
Re: How does one get data out of a TemporalData object?
Posted:
Jun 19, 2013 1:22 AM


Does the following do what you want?
Plot[data["SliceData", t], {t, 0, 20}, Filling > Bottom]
The "SliceData" property performs the same interpolation as ListLinePlot in this case (can be controlled via Method option) and returns timevalue pairs.
Andy
On 6/17/2013 5:29 AM, Joe Gwinn wrote: > In article <kpjvbv$9mc$1@smc.vnet.net>, Andy Ross <andyr@wolfram.com> > wrote: > > Andy, > >> TemporalData has a number of properties for extracting the parts you >> need. To get the paths with time stamps use TemporalData[...]["Paths"]. >> To get the states use TemporalData[...]["States"]. >> >> I recommend looking at the details section of the documentation for >> TemporalData to see the full list of properties and read through the >> examples on that page to see how each is used. > I had looked over the documentation, and nothing jumped out. I looked > at every mention of TemporalData, and found nothing that seemed > suitable. > > But I didn't try States, so I just did. It yields a list of alternating > 1 and 2 values, which isn't a complete answer to the problem, as the > time values are missing. If one just uses Fourier[], one will get some > kind of Periodogram, which is not what is sought. > > Let me give a code example: > > \[ScriptCapitalP] = ContinuousMarkovProcess[{1, 0}, ({ > {3, 3}, > {1, 1} > })]; > data=RandomFunction[\[ScriptCapitalP],{0,20}] > Fourier[data] > > This yields a complaint: > Fourier::fftl: > (((((("\"Argument \!\(\*TagBox[\nRowBox[{\\\"TemporalData\\\", > \\\"[\\\", PanelBox[" 1) ", FrameMargins>Small], \\\"]\\\"}], > InterpretTemplate[TemporalData[Automatic, {{{1, 2, 1, 2, 1, 2, 1, 2, 1, > 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1}}, {{{0``15.954589770191005, > 0.01520207123587128013320057817736596917`14.129940038322594, > 0.95824522046395536932862513249273766604`15.644199356725549, > 1.53128564596308252148382664967984035205`15.736304825316484, > 2.28962713530000690099771260582537312886`15.797207858258304, > 3.28670141416927664988333023187555326092`15.839226787640209, > 3.38168097695521799981621844019305806672`15.842081650549387, > 4.0716904019295301685379386805431332727`15.859211783981653, > 5.25370702200219072713176547011226038622`15.878918089214274, > 5.91828379716574832280816964564910319058`15.88678718369098, > 6.12633788645240157414249230434964341735`15.888924305967711, > 6.19666658844600659408879868858704605186`15.889616516866917, > 9.58526332575202981025003709494096121015`15.911492152203763, > 9.8441361181069966832633195553354003832`15.912572420088354, > 14.33613695082054447978910756738149487066`15.925305933162454, > 14.96549983870748084202749476200455050281`15.926498477053611, > 15.17014786638371663403108748271496533041`15.92686559286194, > 15.36161929373388768828517022927544623659`15.927200484830422, > 15.67573549317739061376647722217804251544`15.927732699101226, > 15.8362986262877527919959498312816012794`15.927996832624787, > 16.94396941821241069345266065715083372759`15.929686408696478, > 17.04737697478590359190098510749722701209`15.929833245160726, > 22.73457835309395939446096043959096018021`15.93589515332067}}}, 1, {") > Discrete) ", 1}, {") Continuous) ", 1}, 1, {}}]& ], Editable>False, > SelectWithContents>True, Selectable>True]\) is not a nonempty list > or rectangular array of numeric quantities.\"") > > Now, note that the following appears to work: > > plot1 = ListLinePlot[data, InterpolationOrder > 0, > PlotRange > {1, 2.1}, Ticks > {Automatic, {1, 2, 3}}, > Filling > Bottom] > > But when I do this: > > datainter = > Interpolation[Normal[data] // First, InterpolationOrder > 0] > plot2 = Plot[datainter[t], {t, 0, 20}, PlotRange > All, > Filling > Bottom] > > I get a different answer, and other paths yield yet other answers. > > > What I'm looking for is for instance a function that can be called from > Table[] to yield a list of equispaced samples suitable for Fourier[]. > The locations and interval between samples may vary as needed to keep > Fourier happy  list length will be an exact power of two, and there > may be zero padding added. > > Thanks, > > Joe Gwinn > > >> Andy Ross >> Wolfram Research >> >> On 6/15/2013 3:25 AM, Joe Gwinn wrote: >>> I would like to generate some random signals for use in exploring >>> signalprocessing algorithms. >>> >>> For use as synthetic signals for the algorithm to chew upon, I'd like >>> to use ContinuousMarkovProcess and TelegraphProcess with >>> RandomFunction. With these, I can do statistics and plot things >>> freely. >>> >>> What I cannot quite get is a time series ready for such indignities as >>> Fourier[]. >>> >>> Now I can manually disassemble the data structure, but I don't find a >>> list of equispaced samples, I get a transition list, which is not the >>> same thing. >>> >>> Interpolation[Normal[temporal data object] // First, InterpolationOrder >>> > 0] almost works, but the fine details are smeared over, even though >>> InterpolationOrder > 0 works in ListLinePlot et al without apparent >>> smearing. >>> >>> What am I missing? It seems like Probability and Statistics has become >>> a walled city within Mathematica. I'm hoping to find a door in the wall, >>> rather than be forced to build by own little city one brick at a time. >>> >>> Joe Gwinn >>> >>

