Re: linpack C source

[Toon Moene <toon at moene dot indiv dot nluug dot nl>]

>  If anyone needs the source, I've put it up for ftp at:
>
>  ftp://shell14.ba.best.com/pub.t/tm2/linpackc.c

The interesting part of the source, which you unfortunately didn't  
copy in your previous message, is this:

                        y[i] = ((((((((((((((( (y[i])
                                + x[j-15]*m[ldm*(j-15)+i])
                                + x[j-14]*m[ldm*(j-14)+i])
                                + x[j-13]*m[ldm*(j-13)+i])
                                + x[j-12]*m[ldm*(j-12)+i])
                                + x[j-11]*m[ldm*(j-11)+i])
                                + x[j-10]*m[ldm*(j-10)+i])
                                + x[j- 9]*m[ldm*(j- 9)+i])
                                + x[j- 8]*m[ldm*(j- 8)+i])
                                + x[j- 7]*m[ldm*(j- 7)+i])
                                + x[j- 6]*m[ldm*(j- 6)+i])
                                + x[j- 5]*m[ldm*(j- 5)+i])
                                + x[j- 4]*m[ldm*(j- 4)+i])
                                + x[j- 3]*m[ldm*(j- 3)+i])
                                + x[j- 2]*m[ldm*(j- 2)+i])
                                + x[j- 1]*m[ldm*(j- 1)+i])
                                + x[j]   *m[ldm*j+i];

The problem here is the hand-unrolled loop (don't you love  
benchmarks :-().  Try the same with a simple loop and let egcs  
unroll it (because the loop is so small, it will probably unroll it  
4 times, which on a ix86 indeed loses, but it will be much better  
than the "original").

Cheers,
Toon.

PS:  I hope noone on this list thinks physicists write this sort of
     cruft for a living ...  I've better things to do with my time.