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= Sage 3.4.1 Release Tour =

Sage 3.4.1 was released on FIXME. For the official, comprehensive release note, please refer to [[http://www.sagemath.org/src/announce/sage-3.4.1.txt|sage-3.4.1.txt]]. A nicely formatted version of this release tour can be found at FIXME. The following points are some of the foci of this release:

 * Merging improvements during the Sage Days 13 coding sprint.
 * Other bug fixes post Sage 3.4.
## page was renamed from sage-3.4.1
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== Algebra ==


 * Optimized {{{is_primitive()}}} method (Ryan Hinton) -- The method {{{is_primitive()}}} in {{{sage/rings/polynomial/polynomial_element.pyx}}} is used for determining whether or not a polynomial is primitive over a finite field. Prime divisors are calculated during the test for polynomial primitivity. Where n is large, calculating those prime divisors can dominate the running time of the test. The {{{is_primitive()}}} method now has the optional argument {{{n_prime_divs}}} for providing precomputed prime divisors. This optional argument can result in a performance improvement of up to 4x. On the machine sage.math, one has the following timing statistics:
 {{{
sage: R.<x> = PolynomialRing(GF(2), 'x')
sage: nn = 128
sage: max_order = 2^nn - 1
sage: pdivs = max_order.prime_divisors()
sage: poly = R.random_element(nn)
sage: while not (poly.degree()==nn and poly.is_primitive(max_order, pdivs)):
....: poly = R.random_element(nn)
....:
sage: %timeit poly.is_primitive() # without n_prime_divs optional argument
10 loops, best of 3: 285 ms per loop
sage: %timeit poly.is_primitive(max_order, pdivs) # with n_prime_divs optional argument
10 loops, best of 3: 279 ms per loop
sage:
sage: nn = 256
sage: max_order = 2^nn - 1
sage: pdivs = max_order.prime_divisors()
sage: poly = R.random_element(nn)
sage: while not (poly.degree()==nn and poly.is_primitive(max_order, pdivs)):
....: poly = R.random_element(nn)
....:
sage: %timeit poly.is_primitive() # without n_prime_divs optional argument
10 loops, best of 3: 3.22 s per loop
sage: %timeit poly.is_primitive(max_order, pdivs) # with n_prime_divs optional argument
10 loops, best of 3: 700 ms per loop
 }}}


 * Speed-up the method {{{order_from_multiple()}}} (John Cremona) -- For groups of prime order n, every non-identity element has order n. The previous implementation of the method {{{order_from_multiple()}}} computes g^n twice when g is not the identity and n is prime. Such double computation is now avoided. Now for each prime p dividing the given multiple of the order, we avoid the last multiplication/powering by p, hence saving some computation time whenever the p-exponent of the order is maximal. The new implementation of {{{order_from_multiple()}}} results in a performance improvement of up to 25%. Here are some timing statistics obtained using the machine sage.math:
 {{{
# BEFORE
sage: F = GF(2^1279, 'a')
sage: n = F.cardinality() - 1 # Mersenne prime
sage: order_from_multiple(F.random_element(), n, [n], operation='*') == n
True
sage: %timeit order_from_multiple(F.random_element(), n, [n], operation='*') == n
10 loops, best of 3: 63.7 ms per loop


# AFTER
sage: F = GF(2^1279, 'a')
sage: n = F.cardinality() - 1 # Mersenne prime
sage: %timeit order_from_multiple(F.random_element(), n, [n], operation='*') == n
10 loops, best of 3: 47.2 ms per loop
 }}}


 * Speed-up in irreducibility test (Ryan Hinton) -- For polynomials over the finite field {{{GF(2)}}}, the test for irreducibility is now up to 40,000 times faster than previously. On a 64-bit Debian/squeeze machine with Core 2 Duo running at 2.33 GHz, one has the following timing improvements:
 {{{
# BEFORE
sage: P.<x> = GF(2)[]
sage: f = P.random_element(1000)
sage: %timeit f.is_irreducible()
10 loops, best of 3: 948 ms per loop
sage:
sage: f = P.random_element(10000)
sage: %time f.is_irreducible()
# gave up because it took minutes!


