From BRYAN@wvnvm.wvnet.edu Wed Aug 10 08:38:50 1994 Return-Path: Received: from WVNVM.WVNET.EDU by life.ai.mit.edu (4.1/AI-4.10) for /com/archive/cube-lovers id AA15904; Wed, 10 Aug 94 08:38:50 EDT Message-Id: <9408101238.AA15904@life.ai.mit.edu> Received: from WVNVM.WVNET.EDU by WVNVM.WVNET.EDU (IBM VM SMTP V2R2) with BSMTP id 1777; Tue, 09 Aug 94 23:18:07 EDT Received: from WVNVM.WVNET.EDU (NJE origin BRYAN@WVNVM) by WVNVM.WVNET.EDU (LMail V1.2a/1.8a) with BSMTP id 0972; Tue, 9 Aug 1994 23:18:07 -0400 X-Acknowledge-To: Date: Tue, 9 Aug 1994 23:18:06 EDT From: "Jerry Bryan" To: Subject: Re: < U, R> Group In-Reply-To: Message of 08/09/94 at 01:48:00 from mark.longridge@canrem.com On 08/09/94 at 01:48:00 mark.longridge@canrem.com said: > I leave it to Jerry or Dan to check my results. I checked up to 2 >moves deep by hand and verified 10 different positions. What I don't >understand is how Jerry manages to look at so many cube positions: >On full 3x3x3 cube, 7 100,803,036 13.231 (new) > Using 10 bytes to store a single cube position would still >need over 1 billion bytes, or am I missing something? Well, when I deal with the big problems I want to solve to the bitter end, I use the M-conjugate and centerless cube tricks I have described at much too great length in the past. This one is a quick and dirty program using no conjugate tricks. The only real "trick" is that I externalize the data. I decided long ago that the problems I wanted to solve were too big to keep in memory. Hence, I keep everything in simple (but large) flat files and sort and merge the files like crazy. In this quick and dirty program, the cube itself is 13 bytes and the level is 1 byte, for a total of 14 bytes per cube. I guess that makes the file size about 1.4 gigabytes (10^9). I am leery of using the word "billion" on E-mail forums because E-mail is international and "billion" means 10^12 in some countries. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Robert G. Bryan (Jerry Bryan) (304) 293-5192 Associate Director, WVNET (304) 293-5540 fax 837 Chestnut Ridge Road BRYAN@WVNVM Morgantown, WV 26505 BRYAN@WVNVM.WVNET.EDU If you don't have time to do it right today, what makes you think you are going to have time to do it over again tomorrow?