id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
9130 Access to beta function kcrisman burcin "Although Maxima has the beta function, Sage doesn't:
{{{
sage: a, b, c = var('a b c')
sage: assume(a > 0)
sage: assume(b > 0)
sage: x = var('x')
sage: beta_dist = x**(a-1) * (1 - x)**(b-1)
sage: c = integral(beta_dist, x, 0, 1)
sage: c
beta(a, b)
sage: c(a=.5,b=.5)
beta(0.500000000000000, 0.500000000000000)
sage: c(a=.5,b=.5).n()
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
/Users/karl-dietercrisman/ in ()
/Users/karl-dietercrisman/Desktop/sage-4.4.2/local/lib/python2.6/site-packages/sage/symbolic/expression.so in sage.symbolic.expression.Expression.n (sage/symbolic/expression.cpp:17042)()
TypeError: cannot evaluate symbolic expression numerically
}}}
This *is* is Ginac, though, and there is even room for defining it in symbolic/expression.pyx . It probably is also included in some of our other libraries, as a standard special function.
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Apply
* [attachment:trac_9130-beta_function.patch]
* [attachment:trac_9130-py_float_segfault.take2.patch]" enhancement positive_review major sage-5.0 symbolics special function, pynac, sd35.5 benjaminfjones Karen T. Kohl, Burcin Erocal Benjamin Jones, Burcin Erocal N/A