# AFTER
sage: P.<x> = GF(2)[]
sage: f = P.random_element(1000)
sage: %timeit f.is_irreducible()
10000 loops, best of 3: 22.7 µs per loop
sage:
sage: f = P.random_element(10000)
sage: %timeit f.is_irreducible()
1000 loops, best of 3: 394 µs per loop
sage:
sage: f = P.random_element(100000)
sage: %timeit f.is_irreducible()
100 loops, best of 3: 10.4 ms per loop
 }}}
 Furthermore, on Debian 5.0 Lenny with kernel 2.6.24-1-686, an Intel(R) Celeron(R) CPU running at 2.00GHz with 1.0GB of RAM, one has the following timing statistics:
 {{{
# BEFORE
sage: P.<x> = GF(2)[]
sage: f = P.random_element(1000)
sage: %timeit f.is_irreducible()
10 loops, best of 3: 1.14 s per loop
sage:
sage: f = P.random_element(10000)
sage: %time f.is_irreducible()
CPU times: user 4972.13 s, sys: 2.83 s, total: 4974.95 s
Wall time: 5043.02 s
False


# AFTER
sage: P.<x> = GF(2)[]
sage: f = P.random_element(1000)
sage: %timeit f.is_irreducible()
10000 loops, best of 3: 40.7 µs per loop
sage:
sage: f = P.random_element(10000)
sage: %timeit f.is_irreducible()
1000 loops, best of 3: 930 µs per loop
sage:
sage:
sage: f = P.random_element(100000)
sage: %timeit f.is_irreducible()
10 loops, best of 3: 27.6 ms per loop
 }}}


== Algebraic Geometry ==


 * Refactor {{{dimension()}}} method for schemes (Alex Ghitza) -- Implement methods {{{dimension_absolute()}}} and {{{dimension_relative()}}}, where {{{dimension()}}} is an alias for {{{dimension_absolute()}}}. Here are some examples of using {{{dimension_absolute()}}} and {{{dimension()}}}:
 {{{
sage: A2Q = AffineSpace(2, QQ)
sage: A2Q.dimension_absolute()
2
sage: A2Q.dimension()
2
 }}}
 And here's an example demonstrating the use of {{{dimension_relative()}}}:
 {{{
sage: S = Spec(ZZ)
sage: S.dimension_relative()
0
 }}}


 * Plotting affine and projective curves (Alex Ghitza) -- Improving the plotting usability so it is now easier to plot affine and projective curves. For example, we can plot a [[attachment:5-nodal curve]] of degree 11:
 {{{
sage: R.<x, y> = ZZ[]
sage: C = Curve(32*x^2 - 2097152*y^11 + 1441792*y^9 - 360448*y^7 + 39424*y^5 - 1760*y^3 + 22*y - 1)
sage: C.plot((x, -1, 1), (y, -1, 1), plot_points=400)
 }}}
 Now we plot an [[attachment:elliptic curve]]:
 {{{
sage: E = EllipticCurve('101a')
sage: C = Curve(E)
sage: C.plot()
 }}}


== Basic Arithmetic ==


 * Speed-up in dividing a polynomial by an integer (Burcin Erocal) -- Dividing a polynomial by an integer is now up to 6x faster than previously. On Debian 5.0 Lenny with kernel 2.6.24-1-686, an Intel(R) Celeron(R) CPU running at 2.00GHz with 1.0GB of RAM, one has the following timing statistics:
 {{{
# BEFORE
sage: R.<x> = ZZ["x"]
sage: f = 389 * R.random_element(1000)
sage: timeit("f//389")
625 loops, best of 3: 312 µs per loop


