On 2009-Apr-07 21:49:12 -0700, William Stein wst...@gmail.com wrote:
On Tue, Apr 7, 2009 at 9:24 PM, Bill Hart goodwillh...@googlemail.com wrote:
The reason it runs slow is a.factor() is bizarrely slow in Sage. It's
like a factor of 50 times slower than Pari.
There are some differences:
(1)
On Apr 9, 2:03 pm, Peter Jeremy peterjer...@optushome.com.au wrote:
On 2009-Apr-07 21:49:12 -0700, William Stein wst...@gmail.com wrote:
On Tue, Apr 7, 2009 at 9:24 PM, Bill Hart goodwillh...@googlemail.com
wrote:
The reason it runs slow is a.factor() is bizarrely slow in Sage. It's
On Apr 9, 2:11 pm, mabshoff mabsh...@googlemail.com wrote:
On Apr 9, 2:03 pm, Peter Jeremy peterjer...@optushome.com.au wrote:
SNIP
The primality test for pari is known to be lead to false results up to
10^14 or so (FLINT's is up to 10^16 IIRC what Bill told me a couple
days ago).
Opps,
Feeding the factors to Sage's factor command to check they are prime
is precisely what proof=true is all about. Testing primality in a
proven way, for numbers bigger than 10^16 is still very slow as there
is no really good algorithm known for it. I have some code written by
a student of mine
Yeah, the divisors function otherwise kicks proverbial:
Here in Sage (excuse my rubbish python):
def random(n):
a = ZZ.random_element(n)
return a
def z_divisors_test(m):
for j in range(0, m) :
n = random(10)
z = 1
c = 1
for i in range(0, n):
I mean half the memory that Sage uses, not half the memory of the
machine.
Bill.
On 8 Apr, 09:21, Bill Hart goodwillh...@googlemail.com wrote:
Yeah, the divisors function otherwise kicks proverbial:
Here in Sage (excuse my rubbish python):
def random(n):
a = ZZ.random_element(n)
On Tue, Apr 7, 2009 at 9:24 PM, Bill Hart goodwillh...@googlemail.com wrote:
The reason it runs slow is a.factor() is bizarrely slow in Sage. It's
like a factor of 50 times slower than Pari.
There are some differences:
(1) pari's factor is *not* provably correct, but Sage's is. [That
said,
On Apr 7, 2009, at 9:49 PM, William Stein wrote:
On Tue, Apr 7, 2009 at 9:24 PM, Bill Hart
goodwillh...@googlemail.com wrote:
The reason it runs slow is a.factor() is bizarrely slow in Sage. It's
like a factor of 50 times slower than Pari.
There are some differences:
(1) pari's
William didn't mention the context of this, which is that for small
integers most of the time taken by the divisors method in ZZ is taken
up with factoring. It seems much more likely people will use small
numbers as inputs to this, so this is a shame, given the amount of
work that (I hear) went
On Apr 7, 2009, at 10:26 PM, Bill Hart wrote:
William didn't mention the context of this, which is that for small
integers most of the time taken by the divisors method in ZZ is taken
up with factoring. It seems much more likely people will use small
numbers as inputs to this, so this is a
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