Maxima Lapack is very slow: 7 seconds versus 0.002 seconds in Julia.



Raymond Toy wrote:
> On 5/5/12 7:36 AM, Manuel Pedrinero rossetil wrote:
>> Recently Raimond Toy asked about what capabilities are lacking in
>> maxima, numeric computations in linear algebra seems to be very slow
>>
> That's not a lack of capability, but rather a quality of implementation
> issue.
>>
>>  This is an example in gcl using lapack
>>
>> (%i1) load(lapack);
>> /share/lapack/binary-gcl/dgemm.o
>> (%o1)          /usr/share/maxima/5.24.0/share/lapack/lapack.mac
>> (%i2) h[i,j]:= 1/(i+j);
>>                                            1
>> (%o2)                           h     := -----
>>                                  i, j    i + j
>> (%i3) m : genmatrix(h,50,50)$
>>
>> (%i4) showtime : true;
>> Evaluation took 0.0000 seconds (0.0000 elapsed)
>> (%o4)                                true
>> (%i5) [one,two,three] : dgeev(m)$
>> Evaluation took 7.3200 seconds (7.4000 elapsed)
>>
>
> What kind of machine did you run this on?  On my machine, this took .04
> sec (using cmucl).
>

My machine is like yours. On this macbook air laptop, with maxima compiled
from sbcl, i get:
(%i5) [one,two,three] : dgeev(m)$
Evaluation took 0.0250 seconds (0.0370 elapsed) using 2.128 MB.

This is not that bad compared to the reported result from julia.


-- 
Michel Talon