Timeline for How to Derive Tuples Without Replacement
Current License: CC BY-SA 3.0
19 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 16, 2020 at 9:23 | history | edited | CommunityBot | Commonmark migration | |
| Apr 13, 2017 at 12:55 | history | edited | CommunityBot | replaced http://mathematica.stackexchange.com/ with https://mathematica.stackexchange.com/ | |
| Jan 20, 2015 at 13:54 | history | edited | Mr.Wizard | CC BY-SA 3.0 | added 1091 characters in body |
| Feb 20, 2012 at 14:33 | comment | added | Sinistar | Worked after about 40 hours. I havent been able to look the out put over yet, because once I wanted to view the output, M! gobbled up all my memory and it has been regurgitating the dataset now for about 12 hours so far. Looks like it worked as desired, but I only had a snippet of results to look at. Maybe I need to figure out how to spit the output to a text file as it gathers results. | |
| Feb 17, 2012 at 20:15 | comment | added | Sinistar | @Mr.Wizard Very easy on memory! I started it a few minutes ago, I went ahead and threw all the monkeys and wrenches at your algorithm. I will let you know how long it took to run, but it doesnt look like it will be any faster, but has much less potential to crash the evaluation. I'm puzzled about 1 thing though, CPU is less 15% used, and less than 2GB of RAM. Where is the IO blocking at? The output should weigh in less than 10 million combinations. | |
| Feb 17, 2012 at 19:25 | comment | added | Sinistar | I will indeed! Thanks! And I do appreciate your help. The problem I am grappling with is hard enough for me and having to grapple with the intracacies of M! compounds the problem. I do love M! though, just a good bit different than anything I have worked with before. | |
| Feb 17, 2012 at 18:12 | comment | added | Mr.Wizard | @Sinistar please test my current code ant tell me if the result matches your expectation. | |
| Feb 17, 2012 at 18:12 | history | edited | Mr.Wizard | CC BY-SA 3.0 | deleted 50 characters in body |
| Feb 17, 2012 at 18:09 | comment | added | Mr.Wizard | @Sinistar if ordering doesn't matter I'll tweak my code a little. | |
| Feb 17, 2012 at 18:05 | history | edited | Mr.Wizard | CC BY-SA 3.0 | deleted 50 characters in body |
| Feb 17, 2012 at 18:03 | comment | added | Sinistar | It's an Urn Ball problem. Remove a ball, and don't put it back in the choices (i.e. 'select without replacement') and ordering doesn't matter, Red, Blue, Black is the same as Blue, Red, Black. So with the list version, 1,2,4 is identical in this consideration to 4,2,1 (and lexicographically those are undesireable in this application). | |
| Feb 17, 2012 at 17:41 | comment | added | Mr.Wizard | @kguler indeed I misread the question; what exactly is an "ordering repeat" ? | |
| Feb 17, 2012 at 17:37 | comment | added | kglr | Perhaps, I misunderstood the question, but for the example lists a and b your first function outputs a list that contains both {2, 3}, {2, 4}, {2, 6}, {3, 4}, {3, 6}, {4, 6} and their reversed versions. | |
| Feb 17, 2012 at 17:33 | history | edited | Mr.Wizard | CC BY-SA 3.0 | added 591 characters in body |
| Feb 17, 2012 at 17:21 | comment | added | Mr.Wizard | @Sinistar please see my update | |
| Feb 17, 2012 at 17:19 | history | edited | Mr.Wizard | CC BY-SA 3.0 | added 347 characters in body |
| Feb 17, 2012 at 17:17 | comment | added | Sinistar | Join @@ (Thread[{#, #, DeleteCases[cc, #]}] & /@ {aa, bb}) I tried this, expanding to three lists for a try, it keeps the 3rd list unique, but won't make the first two unique. I get almost the opposite! :) {1,1,4}, {2,2,8}, {3,3,12} etc. | |
| Feb 17, 2012 at 17:02 | comment | added | Sinistar | That seems to work great with two lists, given my simple example question. In my real problem I am actually working with 6 lists with up to 25+ items in each list (and the item count may not be equal). I will try and study your code and see if I can work it out. The little manipulators like #,&,/,@ kind of seem kind of confusing, probably cause just because I am not clear on what they do in all cases. Thanks for the help! | |
| Feb 17, 2012 at 16:50 | history | answered | Mr.Wizard | CC BY-SA 3.0 |