#12173: Update FLINT to 2.3
---------------------------------------------------------------------+------
Reporter: mhansen |
Owner: tbd
Type: enhancement |
Status: needs_work
Priority: major |
Milestone: sage-5.10
Component: packages: standard |
Resolution:
Keywords: flint spkg | Work
issues:
Report Upstream: N/A |
Reviewers: John Cremona, Jeroen Demeyer
Authors: Mike Hansen, Fredrik Johansson, Jean-Pierre Flori |
Merged in:
Dependencies: sage-5.9.beta5 |
Stopgaps:
---------------------------------------------------------------------+------
Comment (by burcin):
Here are some comments after reading attachment:trac_12173-fixes-v6.patch.
I don't understand this hunk:
{{{
diff --git a/sage/libs/flint/fmpz_poly.pyx b/sage/libs/flint/fmpz_poly.pyx
--- a/sage/libs/flint/fmpz_poly.pyx
+++ b/sage/libs/flint/fmpz_poly.pyx
@@ -53,7 +53,7 @@
cdef long c
cdef Integer w
if PY_TYPE_CHECK(v, str):
- if fmpz_poly_set_str(self.poly, v):
+ if not fmpz_poly_set_str(self.poly, v):
return
else:
raise ValueError, "Unable to create Fmpz_poly from that
string."
}}}
`nmod_poly_pow(..., 2)` should be used below instead of `nmod_poly_mul()`.
{{{
diff --git a/sage/libs/flint/nmod_poly_linkage.pxi
b/sage/libs/flint/nmod_poly_linkage.pxi
--- a/sage/libs/flint/nmod_poly_linkage.pxi
+++ b/sage/libs/flint/nmod_poly_linkage.pxi
@@ -496,7 +495,7 @@
elif e == 1:
nmod_poly_set(res, x)
elif e == 2:
- nmod_poly_sqr(res, x)
+ nmod_poly_mul(res, x, x)
else:
if res == x:
nmod_poly_set(tmp, x)
@@ -510,7 +509,7 @@
nmod_poly_set_coeff_ui(res, 0, 1)
e = e >> 1
while(e != 0):
- nmod_poly_sqr(pow2, pow2)
+ nmod_poly_mul(pow2, pow2, pow2)
if e % 2:
nmod_poly_mul(res, res, pow2)
e = e >> 1
}}}
This seems to remove the fast exit path:
{{{
diff --git a/sage/rings/fraction_field_FpT.pyx
b/sage/rings/fraction_field_FpT.pyx
--- a/sage/rings/fraction_field_FpT.pyx
+++ b/sage/rings/fraction_field_FpT.pyx
@@ -688,26 +688,34 @@
"""
if nmod_poly_degree(self._numer) == -1:
return self
- if not nmod_poly_sqrt_check(self._numer) or not
nmod_poly_sqrt_check(self._denom):
- return None
}}}
Fredrik says that FLINT also does the same checks in `nmod_poly_sqrt()`,
but some memory allocations are performed by the time we get to that
point. If the input to this function is not a perfect square most of the
time, then IMHO removing these checks will introduce a performance
regression.
In the same hunk as above:
{{{
+ # Make denominator monic
+ a = nmod_poly_leading(denom)
+ if a != 1:
+ a = mod_inverse_int(a, self.p)
+ nmod_poly_scalar_mul_nmod(numer, numer, a)
+ nmod_poly_scalar_mul_nmod(denom, denom, a)
+ # Choose numerator with smaller leading coefficient
+ a = nmod_poly_leading(numer)
+ if a > self.p - a:
+ nmod_poly_neg(numer, numer)
}}}
Is this necessary? If the input is normalized, the denominator will have 1
as a leading coefficient anyway. If we really want to normalize, the
`normalize()` method in the same file should be used.
`_nmod_poly_set_coeff_ui()` was removed from FLINT2. Removing the
underscore introduces a potential branch for each function call. Shall we
implement our own underscore version?
{{{
diff --git a/sage/rings/polynomial/polynomial_zmod_flint.pyx
b/sage/rings/polynomial/polynomial_zmod_flint.pyx
--- a/sage/rings/polynomial/polynomial_zmod_flint.pyx
+++ b/sage/rings/polynomial/polynomial_zmod_flint.pyx
@@ -157,17 +170,47 @@
<snip>
+ sig_on()
for i from 0 <= i < length:
- _nmod_poly_set_coeff_ui(&self.x, i, l_in[i])
- # we need to set the length manually, we used
_nmod_poly_set_coeff_ui
- self.x.length = length
+ nmod_poly_set_coeff_ui(&self.x, i, l_in[i])
+ sig_off()
+ return 0
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12173#comment:311>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac?hl=en.
For more options, visit https://groups.google.com/groups/opt_out.