# AFTER
sage: R.<x> = ZZ["x"]
sage: f = 389 * R.random_element(1000)
sage: timeit("f//389")
625 loops, best of 3: 48.3 µs per loop
 }}}


 * New {{{fast_float}}} supports more datatypes with improved performance (Carl Witty) -- A rewrite of {{{fast_float}}} to support multiple types. Here, we get accelerated evaluation over {{{RealField(k)}}} as well as {{{RDF}}}, real double field. As compared with the previous {{{fast_float}}}, improved performance can range from 2% faster to more than 2x as fast. An extended list of benchmark details is available at [[http://trac.sagemath.org/sage_trac/ticket/5093|ticket 5093]].


 * Complex double fast callable interpreter (Robert Bradshaw) -- Support for complex double floating point (CDF). The new interpreter is implemented in the class {{{CDFInterpreter}}} of {{{sage/ext/gen_interpreters.py}}}.


 * Speed-up the function {{{solve_mod()}}} (Wilfried Huss) -- Performance improvement for the function {{{solve_mod()}}} is now up to 5x when solving an equation or a list of equations modulo a given integer modulus. On the machine sage.math, we have the following timing statistics:
 {{{
# BEFORE

sage: x, y = var('x,y')
sage: time solve_mod([x^2 + 2 == x, x^2 + y == y^2], 14)
CPU times: user 0.01 s, sys: 0.02 s, total: 0.03 s
Wall time: 0.18 s
[(4, 2), (4, 6), (4, 9), (4, 13)]
sage:
sage: x,y,z = var('x,y,z')
sage: time solve_mod([x^5 + y^5 == z^5], 3)
CPU times: user 0.01 s, sys: 0.00 s, total: 0.01 s
Wall time: 0.10 s

[(0, 0, 0),
 (0, 1, 1),
 (0, 2, 2),
 (1, 0, 1),
 (1, 1, 2),
 (1, 2, 0),
 (2, 0, 2),
 (2, 1, 0),
 (2, 2, 1)]


# AFTER

sage: x, y = var('x,y')
sage: time solve_mod([x^2 + 2 == x, x^2 + y == y^2], 14)
CPU times: user 0.03 s, sys: 0.01 s, total: 0.04 s
Wall time: 0.16 s
[(4, 2), (4, 6), (4, 9), (4, 13)
sage:
sage: x,y,z = var('x,y,z')
sage: time solve_mod([x^5 + y^5 == z^5], 3)
CPU times: user 0.01 s, sys: 0.01 s, total: 0.02 s
Wall time: 0.02 s

[(0, 0, 0),
 (0, 1, 1),
 (0, 2, 2),
 (1, 0, 1),
 (1, 1, 2),
 (1, 2, 0),
 (2, 0, 2),
 (2, 1, 0),
 (2, 2, 1)]
 }}}


 * Optimized binomial function when an input is real or complex floating point (Dan Drake, William Stein) -- The function {{{binomial()}}} for returning the binomial coefficients is now much faster. In some cases, speed efficiency can be up to 4000x. Here are some timing statistics obtained using the machine sage.math:
 {{{
# BEFORE

sage: x, y = 1140000.78, 420000
sage: %timeit binomial(x, y)
10 loops, best of 3: 1.19 s per loop
sage:
sage: x, y = RR(pi^5), 10
sage: %timeit binomial(x, y)
10000 loops, best of 3: 28.2 µs per loop
sage:
sage: x, y = RR(pi^15), 500
sage: %timeit binomial(x, y)
1000 loops, best of 3: 799 µs per loop
sage:
sage: x, y = RealField(500)(1729000*sqrt(2)), 17000
sage: %timeit binomial(x, y)
10 loops, best of 3: 34.4 ms per loop


