def _to_s(self, part):
"""
Returns a function which gives the coefficient of a partition in
the Schur expansion of self(part).
EXAMPLES::
sage: Ht = MacdonaldPolynomialsHt(QQ)
sage: f21 = Ht._to_s(Partition([2,1]))
sage: [f21(part) for part in Partitions(3)]
[1, q + t, q*t]
sage: f22 = Ht._to_s(Partition([2,2]))
sage: [f22(part) for part in Partitions(4)]
[1, q*t + q + t, q^2 + t^2, q^2*t + q*t^2 + q*t, q^2*t^2]
"""
q, t = QQqt.gens()
s = sfa.SFASchur(QQqt)
J = MacdonaldPolynomialsJ(QQ)
res = 0
for p in sage.combinat.partition.Partitions(sum(part)):
res += (J(part).scalar_t(s(p), t)) * s(p)
res = res.map_coefficients(lambda c: c.subs(t=1 / t))
res *= t**part.weighted_size()
f = lambda part2: res.coefficient(part2)
return f
def scalar(self, x):
"""
Returns standard scalar product between self and s.
This is the default implementation that converts both self and x
into Schur functions and performs the scalar product that basis.
EXAMPLES::
sage: HLP = HallLittlewoodP(QQ)
sage: HLQ = HallLittlewoodQ(QQ)
sage: HLQp = HallLittlewoodQp(QQ)
sage: HLP([2]).scalar(HLQp([2]))
1
sage: HLP([2]).scalar(HLQp([1,1]))
0
"""
sp = self.parent()
xp = x.parent()
BR = sp.base_ring()
s = sfa.SFASchur(BR)
s_self = s(self)
s_x = s(x)
return s_self.scalar(s_x)
def __init__(self, R, t=None):
"""
TESTS::
sage: HallLittlewoodP(QQ)
Hall-Littlewood polynomials in the P basis over Fraction Field of Univariate Polynomial Ring in t over Rational Field
sage: HallLittlewoodP(QQ,t=2)
Hall-Littlewood polynomials in the P basis with t=2 over Rational Field
"""
if t is None:
R = R['t'].fraction_field()
self.t = R.gen()
elif t not in R:
raise ValueError, "t (=%s) must be in R (=%s)" % (t, R)
else:
self.t = R(t)
self._name += " with t=%s" % self.t
sfa.SymmetricFunctionAlgebra_generic.__init__(self, R)
# print self, self._s
# This coercion is broken: HLP = HallLittlewoodP(QQ); HLP(HLP._s[1])
# Bases defined by orthotriangularity should inherit from some
# common category BasesByOrthotriangularity (shared with Jack, HL, orthotriang, Mcdo)
if hasattr(self, "_s_cache"):
self._s = sfa.SFASchur(R)
# temporary until Hom(GradedHopfAlgebrasWithBasis work better)
category = sage.categories.all.ModulesWithBasis(self.base_ring())
self.register_coercion(
SetMorphism(Hom(self._s, self, category), self._s_to_self))
self._s.register_coercion(
SetMorphism(Hom(self, self._s, category), self._self_to_s))
def __init__(self, R, q=None, t=None):
"""
EXAMPLES::
sage: MacdonaldPolynomialsP(QQ)
Macdonald polynomials in the P basis over Fraction Field of Multivariate Polynomial Ring in q, t over Rational Field
sage: MacdonaldPolynomialsP(QQ,t=2)
Macdonald polynomials in the P basis with t=2 over Fraction Field of Univariate Polynomial Ring in q over Rational Field
sage: MacdonaldPolynomialsP(QQ,q=2)
Macdonald polynomials in the P basis with q=2 over Fraction Field of Univariate Polynomial Ring in t over Rational Field
sage: MacdonaldPolynomialsP(QQ,q=2,t=2)
Macdonald polynomials in the P basis with q=2 and t=2 over Rational Field
"""
#Neither q nor t are specified
if t is None and q is None:
R = R['q,t'].fraction_field()
self.q, self.t = R.gens()
elif t is not None and q is None:
if t not in R:
raise ValueError, "t (=%s) must be in R (=%s)" % (t, R)
self.t = R(t)
self._name += " with t=%s" % self.t
R = R['q'].fraction_field()
self.q = R.gen()
elif t is None and q is not None:
if q not in R:
raise ValueError, "q (=%s) must be in R (=%s)" % (q, R)
self.q = R(q)
self._name += " with q=%s" % self.q
R = R['t'].fraction_field()
self.t = R.gen()
else:
if t not in R or q not in R:
raise ValueError
self.q = R(q)
self.t = R(t)
self._name += " with q=%s and t=%s" % (self.q, self.t)
sfa.SymmetricFunctionAlgebra_generic.__init__(self, R)
# Bases defined by orthotriangularity should inherit from some
# common category BasesByOrthotriangularity (shared with Jack, HL, orthotriang, Mcdo)
if hasattr(self, "_s_cache"):
self._s = sfa.SFASchur(R)
# temporary until Hom(GradedHopfAlgebrasWithBasis work better)
category = sage.categories.all.ModulesWithBasis(self.base_ring())
self.register_coercion(
SetMorphism(Hom(self._s, self, category), self._s_to_self))
self._s.register_coercion(
SetMorphism(Hom(self, self._s, category), self._self_to_s))
def qt_kostka(lam, mu):
"""
Returns the `K_{\lambda\mu}(q,t)` by computing the change
of basis from the Macdonald H basis to the Schurs.
EXAMPLES::
sage: from sage.combinat.sf.macdonald import qt_kostka
sage: qt_kostka([2,1,1],[1,1,1,1])
t^3 + t^2 + t
sage: qt_kostka([1,1,1,1],[2,1,1])
q
sage: qt_kostka([1,1,1,1],[3,1])
q^3
sage: qt_kostka([1,1,1,1],[1,1,1,1])
1
sage: qt_kostka([2,1,1],[2,2])
q^2*t + q*t + q
sage: qt_kostka([2,2],[2,2])
q^2*t^2 + 1
sage: qt_kostka([4],[3,1])
t
sage: qt_kostka([2,2],[3,1])
q^2*t + q
sage: qt_kostka([3,1],[2,1,1])
q*t^3 + t^2 + t
sage: qt_kostka([2,1,1],[2,1,1])
q*t^2 + q*t + 1
sage: qt_kostka([2,1],[1,1,1,1])
0
"""
lam = sage.combinat.partition.Partition(lam)
mu = sage.combinat.partition.Partition(mu)
R = QQ['q,t']
if lam.size() != mu.size():
return R(0)
if (lam, mu) in _qt_kostka_cache:
return _qt_kostka_cache[(lam, mu)]
H = MacdonaldPolynomialsH(QQ)
s = sfa.SFASchur(H.base_ring())
parts = sage.combinat.partition.Partitions(mu.size())
for p2 in parts:
res = s(H(p2))
for p1 in parts:
_qt_kostka_cache[(p1, p2)] = R(res.coefficient(p1).numerator())
return _qt_kostka_cache[(lam, mu)]
def __init__(self, R, q=None, t=None):
"""
TESTS::
sage: S = MacdonaldPolynomialsS(QQ)
sage: S == loads(dumps(S))
True
"""
self._name = "Macdonald polynomials in the S basis"
self._prefix = "McdS"
MacdonaldPolynomials_generic.__init__(self, R, q, t)
self._s = sfa.SFASchur(self.base_ring())
self._self_to_s_cache = S_to_s_cache
self._s_to_self_cache = s_to_S_cache
_set_cache(cache_s, self)
def __init__(self, R, q=None, t=None):
"""
TESTS::
sage: Ht = MacdonaldPolynomialsHt(QQ)
sage: Ht == loads(dumps(Ht))
True
"""
self._name = "Macdonald polynomials in the Ht basis"
self._prefix = "McdHt"
MacdonaldPolynomials_generic.__init__(self, R, q, t)
self._s = sfa.SFASchur(self.base_ring())
self._self_to_s_cache = ht_to_s_cache
self._s_to_self_cache = s_to_ht_cache
self._J = MacdonaldPolynomialsJ(self.base_ring(), self.q, self.t)
_set_cache(cache_ht, self)
def _to_s(self, part):
"""
Returns a function which gives the coefficient of a partition in
the Schur expansion of self(part).
