> Please do, and let me and Niels know if it takes more than 45s. Your > test case takes 28s on my 3.3 GHz Sandy bridge system with our current > code. I'm a little disappointed the code doesn't beat the old code more > for small factorisations. So on my 2.1GHz i3-2310M, running over the range 452,930,477 to 472,882,027. old broken code = 14m old fixed code = 18m new code = 63s OK, this is about 60% slower than I would have expected. Our code at http://gmplib.org:8000/factoring/ should run at about 39s on your system. (I am using gcc 4.7.1.)
I haven't looked at the final version that went into codeutils, so I have no idea why it runs slower. A wild guess is that its actual input or tokenisation has been slowed down. For smallish numbers, such things can dominate over actually factoring the numbers. I think the current coreutils factor performance for smallish numbers might be sufficient. (Larger numbers than 2^100 need a bit too much time, but we are working on a fix.) -- Torbjörn