# AFTER

sage: x, y = 1140000.78, 420000
sage: %timeit binomial(x, y)
1000 loops, best of 3: 297 µs per loop
sage:
sage: x, y = RR(pi^5), 10
sage: %timeit binomial(x, y)
10000 loops, best of 3: 189 µs per loop
sage:
sage: x, y = RR(pi^15), 500
sage: %timeit binomial(x, y)
1000 loops, best of 3: 335 µs per loop
sage:
sage: x, y = RealField(500)(1729000*sqrt(2)), 17000
sage: %timeit binomial(x, y)
1000 loops, best of 3: 692 µs per loop
 }}}


 * Enhanced {{{nth_root()}}} in {{{ZZ}}} and {{{QQ}}} and related utilities (John Cremona) -- Some consistency in the method {{{nth_root()}}} of {{{ZZ}}} and {{{QQ}}}. There are also some new utility methods for the rational numbers:
  1. {{{prime_to_S_part(self, S=[])}}} -- Returns {{{self}}} with all powers of all primes in S removed.
  1. {{{is_nth_power(self, int n)}}} -- Returns {{{True}}} if {{{self}}} is an n-th power; else {{{False}}}.
  1. {{{is_S_integral(self, S=[])}}} -- Determine if the rational number is S-integral.
  1. {{{is_S_unit(self, S=None)}}} -- Determine if the rational number is an S-unit.


== Build ==


== Calculus ==


 * Deprecate the calling of symbolic functions with unnamed arguments (Carl Witty, Michael Abshoff) -- Previous releases of Sage supported symbolic functions with "no arguments". This style of constructing symbolic functions is now deprecated. For example, previously Sage allowed for defining a symbolic function in the following way
 {{{
f2 = 5 - x^2 # bad; this is deprecated
 }}}
 But users are encouraged to explicitly declare the variables used in a symolic function. For instance, the following is encouraged:
 {{{
sage: x,y = var("x, y") # explicitly declare your variables
sage: f(x, y) = x^2 + y^2 # this syntax is encouraged
 }}}



== Coercion ==


== Combinatorics ==


 * Enhancements to the {{{Subsets}}} and {{{Subwords}}} modules (Florent Hivert) -- Numerous enhancements to the modules {{{Subsets}}} and {{{Subwords}}} include:
  1. An implementation of subsets for finite multisets, i.e. sets with repetitions.
  1. Adding the method {{{__contains__}}} for {{{Subsets}}} and {{{Subwords}}}.
 Here's an example for working with multisets:
 {{{
sage: S = Subsets([1, 2, 2], submultiset=True); S
SubMultiset of [1, 2, 2]
sage: S.list()
[[], [1], [2], [1, 2], [2, 2], [1, 2, 2]]
sage: Set([1,2]) in S # this uses __contains__ in Subsets
True
sage: Set([]) in S
True
sage: Set([3]) in S
False
 }}}
 And here's an example of using {{{__contains__}}} with {{{Subwords}}}:
 {{{
sage: [] in Subwords([1,2,3,4,3,4,4])
True
sage: [2,3,3,4] in Subwords([1,2,3,4,3,4,4])
True
sage: [2,3,3,1] in Subwords([1,2,3,4,3,4,4])
False
 }}}


 * Fix and enhancements to permutations (Sebastien Labbe) -- This corrects the Robinson-Schensted algorithm on trivial permutations. It implements the inverse Robinson-Schensted algorithm:
 {{{
sage: Permutation((Tableau([[1,2,4],[3]]), Tableau([[1,3,4],[2]])))
[3, 1, 2, 4]
sage: Permutation(([[1,2,4],[3]], [[1,3,4],[2]]))
[3, 1, 2, 4]
 }}}
 And it works for arbitrary words (with semi-standard tableaux):
 {{{
sage: Permutation(([[1,2,2],[3]], [[1,3,4],[2]]))
[3, 1, 2, 2]
 }}}


 * First pass of cleanup of the interface of combinatorial classes (Florent Hivert) -- Before the patch, the interface of combinatorial classes had two problems:
  1. There were two redundant ways to get the number of elements {{{len(C)}}} and {{{C.count()}}}. Moreover {{{len}}} must return a plain {{{int}}} where we want an arbitrary large number and even {{{infinity}}};
  1. There were two redundant ways to get an iterator for the elements {{{C.iterator()}}} and {{{iter(C)}}} (allowing for {{{for c in C: ...}}}) via {{{C.__iter__}}}.
 
