From 00c35cdfa9e4328f099f6f95a00ab29e2cc2037f Mon Sep 17 00:00:00 2001 From: Ralf Stephan Date: Tue, 1 Dec 2015 10:21:41 +0100 Subject: [PATCH] 17402: add SymbolicSeries.power_series --- src/sage/symbolic/series.pyx | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/src/sage/symbolic/series.pyx b/src/sage/symbolic/series.pyx index e84ae74e714..9e8cca1c732 100644 --- a/src/sage/symbolic/series.pyx +++ b/src/sage/symbolic/series.pyx @@ -232,3 +232,21 @@ cdef class SymbolicSeries(Expression): ret[c[1]] = c[0] return ret + def power_series(self, base_ring): + """ + Return algebraic power series associated to this symbolic + series. The coefficients must be coercible to the base ring. + + EXAMPLES:: + + sage: ex=(gamma(1-x)).series(x,3); ex + 1 + (euler_gamma)*x + (1/2*euler_gamma^2 + 1/12*pi^2)*x^2 + Order(x^3) + sage: g=ex.power_series(SR); g + 1 + euler_gamma*x + (1/2*euler_gamma^2 + 1/12*pi^2)*x^2 + O(x^3) + sage: g.parent() + Power Series Ring in x over Symbolic Ring + """ + from sage.rings.all import PowerSeriesRing + R = PowerSeriesRing(base_ring, names=str(self.default_variable())) + return R(self.list(), self.degree(self.default_variable())) +