On Fri, Jul 3, 2009 at 12:05 PM, guillaume ranquet <granq...@wyplay.com>wrote:
> Ryan May wrote: > > > > > > On Fri, Jul 3, 2009 at 8:32 AM, guillaume ranquet <granq...@wyplay.com > > <mailto:granq...@wyplay.com>> wrote: > > > > Hi list, > > > > I'm trying to get a dynamic plot running. > > I'm stuck at feeding the data to the lines. > > > > basically I've a callback that receives a (y,x1,x2) tuple and I would > > like to add the 2 points to the two matplotlib.lines of the figure. > > > > should I handle a copy of xdata/ydata and gives the updated set to > > set_x/ydata() for one point? > > I tried to get_data() and append to it, but It's a MaskedArray and I > > guess it means its a really bad idea to try this way. > > > > probably a new class inheriting figure and overriding > > get_data()//set_data() could do the trick? > > > > > > any advice on a _clean_ design I could use? > > > > > > You can add a value to an array using np.concatenate: > > > > x,y = line.get_data() > > x = np.concatenate((x, [x0])) > > y = np.concatenate((y, [y0])) > > line.set_data([x,y]) > > > > This is rather inefficient however if you're adding lots of points or if > > there are just a lot of point in x any in general. If you know how many > > points you're going to end up with, you could create mostly empty > > MaskedArrays and keep the extra points masked until you get the data. > > > > Ryan > > > > -- > > Ryan May > > Graduate Research Assistant > > School of Meteorology > > University of Oklahoma > > > thanks Ryan, > It does work and I'll use that for now. > the idea is to have a gkrellm-like UI in which you can monitor system > usage 'live' > I guess I could have a 'window of event', just keeping the last 1000 > points and move the xlim as a window: > ax.set_xlim(xmin=currentmin+time,xmax=currentmax+time) > but something sounds plain wrong, It sounds like there's too much > useless calculations and data copied. > > would it be a good idea to have an array of 1000 points and shift it > left every round to add the new point at the end? I think your best bet in this case is to just keep a python list of your 1000 points around: #Remove old point and add new one x_list.pop(0) x_list.append(x0) y_list.pop(0) y_list.append(y0) line.set_xdata(np.array(x_list)) line.set_ydata(np.array(y_list)) Ryan -- Ryan May Graduate Research Assistant School of Meteorology University of Oklahoma
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