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Breaking set_precision! changes (#1775)
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@joschmitt
joschmitt authored Sep 17, 2024
1 parent 2116f53 commit ed58b14
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Showing 5 changed files with 85 additions and 124 deletions.
82 changes: 37 additions & 45 deletions src/AbsSeries.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,13 @@ function Base.hash(a::AbsPowerSeriesRingElem, h::UInt)
return b
end

function set_precision!(a::AbsPowerSeriesRingElem, prec::Int)
prec < 0 && throw(DomainError(prec, "Precision must be non-negative"))
a = truncate!(a, prec)
_set_precision_raw!(a, prec)
return a
end

function lift(R::PolyRing{T}, s::AbsPowerSeriesRingElem{T}) where {T}
t = R()
for x = 0:pol_length(s)
Expand Down Expand Up @@ -196,7 +203,7 @@ end
function -(a::AbsPowerSeriesRingElem)
len = length(a)
z = parent(a)()
z = set_precision!(z, precision(a))
z = _set_precision_raw!(z, precision(a))
fit!(z, len)
for i = 1:len
z = setcoeff!(z, i - 1, -coeff(a, i - 1))
Expand All @@ -220,7 +227,7 @@ function +(a::AbsPowerSeriesRingElem{T}, b::AbsPowerSeriesRingElem{T}) where T <
lenz = max(lena, lenb)
z = parent(a)()
fit!(z, lenz)
z = set_precision!(z, prec)
z = _set_precision_raw!(z, prec)
i = 1
while i <= min(lena, lenb)
z = setcoeff!(z, i - 1, coeff(a, i - 1) + coeff(b, i - 1))
Expand Down Expand Up @@ -248,7 +255,7 @@ function -(a::AbsPowerSeriesRingElem{T}, b::AbsPowerSeriesRingElem{T}) where T <
lenz = max(lena, lenb)
z = parent(a)()
fit!(z, lenz)
z = set_precision!(z, prec)
z = _set_precision_raw!(z, prec)
i = 1
while i <= min(lena, lenb)
z = setcoeff!(z, i - 1, coeff(a, i - 1) - coeff(b, i - 1))
Expand Down Expand Up @@ -318,7 +325,7 @@ function *(a::T, b::AbsPowerSeriesRingElem{T}) where {T <: RingElem}
len = length(b)
z = parent(b)()
fit!(z, len)
z = set_precision!(z, precision(b))
z = _set_precision_raw!(z, precision(b))
for i = 1:len
z = setcoeff!(z, i - 1, a*coeff(b, i - 1))
end
Expand All @@ -330,7 +337,7 @@ function *(a::Union{Integer, Rational, AbstractFloat}, b::AbsPowerSeriesRingElem
len = length(b)
z = parent(b)()
fit!(z, len)
z = set_precision!(z, precision(b))
z = _set_precision_raw!(z, precision(b))
for i = 1:len
z = setcoeff!(z, i - 1, a*coeff(b, i - 1))
end
Expand Down Expand Up @@ -361,13 +368,13 @@ function shift_left(x::AbsPowerSeriesRingElem{T}, n::Int) where T <: RingElement
prec = min(prec, max_precision(parent(x)))
if xlen == 0
z = zero(parent(x))
z = set_precision!(z, prec)
z = _set_precision_raw!(z, prec)
return z
end
zlen = min(prec, xlen + n)
z = parent(x)()
fit!(z, zlen)
z = set_precision!(z, prec)
z = _set_precision_raw!(z, prec)
for i = 1:n
z = setcoeff!(z, i - 1, zero(base_ring(x)))
end
Expand All @@ -389,12 +396,12 @@ function shift_right(x::AbsPowerSeriesRingElem{T}, n::Int) where T <: RingElemen
xlen = length(x)
if n >= xlen
z = zero(parent(x))
z = set_precision!(z, max(0, precision(x) - n))
z = _set_precision_raw!(z, max(0, precision(x) - n))
return z
end
z = parent(x)()
fit!(z, xlen - n)
z = set_precision!(z, precision(x) - n)
z = _set_precision_raw!(z, precision(x) - n)
for i = 1:xlen - n
z = setcoeff!(z, i - 1, coeff(x, i + n - 1))
end
Expand All @@ -413,22 +420,7 @@ end
Return $a$ truncated to $n$ terms.
