New answers tagged

3

DateHistogram was added in version 10.2, and uses date-specific bins and ticks. I'll use the same {month, day} data as my other example, but instead of transforming the dates ahead of time, I can use DateFunction to provide the interpretation automatically. blossom = {{4, 3}, {4, 22}, {4, 15}, {4, 2}, {4, 18}, {4, 20}, {4, 12}, {3, 30}, {4, 4}, {4, ...


0

Wolfram confirmed bug. Assigned to [CASE:3521328].


9

Another approach is to use compound median filtering which returns a blocky function. Then threshold the jumps between blocks. No assumptions about the number or size of blocks is made. Function to plot the input series as discrete jumps. BlockPlot[s_] := Partition[ Flatten[{s[[1]], Table[{{s[[i, 1]], s[[i - 1, 2]]}, s[[i]]}, {i, 2, ...


15

ListPlot@{l1, msf = MeanShiftFilter[l1, IntegerPart[Length@l1/10], MedianDeviation@l1, MaxIterations -> 10]} And here are the detected means (assuming there are three): fc = FindClusters[msf]; Mean /@ fc ( *{3.77282, 220.788, 387.444} *)


22

I had a go with HiddenMarkovProcess[], based on the assumption that the data is normally distributed around two different means (it looks like it!). This approach should be fine for cases where the number of "states" is small, e.g. 2 in this case. Otherwise you're looking at Infinite Hidden Markov Models, or see the bottom of this answer. To remove some ...


2

we can do a STFT of Sin[Pi*t^4] f[t_] := Sin[Pi*t^4]; data = Table[f[t], {t, 0, 5, 0.001}]; Spectrogram[data, SampleRate -> 1000] the instantaneous frequency of f[t] is $$\frac{\frac{\partial f(t)}{\partial t}}{2 \pi }$$.So the ideal instantaneous frequency is: Plot[Evaluate[D[Pi*t^4, t]/(2 Pi)], {t, 0, 5}] Ok,Combine the two image: Well ...


1

The literature on parameter estimation, or system identification, is vast, and there are many different approaches and techniques. Matlab has toolboxes that implement many algorithms, because many researchers in the field have adopted Matlab. For Mathematica, to the best of my knowledge, we don't have anything comparable. One would have to learn the ...



Top 50 recent answers are included