mpz_addmul_ui with ui = 1
mathimagics at yahoo.co.uk
Wed Jan 28 13:31:45 CET 2009
I have a loop that spends 99+% of its time executing these two statements:
mpz_addmul_ui(BB, B, a);
mpz_swap (B, BB);
To my surprise, it runs 25% faster if I replace it with:
if (a==1) mpz_add (BB, B, BB);
else mpz_addmul_ui(BB, B, a);
It's an RCF (regular continued-fraction) algorithm, so a=1 about 41.5% of the time.
No big deal, but perhaps in future revs mpz_addmul_ui and its sister function might auto-detect this case and reroute the call?
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