Initial- and boundary-value problems in Maxima.

Raymond Toy wrote:

x
>>
>> I don't understand the discrepancy between 50% of the time and
>> "negligible"
>> between  Michel and Ray;
>> since I have some interest (as does Ray) in making lisp numerical
>> programs run fast, I hope we can come to some agreement on this.
>>
>> Could be that sbcl did a better job of optimizing, especially if it's a
> 64-bit version because then the 32-bit integer Fortran quantities will fit
> nicely in a fixnum. Could also be a bug in cmucl's profiler.
> 
> Ray

My machine is a 32 bits machine. I have here, in another mail to you,
profiles with both cmucl and sbcl which are consistent between themselves
but not consistent with your profiles, so we can only agree to disagree.
These profiles were done with you new colnew-if which allows to see
directly the time spent in fsub and dfsub (basically 50 %): Note that dgesl
and dgefa are much slower in cmucl than in sbcl. As always the boundary
conditions gsub and dgsub are not relevant. This is because fsub and dfsub
are computed on all mesh points while the boundary conditions are computed
on 4 points only on this problem. And the number of mesh points rises up to
around 80, plus there are several Newton iterations.

cmucl
_____


Elapsed time,  82.20000000000002  seconds

      Consed |   Calls |   Secs | Sec/Call |  Bytes/C. | Name:
-----------------------------------------------------------------------
  307,865,672 |  52,284 | 19.871 |  0.00038 |     5,888 | FSUB
  205,306,464 |  52,124 | 14.742 |  0.00028 |     3,939 | COLNEW::DGESL
  349,802,776 |  23,178 | 14.567 |  0.00063 |    15,092 | DFSUB
  110,750,040 |   1,064 | 12.956 |  0.01218 |   104,088 | COLNEW::LSYSLV
   84,280,384 |   7,726 |  8.309 |  0.00108 |    10,909 | COLNEW::DGEFA
   16,853,120 |  23,178 |  3.257 |  0.00014 |       727 | COLNEW::VWBLOK
  143,175,200 |     101 |  2.900 |  0.02871 | 1,417,576 | $COLNEW_EXPERT
   14,118,080 |   2,524 |  1.140 |  0.00045 |     5,594 | GSUB
    9,041,576 |   1,288 |  0.575 |  0.00045 |     7,020 | DGSUB
-------------------------------------------------------------------
1,241,193,312 | 163,467 | 78.316 |          |           | Total


sbcl
_____

Elapsed time,  70.38500000000002  seconds


  seconds  |     gc     |     consed    |  calls  |  sec/call  |  name
-------------------------------------------------------------
    21.101 |      0.161 |   269,494,984 |  52,284 |   0.000404 | FSUB
    16.015 |      0.539 |   337,162,200 |  23,178 |   0.000691 | DFSUB
    10.203 |      0.587 |   557,970,888 |   1,064 |   0.009589 |
COLNEW::LSYSLV
    10.006 |      1.047 |   800,253,040 |  52,124 |   0.000192 |
COLNEW::DGESL
     4.073 |      0.402 |   317,906,360 |   7,726 |   0.000527 |
COLNEW::DGEFA
     3.503 |      0.358 |   222,979,672 |     101 |   0.034684 |
$COLNEW_EXPERT
     1.257 |      0.005 |    12,231,336 |  23,178 |   0.000054 |
COLNEW::VWBLOK
     0.869 |      0.052 |    10,649,800 |   2,524 |   0.000344 | GSUB
     0.334 |      0.000 |     4,102,240 |   1,288 |   0.000259 | DGSUB
-------------------------------------------------------------
    67.360 |      3.151 | 2,532,750,520 | 163,467 |            | Total






-- 
Michel Talon