Ticket #6016 (closed: wontfix)
Implement mutliple step fit in LeBailFit and more
| Reported by: | Wenduo Zhou | Owned by: | Wenduo Zhou |
|---|---|---|---|
| Priority: | major | Milestone: | Release 2.4 |
| Component: | Mantid | Keywords: | |
| Cc: | Blocked By: | ||
| Blocking: | Tester: | Nick Draper |
Description (last modified by Wenduo Zhou) (diff) ¶
Implement multiple step fit in LeBailFit to increase the computation efficiency. If in one step, the minimizer uses differential of the function and the covariance between any 2 parameters, do the fitting again by using 'simplex' as the minimizer.
Add property "DampingFactor" if the user specifies the minimizer as "Damping".
Change History
comment:2 Changed 8 years ago by Wenduo Zhou
- Status changed from new to accepted
- Description modified (diff)
- Summary changed from Implement mutliple step fit in LeBailFit to Implement mutliple step fit in LeBailFit and more
comment:3 Changed 8 years ago by Wenduo Zhou
Use numerical derivative. Refs #6016.
Changeset: 3fe0fc3b82ff4a95098d46d9d9fc8ae1dc225ae6
comment:4 Changed 8 years ago by Wenduo Zhou
More choice to set peak height explicitly. Refs #6016.
Changeset: 0a8ac0aacfe4951ca62cc2ac9ed53825e1ed6a91
comment:5 Changed 8 years ago by Wenduo Zhou
Fix the build. Refs #6016.
Changeset: ac859c3e83a4f70cf02afd21eddfe2f392c3279e
comment:6 Changed 8 years ago by Wenduo Zhou
Use numerical derivative. Refs #6016.
Changeset: 3fe0fc3b82ff4a95098d46d9d9fc8ae1dc225ae6
comment:7 Changed 8 years ago by Wenduo Zhou
More choice to set peak height explicitly. Refs #6016.
Changeset: 0a8ac0aacfe4951ca62cc2ac9ed53825e1ed6a91
comment:8 Changed 8 years ago by Wenduo Zhou
Fix the build. Refs #6016.
Changeset: ac859c3e83a4f70cf02afd21eddfe2f392c3279e
comment:9 Changed 8 years ago by Wenduo Zhou
- Status changed from accepted to verify
- Resolution set to wontfix
The peak function (thermal neutron back to back exponential convoluted with pseudo-voigt) has parameters strongly correlated. In real application, fitting with regular minimizer, such as Simplex and Levenberg-Marquardt, is very unstable. Alternatively, the Monte Carlo algorithm is robust and able to obtain a good result. Therefore, the effort on doing Le Bail fit with multiple step fit with regular minimizer is given up.
comment:10 Changed 8 years ago by Nick Draper
- Status changed from verify to verifying
- Tester set to Nick Draper
work continued in #6019
comment:12 Changed 5 years ago by Stuart Campbell
This ticket has been transferred to github issue 6862
