lmfit-py

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This group is intended for questions and discussion about the use of and design of the lmfit python library for optimization and curve-fitting. Any topic related to curve-fitting and Python is acceptable.

If you are posting a question about lmfit not working for you as you would expect, please include in your post:

a minimal and complete example. Please see https://stackoverflow.com/help/mcve for more details.
the fit report from lmfit, if you have one.
If an error occurs, include the full traceback.
It's OK to post an image of data and fit, but if you are including code or output, this must be in plain text. Do not post an image of text.

We expect that users of lmfit are familiar with Python and numpy and are smart people who know how to ask questions in a way that can be answered. If you are asking a question about why something "didn't work" or didn't give results you expect, we expect you to explain what you did, what you expected, and what you got. This usually means posting a minimal example that shows the problem.

0 selected

NovicePython, … Matt Newville6

Jun 16

lmfit setup for multiple curve fits

On Sat, Jun 15, 2024 at 1:01 PM NovicePython <kmu.s...@gmail.com> wrote: Let's take

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lmfit setup for multiple curve fits

On Sat, Jun 15, 2024 at 1:01 PM NovicePython <kmu.s...@gmail.com> wrote: Let's take

Jun 16

Vasco Cossa, … sam mahdi5

Jun 11

Power law fit - reduced chi squared and uncertainty on the slope

Thank you Sam, that really helps On Mon, Jun 10, 2024, 11:05 PM sam mahdi <sammah...@gmail.com

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Power law fit - reduced chi squared and uncertainty on the slope

Thank you Sam, that really helps On Mon, Jun 10, 2024, 11:05 PM sam mahdi <sammah...@gmail.com

Jun 11

melika moradi, … Laurence Lurio3

Jun 8

Fit a 2d model with multiple peaks

I can venture a few suggestions: 1. If your initial values for the peak positions are not close ,

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Fit a 2d model with multiple peaks

I can venture a few suggestions: 1. If your initial values for the peak positions are not close ,

Jun 8

Kima wari, Matt Newville2

May 29

easiest way to include square brackets in a parameter's name

> KeyError: "'binwidth[s]' is not a valid Parameters name" That is the correct

unread,

easiest way to include square brackets in a parameter's name

> KeyError: "'binwidth[s]' is not a valid Parameters name" That is the correct

May 29

Timothy Anderson, Matt Newville3

Apr 26

f(a) and f(b) must have different signs

I think that is signaling that `conf_interval()` call to `scipy.optimize.root_scalar` cannot find the

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f(a) and f(b) must have different signs

I think that is signaling that `conf_interval()` call to `scipy.optimize.root_scalar` cannot find the

Apr 26

ethan koren, … Laurence Lurio5

Apr 23

lmfit.eval() producing wrong values of my model functions

Yes that was the problem! Thank you very much. It is all working now :) On Wed, Apr 24, 2024 at 1:45

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lmfit.eval() producing wrong values of my model functions

Yes that was the problem! Thank you very much. It is all working now :) On Wed, Apr 24, 2024 at 1:45

Apr 23

Vanessa Carneiro Morita, Matt Newville3

Apr 5

Unexpected results for data with NaN values

Hi Matt, thanks again! I was in the process of writing/sending you the reply below when I had a click

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Unexpected results for data with NaN values

Hi Matt, thanks again! I was in the process of writing/sending you the reply below when I had a click

Apr 5

Levente Balogh, … Matt Newville5

Mar 21

Parameter fitting in parameter space with 'holes'

Hi Levi, That seems like a pretty tricky problem. You might be able to do it by remapping a "

unread,

Parameter fitting in parameter space with 'holes'

Hi Levi, That seems like a pretty tricky problem. You might be able to do it by remapping a "

Mar 21

Yehor Kosiachkin2

Mar 19

Global optimization algorithms are stuck in parameters boundaries

Sorry for the misleading information. It seems, that dual_annealing is not stucking on the boundaries

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Global optimization algorithms are stuck in parameters boundaries

Sorry for the misleading information. It seems, that dual_annealing is not stucking on the boundaries

Mar 19

sam mahdi, Matthew Newville4

Mar 6

Assistance in setting up constraints

I think your inequality constraint can give impossible values, say if CB > 10*(AB). That is, you

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Assistance in setting up constraints

I think your inequality constraint can give impossible values, say if CB > 10*(AB). That is, you

Mar 6

wenke ren, Matt Newville3

Mar 5

Results get worse by adding invariable parameters

Hi Matt, Thanks for your prompt reply. When I'm making a demo for this problem, I reallize that

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Results get worse by adding invariable parameters

Hi Matt, Thanks for your prompt reply. When I'm making a demo for this problem, I reallize that

Mar 5

adam najem, Matt Newville2

Feb 22

LMFIT and Numerical Simulation

Hi Adam, By default, each iteration for the `leastsq` method will call your objective or model

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LMFIT and Numerical Simulation

Hi Adam, By default, each iteration for the `leastsq` method will call your objective or model

Feb 22

p212121, … Antonio Bulgheroni8

Feb 17

Weights in lmfit

Thanks! Take it easy and thanks again for all your hard work! Cheers, toto --------------------------

unread,

Weights in lmfit

Thanks! Take it easy and thanks again for all your hard work! Cheers, toto --------------------------

Feb 17

Feb 15

Basinhopping only returns fit parameters of first iteration even though other minimas are lower.

Dear all, I dont know if there are minimal requirements for a code or so. Attached the code that I

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Basinhopping only returns fit parameters of first iteration even though other minimas are lower.

