Hi Marshall: Thank you for the example. I hadn't thought about using list_plot, and this is excellent. This is great support.
Regards, Steve On Tue, Feb 17, 2009 at 12:10 AM, Marshall Hampton <[email protected]>wrote: > > Here's a sort of hybrid solution, using odeint but then converting out > of the numpy types. > > T_steam = 250.0 > UA = 10.0 > M = 1000.0 > W = 100.0 > Cp = 2.0 > To = 20.0 > import numpy > from scipy.integrate import odeint > def dTdt(T,t): > dT1dt = (W*Cp*(To-T[0])+UA*(T_steam-T[0]))/(M*Cp) > dT2dt = (W*Cp*(T[0]-T[1])+UA*(T_steam-T[1]))/(M*Cp) > dT3dt = (W*Cp*(T[1]-T[2])+UA*(T_steam-T[2]))/(M*Cp) > return numpy.array([dT1dt, dT2dt, dT3dt], dtype=float) > t = numpy.arange(0r,200r,1r,dtype=float) > T_int = numpy.array([20.0r,20.0r,20.0r],dtype=float) > T = odeint(dTdt,T_int,t) > sdata = [[float(y) for y in x] for x in T.transpose()] > plots = [list_plot(x, plotjoined = True, rgbcolor = hue(sdata.index(x)/ > 3,1,1)) for x in sdata] > show(sum(plots), axes_labels=['t','Temperature'], ymax = 60) > > There is some work being done on improving support for plot legends > and better axes in Sage (by A. Bergeron and M. Hansen I believe); > right now sometimes its necessary to add text more directly with the > "text" command (produces a graphics object you can add to other > graphics). > > Hope that helps, > M. Hampton > > > On Feb 17, 12:25 am, Steve Yarbro <[email protected]> wrote: > > Hi Mike: > > > > Wow, thanks for the very timely response, that was warp speed. I've > tried > > your suggestion and I've stopped having the error message, but for some > > reason, I don't get a plot. I'm a newbie with Python coming from the > MATLAB > > world. I'll keep working with it, but here is what I have: > > > > t = arange(0r,200r,1r) > > T_int = array([20.0r,20.0r,20.0r]) > > > > T = odeint(dTdt,T_int,t) > > > > plot(t,T) > > xlabel('t') > > ylabel('Temperature') > > > > When I evaluate, I get the following: > > > > Text(0.5,0.5,'Temperature') > > > > Would a better approach be to use the ode_solver from Sage? > > > > On Mon, Feb 16, 2009 at 2:17 PM, Mike Hansen <[email protected]> wrote: > > > > > Hello, > > > > > This is due to the interaction between numpy/scipy and Sage's > > > datatypes. See my response at > > > > >http://groups.google.com/group/sage-devel/browse_thread/thread/7038a4. > .. > > > > > --Mike > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