"""
function truncate(a::AbsPowerSeriesRingElem{T}, n::Int) where T <: RingElement
n < 0 && throw(DomainError(n, "n must be >= 0"))
len = length(a)
if precision(a) <= n
return a
end
z = parent(a)()
fit!(z, n)
z = set_precision!(z, n)
for i = 1:min(n, len)
z = setcoeff!(z, i - 1, coeff(a, i - 1))
end
for i = len + 1:n
z = setcoeff!(z, i - 1, zero(base_ring(a)))
end
z = set_length!(z, normalise(z, n))
return z
return truncate!(deepcopy(a), n)
end

###############################################################################
Expand All @@ -447,14 +439,14 @@ function ^(a::AbsPowerSeriesRingElem{T}, b::Int) where T <: RingElement
# special case powers of x for constructing power series efficiently
if b == 0
z = one(parent(a))
z = set_precision!(z, precision(a))
z = _set_precision_raw!(z, precision(a))
return z
elseif precision(a) > 0 && is_gen(a) && b > 0
# arithmetic operators must not introduce new aliasing
return deepcopy(shift_left(a, b - 1))
elseif length(a) == 1
z = parent(a)(coeff(a, 0)^b)
z = set_precision!(z, precision(a))
z = _set_precision_raw!(z, precision(a))
return z
elseif b == 1
return deepcopy(a)
Expand Down Expand Up @@ -619,7 +611,7 @@ function divexact(x::AbsPowerSeriesRingElem{T}, y::AbsPowerSeriesRingElem{T}; ch
end
y = truncate(y, precision(x))
res = parent(x)()
res = set_precision!(res, min(precision(x), precision(y) + valuation(x)))
res = _set_precision_raw!(res, min(precision(x), precision(y) + valuation(x)))
lc = coeff(y, 0)
check && iszero(lc) && error("Not an exact division")
lenr = precision(x)
Expand Down Expand Up @@ -663,7 +655,7 @@ function divexact(x::AbsPowerSeriesRingElem, y::Union{Integer, Rational, Abstrac
lenx = length(x)
z = parent(x)()
fit!(z, lenx)
z = set_precision!(z, precision(x))
z = _set_precision_raw!(z, precision(x))
for i = 1:lenx
z = setcoeff!(z, i - 1, divexact(coeff(x, i - 1), y; check=check))
end
Expand All @@ -675,7 +667,7 @@ function divexact(x::AbsPowerSeriesRingElem{T}, y::T; check::Bool=true) where {T
lenx = length(x)
z = parent(x)()
fit!(z, lenx)
z = set_precision!(z, precision(x))
z = _set_precision_raw!(z, precision(x))
for i = 1:lenx
z = setcoeff!(z, i - 1, divexact(coeff(x, i - 1), y; check=check))
end
Expand All @@ -700,7 +692,7 @@ function Base.inv(a::AbsPowerSeriesRingElem)
a1 = coeff(a, 0)
ainv = parent(a)()
fit!(ainv, precision(a))
ainv = set_precision!(ainv, precision(a))
ainv = _set_precision_raw!(ainv, precision(a))
if precision(a) != 0
ainv = setcoeff!(ainv, 0, divexact(one(R), a1))
end
Expand All @@ -725,20 +717,20 @@ function Base.inv(a::AbsPowerSeriesRingElem{T}) where T <: FieldElement
@assert prec != 0
R = parent(a)
x = R(inv(coeff(a, 0)))
x = set_precision!(x, 1)
x = _set_precision_raw!(x, 1)
la = [prec]
while la[end] > 1
push!(la, div(la[end] + 1, 2))
end
two = R(2)
two = set_precision!(two, prec)
two = _set_precision_raw!(two, prec)
n = length(la) - 1
y = R()
minus_a = -a
while n > 0
# x -> x*(2 - xa) is the lifting recursion
x = set_precision!(x, la[n])