 The patch standardize those issues to:
  1. {{{C.cardinality()}}} which is more explicit and consistent with many other Sage libraries;
  1. {{{iter(C)}}} / {{{for x in C:}}} via {{{C.__iter__}}} which is clearly more Pythonic.
 
  The functions {{{iterator()}}} and {{{count()}}} are deprecated (with a warning), but will be removed in a later release. On the other hand, there was no way to keep backward compatibility for {{{len}}}. Indeed, many of function such as {{{list / filter / map}}} try silently to call {{{len}}}, which would have caused miriads of warnings to be issued in seemingly unrelated places. So it was decided to simply remove it and issue an error, suggesting to call {{{cardinality}}} instead.


 * New class {{{IntegerListLex}}} for generating integer lists (Nicolas M. Thiery, Florent Hivert) -- The new class provides a Constant Amortized Time iterator through the combinatorial classes of integer lists. For example, we create the combinatorial class of lists of length 3 and sum 2 as follows:
 {{{
sage: C = IntegerListsLex(2, length=3); C
Integer lists of sum 2 satisfying certain constraints
sage: C.count()
6
sage: [p for p in C]
[[2, 0, 0], [1, 1, 0], [1, 0, 1], [0, 2, 0], [0, 1, 1], [0, 0, 2]]
 }}}
 Here's the list of all compositions of 4:
 {{{
sage: list(IntegerListsLex(4, min_part = 1))
[[4], [3, 1], [2, 2], [2, 1, 1], [1, 3], [1, 2, 1], [1, 1, 2], [1, 1, 1, 1]]
 }}}


 * Cleanup of crystal code (Anne Schilling, Nicolas M. Thiery) -- Cartan type is now implemented as the method {{{cartan_type}}}, rather than an attribute as was previously the case.


 * Deprecate the function {{{RestrictedPartitions()}}} (Dan Drake) -- The function {{{RestrictedPartitions()}}} in {{{sage/combinat/partition.py}}} is now deprecated and will be removed in a future release. Users are advised to instead consider the function {{{Partitions()}}} with the {{{parts_in}}} keyword, which is functionally equivalent to {{{RestrictedPartitions()}}} but is more memory and time efficient. The timing improvement in {{{Partitions()}}} is up to 5x faster than {{{RestrictedPartitions()}}}. The following memory and timing statistics are produced using the machine sage.math:
 {{{
# BEFORE

sage: get_memory_usage()
721.26171875
sage: ps = RestrictedPartitions(100, ([1,6..100] + [4,9..100]))
sage: %time sum(1 for p in ps)
CPU times: user 27.26 s, sys: 1.06 s, total: 28.32 s
Wall time: 28.99 s
74040
sage: get_memory_usage()
1807.03515625

sage: get_memory_usage()
721.265625
sage: ps = RestrictedPartitions(3000, [10,50,100,500,1000])
sage: %time sum(1 for p in ps)
CPU times: user 5.60 s, sys: 0.21 s, total: 5.81 s
Wall time: 5.95 s
3506
sage: get_memory_usage()
962.54296875


# AFTER

sage: get_memory_usage()
719.3984375
sage: ps = Partitions(100, parts_in=([1,6..100] + [4,9..100]))
sage: %time sum(1 for p in ps)
CPU times: user 5.09 s, sys: 0.01 s, total: 5.10 s
Wall time: 5.10 s
74040
sage: get_memory_usage()
719.3984375

sage: get_memory_usage()
719.3984375
sage: ps = Partitions(3000, parts_in=[10,50,100,500,1000])
sage: %time sum(1 for p in ps)
CPU times: user 1.12 s, sys: 0.01 s, total: 1.13 s
Wall time: 1.13 s
3506
sage: get_memory_usage()
719.3984375
 }}}


