#5084: speed regression in number of partitons
---------------------------+------------------------------------------------
Reporter: robertwb | Owner: mhansen
Type: defect | Status: new
Priority: major | Milestone: sage-3.4.1
Component: combinatorics | Resolution:
Keywords: |
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Changes (by robertwb):
* owner: tbd => mhansen
* component: algebra => combinatorics
* milestone: => sage-3.4.1
Comment:
This is due to #3762. It might be nice to either (1) detect whether or not
quaddouble is available (e.g. if it's on the system or an optional
installed spkg) and turn on the macro to use it (2) make the mpfr version
faster. Some timings
{{{
%cython
#clang c++
from sage.libs.mpfr cimport *
from sage.rings.real_rqdf cimport *
def test_mpfr(N, bits=212):
cdef mpfr_t a, b
mpfr_init2(a, bits)
mpfr_init2(b, bits)
mpfr_random(a)
mpfr_random(b)
cdef int i
for i from 0 <= i < N:
mpfr_add(a, a, b, GMP_RNDN)
mpfr_mul(a, a, b, GMP_RNDN)
mpfr_clear(a)
mpfr_clear(b)
def test_qd(N):
cdef double a[4]
cdef double b[4]
cdef int i
c_qd_rand(a)
c_qd_rand(b)
for i from 0 <= i < N:
c_qd_add(a, a, b)
c_qd_mul(a, a, b)
}}}
and
{{{
sage: time test_mpfr(10^6, 212)
CPU time: 0.34 s, Wall time: 0.35 s
sage: time test_mpfr(10^6, 150)
CPU time: 0.22 s, Wall time: 0.23 s
sage: time test_qd(10^6)
CPU time: 0.25 s, Wall time: 0.26 s
}}}
(OS X 32-bit)
So there might be hope. Also, the constants calculated up front are used
to full (1000s of bits) precision throughout, which can slow things down
in some cases.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5084#comment:1>
Sage <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of
Reinventing the Wheel
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