Hello. I believe the issue is that earlier in the tutorial I had set sage: RealNumber=float
but I didn't specify to reenter this in the section you were looking at. If you enter this before the example it will work fine. The issue is that as William indicated, if you do not do this, instead of numpy floats in x, you get sage reals which are not as fast and don't work with numpy. I will look over the tutorial, but there may be some more instances where I forgot to re-specify that this needed to be entered. You may also wish to note that I have a slightly newer version of the notes here on my webpage http://www.math.washington.edu/~jkantor/Numerical_Sage/Numerical_Sage.html which is a bit ahead of the one in sage documentation (I need to update it). Josh On Aug 31, 1:50 pm, William <[EMAIL PROTECTED]> wrote: > Hi, > > This is an issue with the preparser and numpy not playing well > together. E.g., if you do this it works fine: > > sage: preparser(False) > sage: import numpy > sage: j=numpy.complex(0,1) > sage: num_points=50 > sage: u=numpy.zeros((num_points,num_points),dtype=float) > sage: pi_c=float(pi) > sage: x=numpy.r_[0.0:pi_c:num_points*j] > sage: u[0,:]=numpy.sin(x) > > Note that the command "preparser(False)" isn't supported in the > notebook yet. You %python or > switch to python mode. > > In the long run we hope to improve numpy / SAGE interaction. > > On Aug 30, 1:03 am, legout <[EMAIL PROTECTED]> wrote: > > > Hi, > > > i´ve got the following problem on my sage installation. > > The folloing code > > fromhttp://www.math.washington.edu/~jkantor/Numerical_Sage/node11.html > > Didn´t work for me: > > > import numpy > > j=numpy.complex(0,1) > > num_points=50 > > u=numpy.zeros((num_points,num_points),dtype=float) > > pi_c=float(pi) > > x=numpy.r_[0.0:pi_c:num_points*j] > > u[0,:]=numpy.sin(x) > > --------------------------------------------------------------------------- > > <type 'exceptions.AttributeError'> Traceback (most recent call > > last) > > > /home/volker/<ipython console> in <module>() > > > <type 'exceptions.AttributeError'>: 'float' object has no attribute > > 'sin' > > > I can use this (its the same, because sin(x[-1])=0) > > > u[0, :-1]=numpy.sin(x[ :-1]) > > > And using real instead of float, and everything works as aspected > > > pi_c = real(pi) > > x=numpy.r_[0.0:pi_c:num_points*j] > > u[0,:]=numpy.sin(x) > > > Is this a bug in sage? On my normal python + numpy session the first > > code runs just find. > > > volker --~--~---------~--~----~------------~-------~--~----~ 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://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
