Hello.
How do I define a piecewise function that are discontinuous in one point?
I mean, how do I define a piecewise function f(x) if it is like
x if 0<x<1
f(x)=2 if x=1
2-x if 1<x<2
If I try the command below:
sage: f= Piecewise([ [(0,1), x], [(1,1), 2], [(1,2), 2-x] ])
There's no error, however if I try to calculate f(1), I get:
sage: f(1)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
/home/bacani/<ipython console> in <module>()
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/functions/piecewise.pyc
in __call__(self, x0)
638 for i in range(1,n):
639 if x0 == endpts[i]:
--> 640 return (self.functions()[i-1](x0) +
self.functions()[i](x0))/2
641 if x0 == endpts[0]:
642 return self.functions()[0](x0)
TypeError: 'sage.rings.integer.Integer' object is not callable
And if I try to plot the function, I get:
---------------------------------------------------------------------------
ZeroDivisionError Traceback (most recent call last)
/home/bacani/<ipython console> in <module>()
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/misc/decorators.pyc
in wrapper(*args, **kwds)
571 kwds[new_name] = kwds[old_name]
572 del kwds[old_name]
--> 573 return func(*args, **kwds)
574
575 return wrapper
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/misc/decorators.pyc
in wrapper(*args, **kwds)
430 options['__original_opts'] = kwds
431 options.update(kwds)
--> 432 return func(*args, **options)
433
434
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/plot/plot.pyc
in plot(funcs, *args, **kwds)
3024
3025 if hasattr(funcs, 'plot'):
-> 3026 G = funcs.plot(*args, **original_opts)
3027 # if we are using the generic plotting method
3028 else:
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/functions/piecewise.pyc
in plot(self, *args, **kwds)
1000 """
1001 from sage.plot.all import plot
-> 1002 return sum([plot(f, a, b, *args, **kwds) for (a,b),f in
self.list()])
1003
1004 def fourier_series_cosine_coefficient(self,n,L):
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/misc/decorators.pyc
in wrapper(*args, **kwds)
571 kwds[new_name] = kwds[old_name]
572 del kwds[old_name]
--> 573 return func(*args, **kwds)
574
575 return wrapper
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/misc/decorators.pyc
in wrapper(*args, **kwds)
430 options['__original_opts'] = kwds
431 options.update(kwds)
--> 432 return func(*args, **options)
433
434
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/plot/plot.pyc
in plot(funcs, *args, **kwds)
3043 xmax = args[1]
3044 args = args[2:]
-> 3045 G = _plot(funcs, (xmin, xmax), *args, **kwds)
3046 elif n == 3:
3047 # if there are three extra args, then pull them out and pass
them as a tuple
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/plot/plot.pyc
in _plot(funcs, xrange, parametric, polar, fill, label, randomize,
**options)
3146 exclude = None
3147 else:
-> 3148 data = generate_plot_points(f, xrange, plot_points,
adaptive_tolerance, adaptive_recursion, randomize)
3149
3150 if parametric:
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/plot/plot.pyc
in generate_plot_points(f, xrange, plot_points, adaptive_tolerance,
adaptive_recursion, randomize, initial_points)
4146 ignore, ranges = setup_for_eval_on_grid([], [xrange],
plot_points)
4147 xmin, xmax, delta = ranges[0]
-> 4148 data = srange(*ranges[0], include_endpoint=True)
4149
4150 random = current_randstate().python_random().random
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/misc/misc.pyc
in srange(start, end, step, universe, check, include_endpoint,
endpoint_tolerance)
974 return range(start, end, step)
975
--> 976 L =
list(xsrange(start,end,step,universe,check,include_endpoint,endpoint_tolerance))
977 return L
978
/opt/sage-4.6.2-linux-32bit-ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-packages/sage/misc/misc.pyc
in xsrange(start, end, step, universe, check, include_endpoint,
endpoint_tolerance)
1061 return xrange(start, end, step)
1062
-> 1063 count = (end-start)/step
1064 if not isinstance(universe, type) and universe.is_exact():
1065 icount = int(math.ceil(float(count)))
ZeroDivisionError: float division
Any help?
Thanks in advance,
Felipo
--
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
URL: http://www.sagemath.org
