Re: why DateListPlot is so slow?
- To: mathgroup at smc.vnet.net
- Subject: [mg79964] Re: why DateListPlot is so slow?
- From: "Arkadiusz Majka" <arkadiusz.majka at gmail.com>
- Date: Thu, 9 Aug 2007 05:33:04 -0400 (EDT)
- References: <f9c0ae$5o4$1@smc.vnet.net> <46B99E1E.7060605@gmail.com>
Hmmm, Here you are DateListPlot[{{"00:00:08",153629},{"00:00:19",37200},{"00:00:30",48591},{"00:00:40",43455},{"00:00:50",38701},{"00:01:01",32449},{"00:01:11",48995},{"00:01:22",42385},{"00:01:33",38165},{"00:01:43",36008}}] (* and beautiful plot appears...*) Arek On 8/8/07, Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com> wrote: > > Arkadiusz.Majka at gmail.com wrote: > > Hi, > > > > I have a list (a time series): > > > > data={{00:00:30,x1},{00:01:00,x2},{00:01:30,x3},....} > > > > at equally spaced time intervals (30 seconds). The length od data is > > 8100 (24 h) > > > > DateListPlot[data] works fine but takes 28 sec, since > > ListPlot[data[[All,2]]] does it in less than 0.1 sec.... > > > > Can you explain me why DateListPlot is so time consuming? Can we > > improve it? > > As written, data is an invalid Mathematica expression: > > In[3]:= data = {{00 : 00 : 30, x1}, {00 : 01 : 00, x2}, {00 : 01 : 30, > x3}} > > During evaluation of In[3]:= Syntax::sntxf: "{" cannot be followed by \ > "00:00:30,x1}". > > During evaluation of In[3]:= Syntax::tsntxi: "00:00:30" is \ > incomplete; more input is needed. > > During evaluation of In[3]:= Syntax::sntxi: Incomplete expression; \ > more input is needed. > > Using strings does not solve the issue either > > In[1]:= data = {{"00:00:30", x1}, {"00:01:00", x2}, {"00:01:30", x3}} > > Out[1]= {{"00:00:30", x1}, {"00:01:00", x2}, {"00:01:30", x3}} > > In[2]:= DateListPlot[data] > > During evaluation of In[2]:= DateListPlot::ntdt: The first argument \ > to DateListPlot is not a list of pairs of dates and real values or a \ > list of lists of pairs of dates and real values. >> > > Out[2]= DateListPlot[{{"00:00:30", x1}, {"00:01:00", x2}, {"00:01:30", > x3}}] > > So the question is, "Could you please post an example of the _real_ > structure of the dataset you feed to *DateListPlot*?" > > -- > Jean-Marc >