Path: csiph.com!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.lang.c++ Subject: Re: Sieve of Erastosthenes optimized to the max Date: Sun, 02 Jun 2024 19:50:36 -0700 Organization: A noiseless patient Spider Lines: 24 Message-ID: <86h6eaoi2r.fsf@linuxsc.com> References: <86r0duwqgg.fsf@linuxsc.com> <86o78mpnlf.fsf@linuxsc.com> <86ttibod7n.fsf@linuxsc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Date: Mon, 03 Jun 2024 04:50:36 +0200 (CEST) Injection-Info: dont-email.me; posting-host="df68cad4d9500866e5e56f3de5ab6749"; logging-data="3920212"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/uNVWID3uL2tk45bVX9KfNd64gMDVzlo0=" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:A9k8b60jsRVPqtAmdkBL3OPb7x0= sha1:lkGJZeC3mxEmJqEPPrTOrCkbWpI= Xref: csiph.com comp.lang.c++:119457 Tim Rentsch writes: > Pseudocode now looks something like this: > > for each index i in the table : > for each bit in table[i] : > if that bit has been marked composite : continue > // we have found the next prime > for each index j > i in the table : > for each bit in table[j] : > if that bit has beem marked composite : continue > // we have found a multiplier m and .. > // need to mark as composite p*m > end > end > end > end Correction: that should be for each index j >= i in the table : Also I have left out some possible optimizations, in the interest of simplifying the explanation.