Timeline for Find points whose pairwise distances approximate a given distance matrix
Current License: CC BY-SA 4.0
22 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| S Aug 27, 2019 at 14:00 | history | suggested | Misi | CC BY-SA 4.0 | Link corrected |
| Aug 27, 2019 at 7:32 | review | Suggested edits | |||
| S Aug 27, 2019 at 14:00 | |||||
| Jun 12, 2014 at 7:24 | history | bounty awarded | Stephan Kolassa | ||
| Jun 7, 2014 at 16:26 | history | edited | Eamon Nerbonne | CC BY-SA 3.0 | added 234 characters in body |
| Jun 7, 2014 at 16:24 | comment | added | Eamon Nerbonne | @StephanKolassa: I've also included a sample implementation now. Note that your example input is actually a nasty case because it violates the triangle inequality... | |
| Jun 7, 2014 at 16:09 | comment | added | Stephan Kolassa | @EamonNerbonne: sorry, my bad. I had misunderstood the definition of J. I worked through the PDF you linked, and everything is clear now. May I suggest that you edit your answer to include the link? And once again: thank you for your help! | |
| Jun 7, 2014 at 15:48 | history | edited | Eamon Nerbonne | CC BY-SA 3.0 | Added a simple implementation. |
| Jun 7, 2014 at 15:21 | comment | added | Eamon Nerbonne | JDJ will not have a zero diagonal when D has a zero diagonal - what's the reasoning there? I just implemented this to verify, and it works. I'll include the code in the answer. | |
| Jun 7, 2014 at 10:05 | vote | accept | Stephan Kolassa | ||
| Jun 7, 2014 at 10:05 | comment | added | Stephan Kolassa | There still seems to be something off. B=X^tX will have the squared lengths of the original vectors on the diagonal, but DD, as a distance matrix, will have a zero diagonal, so JDJ will also have a zero diagonal, so B can't be equal to JDJ. But you have definitely answered my question, given the Wikipedia entry and the pdf you linked to in your comment, so I'll go ahead and accept. Thanks a lot! | |
| Jun 6, 2014 at 15:57 | comment | added | Eamon Nerbonne | @StephanKolassa: that better? | |
| Jun 6, 2014 at 15:52 | history | edited | Eamon Nerbonne | CC BY-SA 3.0 | added 8 characters in body |
| Jun 6, 2014 at 15:25 | comment | added | Eamon Nerbonne | @StephanKolassa: pages 9-11 here give a good example: homepages.uni-tuebingen.de/florian.wickelmaier/pubs/…. I'll update my answer shortly with the missing step once I figure out how to intuitively explain it :-) | |
| Jun 6, 2014 at 15:14 | comment | added | Eamon Nerbonne | @StephanKolassa Oh right, I forgot the centering step, let me look that up again... | |
| Jun 6, 2014 at 14:59 | comment | added | Stephan Kolassa | This does look promising. However, I kind of get stuck at the distance matrix being the product of the transpose of the position matrix with itself. I can't get that to work for simple examples. Given that the crossproduct is not translation-invariant, while the distance certainly is, I am sure I am missing something. Could you perhaps elaborate a bit? | |
| Jun 6, 2014 at 14:20 | comment | added | Eamon Nerbonne | @michipili It happens to be exactly the problem I've encountered before, and a really nifty trick that turns out to be applicable more often than you might think :-) | |
| Jun 6, 2014 at 14:18 | history | edited | Eamon Nerbonne | CC BY-SA 3.0 | add example |
| Jun 6, 2014 at 14:16 | comment | added | Michaël Le Barbier | A very fair answer indeed! | |
| Jun 6, 2014 at 14:04 | review | First posts | |||
| Jun 6, 2014 at 14:37 | |||||
| Jun 6, 2014 at 14:03 | history | edited | Eamon Nerbonne | CC BY-SA 3.0 | added 659 characters in body |
| Jun 6, 2014 at 13:55 | history | edited | Eamon Nerbonne | CC BY-SA 3.0 | added 659 characters in body |
| Jun 6, 2014 at 13:46 | history | answered | Eamon Nerbonne | CC BY-SA 3.0 |