 * Speed-up the {{{weyl_characters.py}}} module (Mike Hansen, Daniel Bump, Michael Abshoff) -- The timing efficiency is between 4x to 10x, depending on the operations involved. Here are some timing statistics produced using the machine sage.math:
 {{{
# BEFORE
sage: R = WeylCharacterRing(['B',3], prefix = "R")
sage: %time r = R(1,1,0)
CPU times: user 0.14 s, sys: 0.00 s, total: 0.14 s
Wall time: 0.14 s
sage:
sage: R = WeylCharacterRing(['B',3], prefix = "R")
sage: %time [R(w) for w in R.lattice().fundamental_weights()]
CPU times: user 0.25 s, sys: 0.00 s, total: 0.25 s
Wall time: 0.25 s
[R(1,0,0), R(1,1,0), R(1/2,1/2,1/2)]
sage:
sage: A2 = WeylCharacterRing(['A',2])
sage: %time [A2(0,0,0)+A2(2,1,0), A2(2,1,0)+A2(0,0,0), - A2(0,0,0)+2*A2(0,0,0),
-2*A2(0,0,0)+A2(0,0,0), -A2(2,1,0)+2*A2(2,1,0)-A2(2,1,0)]
CPU times: user 0.18 s, sys: 0.00 s, total: 0.18 s
Wall time: 0.19 s
[A2(0,0,0) + A2(2,1,0), A2(0,0,0) + A2(2,1,0), A2(0,0,0), -A2(0,0,0), 0]
sage:
sage: A2 = WeylCharacterRing(['A',2])
sage: %timeit [-x for x in [A2(0,0,0), 2*A2(0,0,0), -A2(0,0,0), -2*A2(0,0,0)]]
10 loops, best of 3: 20 ms per loop
sage:
sage: A2 = WeylCharacterRing(['A',2])
sage: chi = A2(0,0,0)+2*A2(1,0,0)+3*A2(2,0,0)
sage: mu = 3*A2(0,0,0)+2*A2(1,0,0)+A2(2,0,0)
sage: %timeit chi - mu
100 loops, best of 3: 8.16 ms per loop
sage:
sage: A2 = WeylCharacterRing(['A',2])
sage: chi = A2(1,0,0)
sage: %time [chi^k for k in range(6)]
CPU times: user 1.05 s, sys: 0.02 s, total: 1.07 s
Wall time: 1.07 s

[A2(0,0,0),
 A2(1,0,0),
 A2(1,1,0) + A2(2,0,0),
 A2(1,1,1) + 2*A2(2,1,0) + A2(3,0,0),
 3*A2(2,1,1) + 2*A2(2,2,0) + 3*A2(3,1,0) + A2(4,0,0),
 5*A2(2,2,1) + 6*A2(3,1,1) + 5*A2(3,2,0) + 4*A2(4,1,0) + A2(5,0,0)]


