#5930: switch from maxima to pynac for core symbolic manipulation system
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Reporter: was | Owner: tbd
Type: enhancement | Status: new
Priority: blocker | Milestone: sage-4.0
Component: symbolics | Keywords:
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Comment(by was):
There is a sequence of *serious* speed regressions that I think Burcin
caused by changes to the pynac spkg:
IN SAGE-3.2 we get OK timings for this benchmarks. They aren't great, but
I can live with them, since it is"only" 57 times slower than Singular:
{{{
sage: var('x,y,z', ns=1); f = (x+y+z)^6;
sage: timeit('(f*(f+1)).expand()')
125 loops, best of 3: 3.25 ms per loop
}}}
In Singular:
{{{
sage: R.<x,y,z> = QQ[]
sage: timeit('g=(x+y+z)^6*((x+y+z)^6+1)')
625 loops, best of 3: 56.3 µs per loop
sage: 3250/56.3
57.7264653641208
}}}
It's hard to tell, but Mathematica seems to take about 1.7ms, which is
comparable to the above:
{{{
sage: timeit("s=mathematica('Expand[(x+y+z)^6*((x+y+z)^6+1)]')")
125 loops, best of 3: 1.81 ms per loop
sage: timeit("s=mathematica('2+3')")
625 loops, best of 3: 125 µs per loop
}}}
Maxima via Sage takes about 61 ms, since I guess (c)lisp is slow, etc.:
{{{
sage: timeit("s=maxima('expand((x+y+z)^6*((x+y+z)^6+1))')")
5 loops, best of 3: 61.8 ms per loop
}}}
First there was a MAJOR unacceptable speed regression going to sage-3.3
(this is probably all caused by the pynac spkg). The timing jumped all
the way to 42ms, so now it's almost as bad as Maxima:
{{{
sage: var('x,y,z', ns=1); f = (x+y+z)^6
(x, y, z)
sage: timeit('(f*(f+1)).expand()')
5 loops, best of 3: 42.1 ms per loop
}}}
In fact, directly in sage-3.2 with old Maxima symbolics:
{{{
sage: var('x,y,z', ns=0); f = (x+y+z)^6
sage: timeit('(f*(f+1)).expand()')
5 loops, best of 3: 106 ms per loop
}}}
IN SAGE-3.4.2 with new symbolics:
{{{
sage: var('x,y,z', ns=1); f = (x+y+z)^6
(x, y, z)
sage: timeit('(f*(f+1)).expand()')
5 loops, best of 3: 206 ms per loop
}}}
This may be due to a change in the pynac layer, where it is calling out to
Python for some reason, even though it shouldn't need to. 206ms is
really unacceptable. It's much slower than Maxima itself, it's 63 times
slower than Pynac *was* just a few months ago, and it's 367 times slower
than Singular.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5930#comment:4>
Sage <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of
Reinventing the Wheel
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