y = set_precision!(y, la[n])
x = _set_precision_raw!(x, la[n])
y = _set_precision_raw!(y, la[n])
y = mul!(y, minus_a, x)
y = add!(y, two)
x = mul!(x, x, y)
Expand Down Expand Up @@ -808,7 +800,7 @@ function _compose_right(a::AbsPowerSeriesRingElem, b::AbsPowerSeriesRingElem)
i -= 1
z = z*b + coeff(a, i - 1)
end
z = set_precision!(z, min(precision(z), valuation(b)*precision(a)))
z = _set_precision_raw!(z, min(precision(z), valuation(b)*precision(a)))
z = set_length!(z, min(pol_length(z), precision(z)))
return z
end
Expand All @@ -825,7 +817,7 @@ function sqrt_classical_char2(a::AbsPowerSeriesRingElem; check::Bool=true)
prec = div(precision(a) + 1, 2)
asqrt = parent(a)()
fit!(asqrt, prec)
asqrt = set_precision!(asqrt, prec)
asqrt = _set_precision_raw!(asqrt, prec)
if check
for i = 1:2:precision(a) - 1 # series must have even exponents
if !iszero(coeff(a, i))
Expand Down Expand Up @@ -867,7 +859,7 @@ function sqrt_classical(a::AbsPowerSeriesRingElem; check::Bool=true)
prec = precision(a) - aval2
asqrt = parent(a)()
fit!(asqrt, prec)
asqrt = set_precision!(asqrt, prec)
asqrt = _set_precision_raw!(asqrt, prec)
for n = 1:aval2
asqrt = setcoeff!(asqrt, n - 1, R())
end
Expand Down Expand Up @@ -946,7 +938,7 @@ Return the derivative of the power series $f$.
"""
function derivative(f::AbsPowerSeriesRingElem{T}) where T <: RingElement
g = parent(f)()
g = set_precision!(g, precision(f) - 1)
g = _set_precision_raw!(g, precision(f) - 1)
len = length(f) - 1
fit!(g, len)
for i = 1:len
Expand All @@ -965,7 +957,7 @@ function integral(f::AbsPowerSeriesRingElem{T}) where T <: RingElement
g = parent(f)()
len = length(f) + 1
fit!(g, len)
g = set_precision!(g, precision(f) + 1)
g = _set_precision_raw!(g, precision(f) + 1)
for i = 1:len - 1
c = coeff(f, i - 1)
if !iszero(c)
Expand All @@ -990,12 +982,12 @@ Return the exponential of the power series $a$.
function Base.exp(a::AbsPowerSeriesRingElem{T}) where T <: RingElement
if iszero(a)
z = one(parent(a))
z = set_precision!(z, precision(a))
z = _set_precision_raw!(z, precision(a))
return z
end
z = parent(a)()
fit!(z, precision(a))
z = set_precision!(z, precision(a))
z = _set_precision_raw!(z, precision(a))
z = setcoeff!(z, 0, exp(coeff(a, 0)))
len = length(a)
C = base_ring(a)()
Expand All @@ -1016,7 +1008,7 @@ end
function Base.exp(a::AbsPowerSeriesRingElem{T}) where T <: FieldElement
if iszero(a)
b = parent(a)(1)
b = set_precision!(b, precision(a))
b = _set_precision_raw!(b, precision(a))
return b
end
R = base_ring(a)
Expand All @@ -1036,8 +1028,8 @@ function Base.exp(a::AbsPowerSeriesRingElem{T}) where T <: FieldElement
n = length(la) - 1
# x -> x*(1 - log(a) + a) is the recursion
while n > 0
x = set_precision!(x, la[n])
one1 = set_precision!(one1, la[n])
x = _set_precision_raw!(x, la[n])
one1 = _set_precision_raw!(one1, la[n])
t = -log(x)
t = add!(t, one1)
t = add!(t, a)
Expand Down
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