# AFTER

sage: R = WeylCharacterRing(['B',3], prefix = "R")
sage: %time r = R(1,1,0)
CPU times: user 0.03 s, sys: 0.00 s, total: 0.03 s
Wall time: 0.03 s
sage:
sage: R = WeylCharacterRing(['B',3], prefix = "R")
sage: %time [R(w) for w in R.lattice().fundamental_weights()]
CPU times: user 0.05 s, sys: 0.00 s, total: 0.05 s
Wall time: 0.05 s
[R(1,0,0), R(1,1,0), R(1/2,1/2,1/2)]
sage:
sage: A2 = WeylCharacterRing(['A',2])
sage: %time [A2(0,0,0)+A2(2,1,0), A2(2,1,0)+A2(0,0,0), - A2(0,0,0)+2*A2(0,0,0), -2*A2(0,0,0)+A2(0,0,0), -A2(2,1,0)+2*A2(2,1,0)-A2(2,1,0)]
CPU times: user 0.04 s, sys: 0.00 s, total: 0.04 s
Wall time: 0.04 s
[A2(0,0,0) + A2(2,1,0), A2(0,0,0) + A2(2,1,0), A2(0,0,0), -A2(0,0,0), 0]
sage:
sage: A2 = WeylCharacterRing(['A',2])
sage: %timeit [-x for x in [A2(0,0,0), 2*A2(0,0,0), -A2(0,0,0), -2*A2(0,0,0)]]
100 loops, best of 3: 3.33 ms per loop
sage:
sage: A2 = WeylCharacterRing(['A',2])
sage: chi = A2(0,0,0)+2*A2(1,0,0)+3*A2(2,0,0)
sage: mu = 3*A2(0,0,0)+2*A2(1,0,0)+A2(2,0,0)
sage: %timeit chi - mu
1000 loops, best of 3: 771 µs per loop
sage:
sage: A2 = WeylCharacterRing(['A',2])
sage: chi = A2(1,0,0)
sage: %time [chi^k for k in range(6)]
CPU times: user 0.20 s, sys: 0.00 s, total: 0.20 s
Wall time: 0.20 s

[A2(0,0,0),
 A2(1,0,0),
 A2(1,1,0) + A2(2,0,0),
 A2(1,1,1) + 2*A2(2,1,0) + A2(3,0,0),
 3*A2(2,1,1) + 2*A2(2,2,0) + 3*A2(3,1,0) + A2(4,0,0),
 5*A2(2,2,1) + 6*A2(3,1,1) + 5*A2(3,2,0) + 4*A2(4,1,0) + A2(5,0,0)]
 }}}


== Commutative Algebra ==


 * New function {{{weil_restriction()}}} on multivariate ideals (Martin Albrecht) -- The new function {{{weil_restriction()}}} computes the [[http://en.wikipedia.org/wiki/Weil_restriction|Weil restriction]] of a multivariate ideal over some extension field. A Weil restriction is also known as a restriction of scalars. Here's an example on computing a Weil restriction:
 {{{
sage: k.<a> = GF(2^2)
sage: P.<x,y> = PolynomialRing(k, 2)
sage: I = Ideal([x*y + 1, a*x + 1])
sage: I.variety()
[{y: a, x: a + 1}]
sage: J = I.weil_restriction()
sage: J
Ideal (x1*y0 + x0*y1 + x1*y1, x0*y0 + x1*y1 + 1, x0 + x1, x1 + 1) of
Multivariate Polynomial Ring in x0, x1, y0, y1 over Finite Field of size 2
 }}}


 * FIXME: summarize #5146


 * FIXME: summarize #5353


 * FIXME: summarize #3812


== Distribution ==


== Doctest ==


 * FIXME: summarize #5318


== Documentation ==


== Geometry ==

 * Improved enumeration of vertices and 0-dimensional faces of LatticePolytope's. There was an inconsistency between indicies of vertices, i.e. columns of the .vertices() matrix, and indicies of 0-dimensional faces, i.e. objects returned by .faces(dim=0). E.g. the 5-th 0-dimensional face could be generated by the 7-th vertex etc. Now the i-th 0-dimensional face is generated by the i-th vertex. (The reason for the old behaviour was the output of the underlying software package PALP, now there is extra sorting.)