Dear all, I dont know if there are minimal requirements for a code or so. Attached the code that I

Feb 15

Jeremy DeJournett, Matt Newville3

Feb 11

Use of multiprocessing to speed up minimize()?

Thanks for illuminating that for me! I was thinking that you could parallelize the "brute force

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Use of multiprocessing to speed up minimize()?

Thanks for illuminating that for me! I was thinking that you could parallelize the "brute force

Feb 11

Anouk Volker, Matt Newville2

Feb 8

Uncertainty in fixed parameters/constants

Hi Anouk, As we almost always suggest, it would be helpful to have a script that shows more details

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Uncertainty in fixed parameters/constants

Hi Anouk, As we almost always suggest, it would be helpful to have a script that shows more details

Feb 8

Jenny Zhang, … Erik M5

Feb 8

param.stderr is extremely huge

If stderr is huge only for one parameter, I'd suspect that something is mistyped in the model

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param.stderr is extremely huge

If stderr is huge only for one parameter, I'd suspect that something is mistyped in the model

Feb 8

Antonio Bulgheroni (toto), Matt Newville3

Feb 3

Fitting performance

Dear Matt, thanks for your quick reply. Unfortunately I am running the code inside of a rather

unread,

Fitting performance

Dear Matt, thanks for your quick reply. Unfortunately I am running the code inside of a rather

Feb 3

Ahmed Abouhussein, Matt Newville2

Jan 10

Theoretical background on constraint handling

Hi Ahmed, On Wed, Jan 10, 2024 at 8:46 AM Ahmed Abouhussein <aabo...@asu.edu> wrote: > >

unread,

Theoretical background on constraint handling

Hi Ahmed, On Wed, Jan 10, 2024 at 8:46 AM Ahmed Abouhussein <aabo...@asu.edu> wrote: > >

Jan 10

Boris Deshev, Matt Newville3

12/30/23

Question about the parameters of the fit

Got it. Thanks! On Sat, Dec 30, 2023 at 4:52 PM Matt Newville <newv...@cars.uchicago.edu>

unread,

Question about the parameters of the fit

Got it. Thanks! On Sat, Dec 30, 2023 at 4:52 PM Matt Newville <newv...@cars.uchicago.edu>

12/30/23

Greg Pelletier, Matt Newville11

12/29/23

How do I get prediction intervals from eval_uncertainty() with an expression model?

Hi Matt, This is excellent news! Thank you very much for your hard work making these additions.

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How do I get prediction intervals from eval_uncertainty() with an expression model?

Hi Matt, This is excellent news! Thank you very much for your hard work making these additions.

12/29/23

Ham, … Greg Pelletier5

12/27/23

Calculating confidence interval AND prediction interval with lmfit

Here is a new githup repository where I put my new function to extend the capability of lmfit by

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Calculating confidence interval AND prediction interval with lmfit

Here is a new githup repository where I put my new function to extend the capability of lmfit by

12/27/23

12/26/23

Using the delta method to estimate confidence intervals and prediction intervals

Here is a new githup repository where I put my new function to extend the capability of lmfit by

unread,

Using the delta method to estimate confidence intervals and prediction intervals

Here is a new githup repository where I put my new function to extend the capability of lmfit by

12/26/23

12/25/23

New function using the delta method to calculate confidence intervals and prediction intervals

Dear all, Attached is a new function named delta_method to calculate the confidence interval of the

unread,

New function using the delta method to calculate confidence intervals and prediction intervals

Dear all, Attached is a new function named delta_method to calculate the confidence interval of the

12/25/23

Felix Boschetty, Matt Newville6

12/17/23

Iteratively calculating weights for least-squares fitting

Hi Matt, Thanks! you're very correct about both the square root, and that it is easier to

unread,

Iteratively calculating weights for least-squares fitting

Hi Matt, Thanks! you're very correct about both the square root, and that it is easier to

12/17/23

peja...@gmail.com, Matt Newville3

12/17/23

emcee with Model interface, version error with version 3.1.4

Hi Matt and thanks for your help (and the package, really really useful!) I have run it from a

unread,

emcee with Model interface, version error with version 3.1.4

Hi Matt and thanks for your help (and the package, really really useful!) I have run it from a

12/17/23

Cosme, Matt Newville3

12/13/23

Adding an offset with ModelResult.plot_fit ?

Hello Matt, Thanks a lot for your answer and sorry for not being clearer ! What I meant by offset is

unread,

Adding an offset with ModelResult.plot_fit ?

Hello Matt, Thanks a lot for your answer and sorry for not being clearer ! What I meant by offset is

12/13/23

12/9/23

Incorporation of Weights Results In Strange Fit

Hello All, I am a new user of lmfit, and I really appreciate what the module can do. However, I am

unread,

Incorporation of Weights Results In Strange Fit

Hello All, I am a new user of lmfit, and I really appreciate what the module can do. However, I am

12/9/23

a.m....@gmail.com, Matt Newville7

11/28/23

Optimise the diagonals of a set of matrices

I definitely ran the code and saw the plots :), in pycharm they appear in a separate browser-type

unread,

Optimise the diagonals of a set of matrices

I definitely ran the code and saw the plots :), in pycharm they appear in a separate browser-type

11/28/23

Sarah Kathryn Loughran, Matt Newville3

10/26/23

Help with optimizing minimization/objective function

While I plan on editing the getWind function in future, I am confident that is not the main problem.

unread,

Help with optimizing minimization/objective function

While I plan on editing the getWind function in future, I am confident that is not the main problem.

10/26/23

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