Status: Valid
Owner: ----
Labels: Type-Defect Priority-Medium
New issue 3965 by [email protected]: sum of chebyshev polys fails to
evaluate
http://code.google.com/p/sympy/issues/detail?id=3965
In isympy:
In [1]: var("i")
Out[1]: i
In [2]: e = Sum(chebyshevt(i,x), (i, 0, 2))
In [3]: e
Out[3]:
2
___
╲
╲ chebyshevt(i, x)
╱
╱
‾‾‾
i = 0
In [4]: e.subs(x, 2)
Out[4]:
2
___
╲
╲ chebyshevt(i, 2)
╱
╱
‾‾‾
i = 0
In [5]: e.subs(x, 2).n()
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-5-b69700d83718> in <module>()
----> 1 e.subs(x, 2).n()
/home/ondrej/repos/sympy/sympy/core/evalf.pyc in evalf(self, n, subs, maxn,
chop, strict, quad, verbose)
1282 options['quad'] = quad
1283 try:
-> 1284 result = evalf(self, prec + 4, options)
1285 except NotImplementedError:
1286 # Fall back to the ordinary evalf
/home/ondrej/repos/sympy/sympy/core/evalf.pyc in evalf(x, prec, options)
1182 try:
1183 rf = evalf_table[x.func]
-> 1184 r = rf(x, prec, options)
1185 except KeyError:
1186 try:
/home/ondrej/repos/sympy/sympy/core/evalf.pyc in evalf_sum(expr, prec,
options)
1091 m = n = 2**i * prec
1092 s, err = expr.euler_maclaurin(m=m, n=n, eps=eps,
-> 1093 eval_integral=False)
1094 err = err.evalf()
1095 if err <= eps:
/home/ondrej/repos/sympy/sympy/concrete/summations.pyc in
euler_maclaurin(self, m, n, eps, eval_integral)
389 ga, gb = fpoint(g)
390 term = C.bernoulli(2*k)/C.factorial(2*k)*(gb - ga)
--> 391 if (eps and term and abs(term.evalf(3)) < eps) or (k >
n):
392 break
393 s += term
/home/ondrej/repos/sympy/sympy/core/relational.pyc in __nonzero__(self)
224
225 def __nonzero__(self):
--> 226 raise TypeError("symbolic boolean expression has no truth
value.")
227
228 __bool__ = __nonzero__
TypeError: symbolic boolean expression has no truth value.
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