EXAMPLES::
sage: H = MacdonaldPolynomialsH(QQ)
sage: f21 = H._to_s(Partition([2,1]))
sage: [f21(part) for part in Partitions(3)]
[t, q*t + 1, q]
"""
q, t = QQqt.gens()
s = sfa.SFASchur(QQqt)
res = s(self._Ht(part)).map_coefficients(lambda c: c.subs(t=1 / t))
res *= t**part.weighted_size()
f = lambda part2: res.coefficient(part2)
return f
def __init__(self, R, k, t=None):
"""
EXAMPLES::
sage: kSchurFunctions(QQ, 3).base_ring()
Univariate Polynomial Ring in t over Rational Field
sage: kSchurFunctions(QQ, 3, t=1).base_ring()
Rational Field
sage: ks3 = kSchurFunctions(QQ, 3)
sage: ks3 == loads(dumps(ks3))
True
"""
self.k = k
self._name = "k-Schur Functions at level %s"%k
self._prefix = "ks%s"%k
self._element_class = kSchurFunctions_t.Element
if t is None:
R = R['t']
self.t = R.gen()
elif t not in R:
raise ValueError, "t (=%s) must be in R (=%s)"%(t,R)
else:
self.t = R(t)
if str(t) != 't':
self._name += " with t=%s"%self.t
self._s_to_self_cache = s_to_k_cache.get(k, {})
self._self_to_s_cache = k_to_s_cache.get(k, {})
# This is an abuse, since kschur functions do not form a basis of Sym
sfa.SymmetricFunctionAlgebra_generic.__init__(self, R)
# so we need to take some counter measures
self._basis_keys = sage.combinat.partition.Partitions(NonNegativeIntegers(), max_part=k)
self._s = sfa.SFASchur(self.base_ring())
# temporary until Hom(GradedHopfAlgebrasWithBasis work better)
category = sage.categories.all.ModulesWithBasis(self.base_ring())
# This really should be a conversion, not a coercion (it can fail)
self .register_coercion(SetMorphism(Hom(self._s, self, category), self._s_to_self))
self._s.register_coercion(SetMorphism(Hom(self, self._s, category), self._self_to_s))
def expand(self, n, alphabet='x'):
"""
Expands the symmetric function as a symmetric polynomial in `n`
variables.
EXAMPLES::
sage: HLP = HallLittlewoodP(QQ)
sage: HLQ = HallLittlewoodQ(QQ)
sage: HLQp = HallLittlewoodQp(QQ)
sage: HLP([2]).expand(2)
x0^2 + (-t + 1)*x0*x1 + x1^2
sage: HLQ([2]).expand(2)
(-t + 1)*x0^2 + (t^2 - 2*t + 1)*x0*x1 + (-t + 1)*x1^2
sage: HLQp([2]).expand(2)
x0^2 + x0*x1 + x1^2
"""
sp = self.parent()
BR = sp.base_ring()
s = sfa.SFASchur(BR)
return s(self).expand(n, alphabet=alphabet)
def _to_s(self, part):
"""
Returns a function which gives the coefficient of a partition in
the Schur expansion of self(part).
EXAMPLES::
sage: S = MacdonaldPolynomialsS(QQ)
sage: S2 = S._to_s(Partition([2]))
sage: S2(Partition([2]))
-t + 1
sage: S2(Partition([1,1]))
t^2 - t
"""
#Covert to the power sum
p = sfa.SFAPower(QQqt)
s = sfa.SFASchur(QQqt)
p_x = p(s(part))
t = self.t
f = lambda m, c: (m, c * prod([(1 - t**k) for k in m]))
res = s(p_x.map_item(f))
f = lambda part2: res.coefficient(part2)
return f
