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CS_eventually_geometric is now CS_exact
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@tejasvicsr1
tejasvicsr1 committed Jul 31, 2021
1 parent e5c89c9 commit 799e22c
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155 changes: 4 additions & 151 deletions src/sage/data_structures/coefficient_stream.py
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Original file line number Diff line number Diff line change
Expand Up @@ -174,10 +174,8 @@ def __getstate__(self):
TESTS::
sage: from sage.data_structures.coefficient_stream import CoefficientStream_exact
sage: from sage.rings.polynomial.laurent_polynomial_ring import LaurentPolynomialRing
sage: Y = LaurentPolynomialRing(QQ, 'z')
sage: h = CoefficientStream_exact(Y(1), True)
sage: g = CoefficientStream_exact(Y([1, -1, -1]), True)
sage: h = CoefficientStream_exact([1], True)
sage: g = CoefficientStream_exact([1, -1, -1], True)
sage: from sage.data_structures.coefficient_stream import CoefficientStream_div
sage: u = CoefficientStream_div(h, g)
sage: [u[i] for i in range(10)]
Expand Down Expand Up @@ -205,10 +203,8 @@ def __setstate__(self, d):
TESTS::
sage: from sage.data_structures.coefficient_stream import CoefficientStream_exact
sage: from sage.rings.polynomial.laurent_polynomial_ring import LaurentPolynomialRing
sage: Y = LaurentPolynomialRing(QQ, 'z')
sage: h = CoefficientStream_exact(Y(-1), True)
sage: g = CoefficientStream_exact(Y([1, -1]), True)
sage: h = CoefficientStream_exact([-1], True)
sage: g = CoefficientStream_exact([1, -1], True)
sage: from sage.data_structures.coefficient_stream import CoefficientStream_div
sage: u = CoefficientStream_div(h, g)
sage: [u[i] for i in range(10)]
Expand Down Expand Up @@ -457,149 +453,6 @@ def __eq__(self, other):
and self._constant == other._constant)


# class CoefficientStream_exact(CoefficientStream):
# r"""
# Coefficient stream for a series which is known to be eventually geometric.

# INPUT:

# - ``laurent_polynomial`` -- a Laurent polynomial
# - ``is_sparse`` -- boolean; specifies whether the series is sparse
# - ``constant`` -- (default: 0) the eventual constant value
# - ``degree`` -- (default: the degree of ``laurent_polynomial`` plus 1)
# the degree where the coefficient stream becomes ``constant``

# EXAMPLES::

# sage: L.<z> = LazyLaurentSeriesRing(ZZ)
# sage: f = 1 + z^2
# sage: f[2]
# 1

# You can do arithmetic operations with eventually geometric series::

# sage: g = z^3 + 1
# sage: s = f + g
# sage: s[2]
# 1
# sage: s
# 2 + z^2 + z^3
# sage: s = f - g
# sage: s[2]
# 1
# sage: s
# z^2 - z^3
# """

# def __init__(self, laurent_polynomial, is_sparse, constant=None, degree=None):
# """
# Initialize ``self``.

# TESTS::

# sage: R.<z> = LaurentPolynomialRing(QQ)
# sage: from sage.data_structures.coefficient_stream import CoefficientStream_eventually_geometric
# sage: X = CoefficientStream_eventually_geometric(z^2 + z^-1, False)
# sage: [X[i] for i in range(-1,8)]
# [1, 0, 0, 1, 0, 0, 0, 0, 0]
# sage: X = CoefficientStream_eventually_geometric(z^2 + z^-1, True, 5)
# sage: [X[i] for i in range(-1,8)]
# [1, 0, 0, 1, 5, 5, 5, 5, 5]
# sage: X = CoefficientStream_eventually_geometric(z^2 + z^-1, False, 5, 4)
# sage: [X[i] for i in range(-1,8)]
# [1, 0, 0, 1, 0, 5, 5, 5, 5]
# """
# if constant is None:
# constant = ZZ.zero()
# if degree is None:
# if not laurent_polynomial:
# raise ValueError("you must specify the degree for the polynomial 0")
# degree = laurent_polynomial.degree() + 1
# else:
# # Consistency check
# assert not laurent_polynomial or laurent_polynomial.degree() < degree

# self._constant = constant
# self._degree = degree
# self._laurent_polynomial = laurent_polynomial
# if not laurent_polynomial:
# valuation = degree
# else:
# valuation = laurent_polynomial.valuation()
# super().__init__(is_sparse, valuation)

# def __getitem__(self, n):
# """
# Return the coefficient of the term with exponent ``n`` of the series.

# INPUT:

# - ``n`` -- integer; the degree for which the coefficient is required

# EXAMPLES::

# sage: R.<z> = LaurentPolynomialRing(QQ)
# sage: from sage.data_structures.coefficient_stream import CoefficientStream_eventually_geometric
# sage: f = CoefficientStream_eventually_geometric(z^2 + z^-1, False, 3, 10)
# sage: f[2]
# 1
# sage: f[8]
# 0
# sage: f[15]
# 3
# """
# if n >= self._degree:
# return self._constant
# return self._laurent_polynomial[n]

# def valuation(self):
# """
# Return the valuation of the series.

# EXAMPLES::

# sage: L.<z> = LazyLaurentSeriesRing(QQ)
# sage: f = 1 + z + z^2 + z^3
# sage: f.valuation()
# 0
# """
# return self._approximate_valuation

# def __hash__(self):
# """
# Return the hash of ``self``.

# EXAMPLES::

# sage: L.<z> = LazyLaurentSeriesRing(QQ)
# sage: f = 1 + z + z^2 + z^3
# sage: {f: 1}
# {1 + z + z^2 + z^3: 1}
# """
# return hash((self._laurent_polynomial, self._degree, self._constant))

# def __eq__(self, other):
# """
# Test the equality between ``self`` and ``other``.

# INPUT:

# - ``other`` -- a stream for a series which is known to be eventually geometric

# EXAMPLES::

# sage: L.<z> = LazyLaurentSeriesRing(QQ)
# sage: f = 1 + z + z^2 + z^3
# sage: m = 1 + z + z^2 + z^3
# sage: f == m
# True
# """
# return (isinstance(other, type(self))
# and self._degree == other._degree
# and self._laurent_polynomial == other._laurent_polynomial
# and self._constant == other._constant)


class CoefficientStream_coefficient_function(CoefficientStream_inexact):
r"""
Class that returns the elements in the coefficient stream.
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