On 7/31/07, Martin Albrecht <[EMAIL PROTECTED]> wrote: > > > Is this a bug, or am I not using this correctly? > > I'll add the option to construct an MPolynomial_libsingular from a PolyDict.
Too late, I just did it, since I needed it for something else I'm
doing (related to power series over polynomial rings). Martin,
please have a look, since you might be able to improve the patch.
I also added f.polynomial(...) for f a multivariate polynomial, which
sort of fits into the thread of this discussion. This is
a very useful function for certain applications -- it allows you to
view a multivariate polynomial as a single variable polynomial in any
one of its variables.
def polynomial(self, var):
"""
Let var be one of the variables of the parent of self. This
returns self viewed as a unvariate polynomial in var over the
polynomial ring generated by all the other variables of the parent.
EXAMPLES:
sage: R.<x,w,z> = QQ[]
sage: f = x^3 + 3*w*x + w^5 + (17*w^3)*x + z^5
sage: f.polynomial(x)
x^3 + (17*w^3 + 3*w)*x + w^5 + z^5
sage: parent(f.polynomial(x))
Univariate Polynomial Ring in x over Polynomial Ring in w,
z over Rational Field
sage: f.polynomial(w)
w^5 + 17*x*w^3 + 3*x*w + z^5 + x^3
sage: f.polynomial(z)
z^5 + w^5 + 17*x*w^3 + x^3 + 3*x*w
sage: R.<x,w,z,k> = ZZ[]
sage: f = x^3 + 3*w*x + w^5 + (17*w^3)*x + z^5 +x*w*z*k + 5
sage: f.polynomial(x)
x^3 + (17*w^3 + w*z*k + 3*w)*x + w^5 + z^5 + 5
sage: f.polynomial(w)
w^5 + 17*x*w^3 + (x*z*k + 3*x)*w + z^5 + x^3 + 5
sage: f.polynomial(z)
z^5 + x*w*k*z + w^5 + 17*x*w^3 + x^3 + 3*x*w + 5
sage: f.polynomial(k)
x*w*z*k + w^5 + z^5 + 17*x*w^3 + x^3 + 3*x*w + 5
"""
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5537.patch
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