== Graph Theory ==


 * FIXME: summarize #5623


== Graphics ==


 * FIXME: summarize #5606

 * FIXME: summarize #5450


== Group Theory ==


 * Speed-up in comparing elements of a permutation group (Robert Bradshaw, John H. Palmieri, Rob Beezer) -- For elements of a permutation group, comparison between those elements is now up to 13x faster. On Mac OS X 10.4 with Intel Core 2 duo running at 2.33 GHz, one has the following improvement in timing statistics:
 {{{
# BEFORE
sage: a = SymmetricGroup(20).random_element()
sage: b = SymmetricGroup(10).random_element()
sage: timeit("a == b")
625 loops, best of 3: 3.19 µs per loop


# AFTER
sage: a = SymmetricGroup(20).random_element()
sage: b = SymmetricGroup(10).random_element()
sage: time v = [a == b for _ in xrange(2000)]
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s
sage: timeit("a == b")
625 loops, best of 3: 240 ns per loop
 }}}


 * FIXME: summarize #5264


== Interfaces ==


== Linear Algebra ==


 * Deprecate the function {{{invert()}}} (John H. Palmieri) -- The function {{{invert()}}} for calculating the inverse of a dense matrix with rational entries is now deprecated. Instead, users are now advised to use the function {{{inverse()}}}. Here's an example of using the function {{{inverse()}}}:
 {{{
sage: a = matrix(QQ, 2, [1, 5, 17, 3])
sage: a.inverse()
[-3/82 5/82]
[17/82 -1/82]
 }}}


 * Speed-up in calculating determinants of matrices (John H. Palmieri, William Stein) -- For matrices over {{{Z/nZ}}} with {{{n}}} composite, calculating their determinants is now up to 1500x faster. On Debian 5.0 Lenny with kernel 2.6.24-1-686, an Intel(R) Celeron(R) 2.00GHz CPU with 1.0GB of RAM, one has the following timing statistics:
 {{{
# BEFORE
sage: time random_matrix(Integers(26), 10).determinant()
CPU times: user 15.52 s, sys: 0.02 s, total: 15.54 s
Wall time: 15.54 s
13
sage: time random_matrix(Integers(256), 10).determinant()
CPU times: user 15.38 s, sys: 0.00 s, total: 15.38 s
Wall time: 15.38 s
144


# AFTER
sage: time random_matrix(Integers(26), 10).determinant()
CPU times: user 0.01 s, sys: 0.00 s, total: 0.01 s
Wall time: 0.01 s
23
sage: time random_matrix(Integers(256), 10).determinant()
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s
 }}}


 * FIXME: summarize #5715


== Miscellaneous ==


 * FIXME: summarize #5638

 * FIXME: summarize #5386


== Modular Forms ==


 * FIXME: summarize #5520

 * FIXME: summarize #5648

 * FIXME: summarize #5180


== Notebook ==


FIXME: A number of tickets related to UTF-8 text got merged and should definitely be mentioned! #4547, #5211; #2896 and #1477 got fixed by those tickets. There's also #5564, which may not get merged for 3.4.1 but should get in soon; it pulls together a whole bunch of UTF-8 fixes and improvements.


 * FIXME: summarize #5681


== Number Theory ==


 * FIXME: summarize #5518

 * FIXME: summarize #5508

 * FIXME: summarize #793

 * FIXME: summarize #4667

 * FIXME: summarize #5159

 * FIXME: summarize #4990

 * FIXME: summarize #3081

 * FIXME: summarize #4724

 * FIXME: summarize #5673


== Numerical ==


== Packages ==


 * FIXME: summarize #4987

 * FIXME: summarize #4881

 * FIXME: summarize #4880

 * FIXME: summarize #4876

 * FIXME: summarize #5672

 * FIXME: summarize #5240

 * FIXME: summarize #5738

 * FIXME: summarize #5696

 * FIXME: summarize #4987

 * FIXME: summarize #5697

 * FIXME: summarize #5823


== Quadratic Forms ==


== Symbolics ==

 * FIXME: summarize #5737


== User Interface ==


== Website / Wiki ==
moved to https://github.com/sagemath/sage/releases

moved to https://github.com/sagemath/sage/releases

ReleaseTours/sage-3.4.1 (last edited 2024-08-19 01:43:28 by mkoeppe)