Timeline for BSplineFunction derivatives wrong if using weights?
Current License: CC BY-SA 4.0
24 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 10, 2021 at 1:26 | comment | added | J. M.'s missing motivation♦ | I haven't tried, @ABCDEMMM. Do your own experiments, and bug Support if it still hasn't been fixed. Then they might get an idea of how in demand this is. | |
| Jun 6, 2021 at 22:06 | comment | added | ABCDEMMM | @J. M. can we now directly use second/third BSplineFunction derivatives in MMA 12.2`? | |
| Feb 4, 2020 at 13:56 | history | edited | J. M.'s missing motivation♦ |
edited tags
|
|
| Feb 3, 2020 at 19:03 | history | edited | Lukas Lang | CC BY-SA 4.0 |
edited body
|
| Sep 4, 2017 at 11:38 | history | edited | J. M.'s missing motivation♦ | CC BY-SA 3.0 |
deleted 2 characters in body
|
| Nov 19, 2016 at 13:57 | history | edited | user31159 | CC BY-SA 3.0 |
Updated bug banner.
|
| Mar 24, 2016 at 18:43 | history | edited | Silvia | CC BY-SA 3.0 |
deleted 2 characters in body
|
| Mar 20, 2016 at 7:29 | history | edited | xyz | CC BY-SA 3.0 |
added 64 characters in body
|
| Feb 20, 2016 at 11:57 | answer | added | xyz | timeline score: 8 | |
| Jan 23, 2016 at 13:12 | history | edited | xyz | CC BY-SA 3.0 |
added 40 characters in body
|
| Jul 11, 2015 at 21:14 | answer | added | J. M.'s missing motivation♦ | timeline score: 9 | |
| Jul 11, 2015 at 21:02 | history | edited | J. M.'s missing motivation♦ | CC BY-SA 3.0 |
edited body
|
| Jul 29, 2014 at 20:11 | answer | added | george2079 | timeline score: 6 | |
| Mar 28, 2014 at 10:47 | comment | added | user7987 | I did fill a bug report, and I had an anwser saying that yes, indeed it was a bug, and that it will be corrected in future releases. But not a word since. I actually finished my work with Splines using a BSplineFunction I redefined, but this was extremely unsatisfactory as it multiplied by at least 10 all my computing times. And I was completely unable to use it interactively, as was planned. | |
| Mar 21, 2014 at 18:37 | answer | added | gdir | timeline score: 5 | |
| Mar 21, 2014 at 9:40 | comment | added | gdir | user7987, did you get an answer to your bug report from Wolfram? I had just the same problem in Mathematica 9. Mathematica seems to compute the derivates of the BSplineFunction wrong, if weights are applied (different from 1.0). The function itself (0. derivate = compute curve point in 3D) is working as desired and computes the right coordinates even if the weigths are different from 1.0. But the derivates are only correct, if all weights are 1.0. Edit: I just tried to compute the derivates numerically with ND. This leads to correct results, while using D leads to incorrect values. | |
| Aug 21, 2013 at 13:39 | vote | accept | user7987 | ||
| Aug 20, 2013 at 22:45 | answer | added | Dr. belisarius | timeline score: 11 | |
| Aug 20, 2013 at 21:11 | history | tweeted | twitter.com/#!/StackMma/status/369929606134267904 | ||
| Aug 20, 2013 at 18:47 | comment | added | user7987 | I mean I redefined everything in my way: picewise polynomes for the B-Spline basis functions, rationnal polygones to have the Nurbs basis, and then the curve as the somme of basis*control points. The curve defined this way is perfectly equal to the curve defined by Mathematica, but their derivatives are not equal. | |
| Aug 20, 2013 at 18:12 | comment | added | Dr. belisarius | What do you mean by "(computed by redefining all the NURBS functions from the beginning)"? | |
| Aug 20, 2013 at 17:06 | history | edited | Dr. belisarius |
edited tags
|
|
| Aug 20, 2013 at 16:43 | history | edited | rcollyer | CC BY-SA 3.0 |
grammar; added link to NURBS
|
| Aug 20, 2013 at 16:17 | history | asked | user7987 | CC BY-SA 3.0 |