Hi,
One of my students was writing a procedure to implement a Midpoint
Riemann Sum in SAGE. The procedure that she devised is given below,
and it looks reasonable enough to me. Unfortunately it generates a
SAGE exception (AttributeError, line 2051 of calculus.py) under
certain bizarre circumstances; try for example a=10,b=20,f=x,n=991
(which works fine) then n=992 with the same a,b,f.
Any assistance would be appreciated. Maybe I don't know Python well
enough? :-) I have verified the exception using both SAGE-2.8.7 on
Fedora Core 7 and SAGE-2.8.13 on Windows.
regards
john perry
Her procedure:
def Midpoint_Riemann_Sums(a,b,f,n):
delta_x = (b-a)/(n*1.0)
result = 0
for i in range(1, n+1):
xi = ((delta_x/2)+a)+(i*delta_x)
result = result+f(xi)*delta_x
return result
The error message:
Traceback (most recent call last):
File "/atlas/perry/sage_notebook/worksheets/apetrinec55/1/code/
71.py", line 4, in <module>
exec
compile(ur'Midpoint_Riemann_Sums(Integer(10),Integer(20),f,Integer(1000))'
+ '\n', '', 'single')
File "/usr/local/sage-2.8.7-fedora_core_7-i686-Linux/data/extcode/
sage/", line 1, in <module>
File "sage_object.pyx", line 87, in sage_object.SageObject.__repr__
File "/usr/local/sage-2.8.7-fedora_core_7-i686-Linux/local/lib/
python2.5/site-packages/sage/calculus/calculus.py", line 2896, in
_repr_
return self.simplify()._repr_(simplify=False)
File "/usr/local/sage-2.8.7-fedora_core_7-i686-Linux/local/lib/
python2.5/site-packages/sage/calculus/calculus.py", line 2051, in
simplify
S =
evaled_symbolic_expression_from_maxima_string(self._maxima_init_())
File "/usr/local/sage-2.8.7-fedora_core_7-i686-Linux/local/lib/
python2.5/site-packages/sage/calculus/calculus.py", line 3044, in
_maxima_init_
return '(%s) %s (%s)' % (ops[0]._maxima_init_(),
...and then several hundred more of that last line.
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