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Jul
1
comment How to create a thick spiral then extract the coordinates from the image?
This caused me to experiment with drawing random spiral galaxies. Thanks for the diversion!
Jun
28
comment Building Pythonic Programming style to Mathematica with visually-accessible list comprehensions?
Lazy evaluation, probably not, but similar functionality can be attained with map. [f(x) for x in values] -> f /@ values
Jun
21
comment Efficient Sampling of A (Countable) Discrete Distribution
Unfortunately 100k terms doesn't even reach the 99th percentile which is where things really slow down. Heavy tails are a pain.
Jun
21
comment Efficient Sampling of A (Countable) Discrete Distribution
You can get a small speed up by premultiplying by A and removing that from the test in the loop. A significant speed up can be gained by compilation. However, the given distribution has a very heavy tail and so it is tricky to be fast for large quantiles without some adaptive sampling which is also tricky since the distribution involves Zeta functions that can't be compiled.
Jun
18
comment P-Values are inconsistent when using DistributionFitTest repeatedly
Under the null hypothesis the p-value has a uniform distribution on (0,1). So, you would expect 5% of the values to fall at or below 0.05 for example.
Jun
16
comment Is DistributionFitTest broken for some cases of TransformedDistribution targets?
The CDF is required for the chi square test in order to build bins. If CDF doesn't compute DFT will fail. As for why the CDF fails I'm not sure.
May
2
comment Second derivative of SmoothKernelDistribution PDF?
You might try KernelMixtureDistribution to avoid the piecewise linear limitation
Apr
19
comment Why do EstimatedDistribution and DistributionFitTest work this way
I recommend reading the following en.m.wikipedia.org/wiki/Lilliefors_test
Apr
19
comment Why do EstimatedDistribution and DistributionFitTest work this way
In one case the parameters are estimated internally. The null distribution for the tests assume the parameters are known apriori and so a correction to the p-value must be applied to account for the estimation. If you provide a fitted distribution the test assumes known parameters and makes no correction.
Mar
16
comment Generate a sample from a multivariate Cauchy distribution
Why not use MultivariateTDistribution with v = 1?
Feb
24
comment Creating Identification/Classification trees
mathematica.stackexchange.com/questions/19285/… may help
Feb
5
comment Is there a convenient way to sum TimeSeries objects in Mathematica?
You can also set the missing data method on the TimeSeries objects to None. Not sure if that will work, I don't have M in front of me to try it.
Feb
4
comment Is there a convenient way to sum TimeSeries objects in Mathematica?
TimeSeriesThread is what you want I think
Jan
17
comment What is the purpose of Internal`LocalizedBlock?
@Mr.Wizard just a little tidbit, if I recall correctly this was added for the purpose of fitted models being able to work with subscripted variables so I think Dan is right on here.
Jan
16
comment Why does TimeSeriesShift is just adding a fixed number of days?
That's probably why TimeSeriesShift does what it does. Both TimeSeries and TemporalData require unique time stamps. Also many algorithms are particular About uniform vs irregular spacing which is only preserved by a uniform shift.
Jan
15
comment Why does TimeSeriesShift is just adding a fixed number of days?
What should it do for January 29th?
Jan
14
comment Periodogram for irregularly spaced data
@Verbeia you should definitely file a suggestion with WRI for Periodogram to take TemporalData (and TimeSeries). This was on my todo list before I left I just didn't get to it.
Jan
9
comment Why is my data 10 times slower than random data when doing matrix multiplication
Computing the following Tally[ByteCount /@ Flatten[tb]] shows that some of your numbers have different byte counts due to large exponents. I doubt the data can be packed.
Jan
4
comment Rapid density estimation and rendering of decision regions
I'm glad to help.
Dec
25
comment Generate nonoverlapping random circles
Related mathematica.stackexchange.com/questions/2594/…