expects/needs p-values as practiced usually in medicine research, i.e. from a frequentist point of view. Do you know any support of this Bayesian view in medicine/genetics? Interestingly enough, your examples are suitable for Pearson's $\chi^2$, although the test in this context is whether one has an expected matrix having the same row and column sums as the data or not. In a Bayesian view, prior knowledge of both, row and column sums, right? Again, thanks, very interesting!
Jan
30
comment BarChart3D does not print zeros and odd tick positions
@Murta, I haven't received an email to upgrade, I have 9.0.0.0 on Mac. Maybe I should contact Wolfram.
Jan
30
comment BarChart3D does not print zeros and odd tick positions
Thanks @Mr.Wizard, I have version 9.0.0.0 and it seems behaviour changed. I am happy with my workaround tough. If you can shed light on how to place the labels I will give you the answer; my current manual placing is not portable to other NxM matrices, which is bad. Cheers!
Jan
25
comment Is it possible to embed a cdf file into a GitHub Page
In addition to the embedding code, one usually needs to ensure the webserver sends the right MIME type. And afaik, github does not allow this, see
Jan
19
comment Data acquisition from a Measurement Computing USB device
Have you seen the device interface? And this guide?
Jan
16
comment Pattern matching
Good! Note that as said in the guide "/" is also not a built-in. You may also want to explore commutativity and associativity, Orderless and Flat properties in Mathematica terms; and OneIdentity, which is Mathematica 's way to say that Plus[x] is just x, kind of saying that Plus has an identity element without mentioning it. See here
Jan
16
comment Pattern matching
Oh @rm-rf, just noticed your comment after posting answer; again...
Jan
15
comment Signal processing by means of WaveletTransform
@Ivan, there are good answers already; just let me add that from an engineering perspective you have to consider other aspects of your problem: the limitations of your device (inside the "real industrial object"?); is this an ongoing issue or a single instance...? And the socio-engineering aspects: who is going to maintain that code, what sort of environment? Do you need to implement it in hardware or software? You certainly can run Mathematica in a RaspberryPi, which is good news; but it all depends on the context of this problem.
Jan
14
comment Fitting data using a differential equation
@thils, I am not sure about your problem space. I added few ideas you can use. Good luck!
Jan
13
comment Fitting data using a differential equation
@thils, I noticed that the solution from NDSolve was differentiable already; hence my answer :)
Jan
10
comment Draw only part of axis in graph
Yes, not easy as a general problem - approachable for a particular case. It depends on how much effort you want to put in your graphic, I believe. OTOH, I haven't checked CustomTicks; if someone has a free solution that fits the bill, go for it :)