Timeline for Strange outcome when performing nonlinear least squares fit to a power law
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 13, 2013 at 1:52 | history | edited | Glen_b | CC BY-SA 3.0 |
added 4 characters in body
|
| Jun 13, 2013 at 1:50 | comment | added | Glen_b | Ah, so it was the convergence criteria - sometimes, especially when the errors are tiny, the usual defaults don't work well. | |
| Jun 13, 2013 at 1:16 | vote | accept | Fixed Point | ||
| Jun 13, 2013 at 1:15 | comment | added | Fixed Point | I did try using the log-log linear results as my starting point and the same thing would happen. $b$ would just stay fixed at 7.57. It turns out that the default TolFun (Termination tolerance used on stopping conditions involving the function (model) value) and TolX (Termination tolerance used on stopping conditions involving the coefficients) were both 1e-6 which is apparently too high. I changed both to 1e-16 and now I am getting identical answers to NLS in R. Works wonderfully, many thanks! | |
| Jun 13, 2013 at 0:45 | history | edited | Glen_b | CC BY-SA 3.0 |
added 91 characters in body
|
| Jun 13, 2013 at 0:36 | history | edited | Glen_b | CC BY-SA 3.0 |
added 6 characters in body
|
| Jun 13, 2013 at 0:24 | history | edited | Glen_b | CC BY-SA 3.0 |
added 6 characters in body
|
| Jun 13, 2013 at 0:17 | history | edited | Glen_b | CC BY-SA 3.0 |
added 66 characters in body
|
| Jun 13, 2013 at 0:10 | history | answered | Glen_b | CC BY-SA 3.0 |