Re: FYI: optimizing certain matrix arithmetic

[Michael D Godfrey]

Just for the record, a comparison with the "other system"
model name    : AMD Athlon(tm) 64 X2 Dual Core Processor 4200+
stepping    : 2
cpu MHz        : 1000.000
cache size    : 512 KB
bogomips    : 2009.24

Other system:

>> matrix_upd
Elapsed time is 0.693973 seconds.
Elapsed time is 0.713473 seconds.
Elapsed time is 0.578210 seconds.
Elapsed time is 0.626382 seconds.
Elapsed time is 1.109518 seconds.
Elapsed time is 1.074281 seconds.
>> matrix_upd
Elapsed time is 0.672716 seconds.
Elapsed time is 0.589409 seconds.
Elapsed time is 0.586399 seconds.
Elapsed time is 0.588210 seconds.
Elapsed time is 0.917150 seconds.
Elapsed time is 0.965731 seconds.
>> matrix_upd
Elapsed time is 0.654106 seconds.
Elapsed time is 0.579242 seconds.
Elapsed time is 0.579452 seconds.
Elapsed time is 0.606396 seconds.
Elapsed time is 0.900270 seconds.
Elapsed time is 0.981272 seconds.
>>
================================
Octave:

octave:1> matrix_upd
Elapsed time is 3.63911 seconds.
Elapsed time is 3.60394 seconds.
Elapsed time is 3.28712 seconds.
Elapsed time is 3.68529 seconds.
Elapsed time is 1.00189 seconds.
Elapsed time is 1.05105 seconds.
octave:2> matrix_upd
Elapsed time is 3.59402 seconds.
Elapsed time is 3.68178 seconds.
Elapsed time is 3.41025 seconds.
Elapsed time is 3.81864 seconds.
Elapsed time is 0.995547 seconds.
Elapsed time is 1.0422 seconds.
octave:3> matrix_upd
Elapsed time is 3.67623 seconds.
Elapsed time is 3.61439 seconds.
Elapsed time is 3.27442 seconds.
Elapsed time is 3.69338 seconds.
Elapsed time is 0.959457 seconds.
Elapsed time is 0.994716 seconds.
octave:4>