[sage-support] phase portrait with sage.
I trying to make phase portrait with sage (without using maple) with plot_vector_field function, but all my tryings fail. My system looks like: x''+x=f(x) , where f(x)= a, when xb x*a/b, when -b=x=b -a, when x-b a,b - predefined constants (positive) how I must do this? -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: sage server
Hi Jason- Sorry to keep bugging you about this but I think I'm getting closer to getting this working. I have found a bunch of apache mod_rewrites has taken care of many problems, but I the the ajax calls are still broken. I have identified a javascript function called asych_request which appears to be a prime candidate for a base-url prefix. My problem now is that the javascript code appears to be compressed or shrouded in the deployed sage math version. Is there a command or section of the makefile that rebuilds the deployed javascript code (in /javascript) from the readable code found in the devel directory? I am thinking that I could add a base url to this function, rebuild it, and see if that moves this along. Thanks, Tom On Mar 18, 5:03 pm, Jason Grout jason-s...@creativetrax.com wrote: On 3/18/11 6:22 PM, tbensky wrote: Thanks Jason---I found a todo.txt in the sagebn directory referencing some need for base_url. Is this what you are referring to? Some base_url on the html pages? When I inspect my Apache Proxy logs, Javascript calls to things like trash_notebook are routed to my /var/ www/trash_notebook directory, as are things like /var/www/eval, etc. These obviously need to be rerouted, but I am looking to dive into the core sage javascript code? This would be painful. That todo note was what I was thinking about. Unfortunately, after reading a bit more, it seems that the html base tag only works for relative URLs on a page, but there are plenty of javascript and css things that are absolute references. So I don't know how much it would do, and it looks like a much bigger (but still doable!) job to go through each URL and replace it with either a relative URL or a URL that uses some option from the notebook command to change the base directory. Jason -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: Problem in displaying graphs
With some fiddling,
\sageplot{Graph(d).plot(), axes_pad=0.1)
works around the problem.
On Mar 19, 6:50 pm, pong wypon...@gmail.com wrote:
Sage plots some graphs with vertices partially chopped off.
For example:
sage: d={1:[2,3,5], 2:[3], 3:[4,5], 4:[5]}
sage: Graph(d).plot()
I thought the bug was fixed, but looks like it still exists.
There is a work around using something like G.show(axes_pad=0.1).
However, I couldn't make it works with sagetex because axes_pad seems
to have no effect on G.plot().
Any help?
Thanks in advance
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[sage-support] Re: phase portrait with sage.
import scipy.integrate
import matplotlib.pyplot as plt
import numpy
a=1.0
b=2.0
def fun(t):
if t=-b:
return -a
elif fb:
return t*a/b
else:
return a
g=lambda t:fun(t)
N=100
time_step=0.1
time_end=10.0
t0=0.0
x0=[[0.5*k,0.5*k] for k in range(-10,10)]
def f(x,t):
return [x[1],-x[0]+g(x[0])]
time_range=[t0..time_end, step=time_step]
plt.figure()
for n in range(10):
sol = scipy.integrate.odeint(f,x0[n],time_range)
x = sol[:,0]
y = sol[:,1]
plt.plot(x,y)
plt.savefig('phase.png')
#corresponding vector field
x0,x1=var('x0 x1')
p=plot_vector_field ((x1,-x0+g(x0)),(x0,-8,8),(x1,-8,8))
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[sage-support] Re: phase portrait with sage.
Slightly more Sage-ified version of the above very nice solution:
import scipy.integrate
a=1.0
b=2.0
def fun(t):
if t=-b:
return -a
elif fb:
return t*a/b
else:
return a
g=lambda t:fun(t)
N=100
time_step=0.1
time_end=10.0
t0=0.0
x0=[[0.5*k,0.5*k] for k in range(-10,10)]
def f(x,t):
return [x[1],-x[0]+g(x[0])]
time_range=[t0..time_end, step=time_step]
x0=[[0.5*k,0.5*k] for k in range(-10,10)]
sol_lines = Graphics()
for n in range(10):
sol = scipy.integrate.odeint(f,x0[n],time_range)
sol_lines += line(sol,rgbcolor=hue(.3+n/15.0))
x0,x1=var('x0 x1')
p=plot_vector_field ((x1,-x0+g(x0)),(x0,-9,9),(x1,-7,7))
show(sol_lines + p, figsize = [9,7])
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